Standards

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Standards Information.

http://ec.europa.eu/growth/single-market/european-standards/harmonised-standards/electromagnetic-compatibility

For Directives click here

NKYS1612 Date: 161202 © J. M. Woodgate 2016

KNOW YOUR STANDARDS:

by J. M. Woodgate B.Sc.(Eng.) C.Eng.  MIET SMIEEE FAES  HonFInstSCE MIOA

Where do standards come from and who produces them?

Contrary to popular belief, standards are not produced by bureaucrats in Brussels or apparatchiks in Geneva, but by industry people like you and me (especially me!).  Of course, we are hired for our talents at electronics, not for our literary skills, so sometimes our writing falls short of the lucidity that is, nevertheless, essential in a standard, especially one that is associated with legislation or regulation, and that particularly includes standards for safety and for EMC.

What this amounts to is 'Don't suffer in silence.' When you find something in a standard that isn't comprehensible, or is comprehensible but cannot possibly be meant, please don't just fume and ignore it; tell someone  involved with that standard, or even me. It may take a while, but it will be fixed. If you are an IEEE member, the EMC-PSTC mailing list can be extremely helpful, especially for the requirements of countries outside Europe

Standards-making bodies

International

There are two groups of international standards bodies:

  • those established by treaty, or as organs of the United Nations, or by special international agreement, such as IEC (including CISPR), ISO and ITU. ITU is split into ITU-R, which produces non-mandatory requirements for broadcasting, and ITU-T, which produces requirements that it intends to be mandatory, for telecommunications;
  • those which are learned societies with international membership of individuals, such as IEEE and the Audio Engineering Society.

You might well conjecture that, on the basis of the perversity of human nature, that there is a degree of xenophobia between these two groups, but they do talk to each other.

CISPR (abbreviation of the French title) is part of IEC, but has a different Constitution, allowing government agencies, normally the spectrum management authorities, to be members, in addition to national standards bodies.

ETSI (European Telecommunication Standards Institute) appears from its title to be a Regional body, but it is a private membership organization, not a government agency, and has members from all over the world. Its importance has recently been greatly magnified by the spread of embedded radio transceivers in products that previously had no wireless communication and by the introduction of the EU Radio Equipment Directive (RED) with an extremely broad scope, replacing the far more limited RTTED (Radio and Telephone Terminal Equipment Directive) at extremely short notice.

Regional

Two bodies in this category are the European CENELEC (dealing with most electrical and electronics matters) and CEN, dealing with everything else. Their declared policy is to adopt IEC or ISO standards, respectively, wherever possible. 'Common Modifications' can be agreed by all participating countries, while 'Special National Conditions' are allowed where legal or major infrastructure requirements in particular countries make them necessary.

National

Every developed state, and most emergent states, has a national standards body, which is a member, or associate, of the international bodies. The UK Government is the ITU member, BSI is the ISO and CEN member, and also the member of IEC and CENELEC.

The British Standards INSTITUTION

Not 'Institute'! BSI is one of the oldest standards bodies and sometimes it shows. But Greek standards for metal parts used in masonry work were in place in Classical times (around 360 BCE)!

Most BSI committees parallel the work of international or regional committees. For example, BSI GEL/210/11 parallels IEC SC77A, SC77B and SC77C, and CISPR A, B, D, F, H and I. Membership of BSI committees is not very difficult to achieve, but you do tend to 'need to know someone', simply because it's not obvious how to apply. Not that there is often a queue of eager aspirants! However, unlike in almost all other countries, committee membership (as opposed to subscribing membership of BSI) is FREE. All you need to do is to devote your (employer's?) time and travel costs. If the committee sends you to a regional or international meeting, you may qualify for a government travel grant (AITS), which, in these days of budget air travel, may pay for a good percentage of the total cost.

Why standards matter for compliance

There are few countries in the world now that will allow products to be marketed without meeting requirements for safety and EMC (and maybe other things). While some require compliance with national standards, and others require testing in an indigenous laboratory, the demands for trade restrictions to be removed is strong enough to force the acceptance of IEC standards, or the substantial alignment of national standards with the IEC standards. There is also a growing number of mutual recognition agreements (MRA) between agencies, meaning that they accept test reports from laboratories in  each other's country.

Free trade and legal issues have also resulted in the abandonment, for most purposes, of mandatory compliance with standards and, to a large extent, mandatory third-party testing.  The result is that the manufacturer bears the whole, non-delegatable responsibility for a product being safe and  having sufficient electromagnetic compatibility, but can demonstrate that by any means that he wishes and expects to be acceptable to the market surveillance authorities.

The importance of 'design in' and the availability of standards at the 'solder face'

It seems incredible that there are still companies who either don't buy any standards or keep them locked up in the Technical Director's office. They hand over a 'finished' product from the design  engineers to specialist safety and EMC experts, who proceed to re-design it, at huge cost and with a long time delay, in order to comply with what they think are the mandatory regulations, because even they don't have free access to the standards and subsist on information from colleagues and the web, much of it not exactly wrong but misleading because of incompleteness.

It seems so obvious that the right way is to 'design-in' safety and EMC compliance from the beginning of the design process, with the experts involved at all necessary stages. In order for the designers and experts to talk the same language, and, especially, to prevent conflict, they must all have ready access to the relevant standards. If not, they soon begin to suspect that each expert has a personal agenda and is not just ensuring that the product complies. There isn't actually anything wrong with personal agendas, if they are in the open and recognized for what they are.  For example, how close to an EMC limit is 'too close for comfort'? The EMC expert may well say that from experience, this sort of product needs a 5 dB margin, whereas this sort needs only 3 dB.

How to obtain standards

ETSI standards are FREE and can be downloaded from http://www.etsi.org/ In many cases, the EMC standards come in pairs, one of general application and the other a version that satisfies the 'essential requirements' of whichever EU Directive it supports.

You can, of course, buy standards from BSI.  Be cautious about buying from 'official agents' – their mark-ups can be quite large.  If you buy from IEC or ISO, you may be able to buy only a bilingual publication, (English and French), which naturally costs more than for one language. Some IEC standards are published in Spanish.

Because of the 'Common Modifications' and 'Special National Conditions' mentioned above, the CENELEC or CEN adoption of an IEC or ISO standard is NOT identical to the original. How important the differences are depends crucially on what product is being considered. A detail that is of no significance at all for one product can require a substantial re-design of another. In addition, there are almost always differences in the 'Normative References' – standards mentioned in the text which give information on, for example, the methods of measurement that must be used. EMC ENs also have an Annex ZZ about how the standard matches up to the Directive.

ENs in English can be purchased from the national standards bodies of other European countries, often at attractive prices.  There is a comprehensive article, including a web-site linked list of standards-making bodies, at:

http://en.wikipedia.org/wiki/Standards_organization

The Estonian standards body (https://www.evs.ee/shop) offers many standards in English on a variety of financially attractive terms.

Participants in BSI's national and international standards work are given access, with restrictions, to the standards in their area of work. BSI Project Managers can give committee members access to related standards if they are needed for reference in connection with work on another standard.

What do you do next?

Having obtained your standard, you put it in a safe place, intending to read it later, don't you? Preferably not! The plot is thin and the characterization poor, so it's only a bit better than the average TV play, but you need to read it carefully, and not once but several times, with your product in front of you, so that you can see how each clause of the standard relates to your particular concerns. This applies also to the Normative References – standards having provisions that are effectively provisions of the standard you are reading. There may be many of these, and you don't have to buy them all. You look at each reference where it appears in the body of the standard, not in the Normative references clause, and consider whether your product is affected or not.

If there is anything you don't understand, or think it makes no sense, do ask advice, from colleagues or wider on the Internet

 

More (and more!) standards-making bodies

There is another way of classifying standards-making bodies, which does not fit too well with the natural progression International - Regional - National, so is best treated separately. This classification distinguishes between those bodies which may roughly be described as 'public institutions' (into which fall ITU, IEC, ISO, CENELEC, CEN and most National Committees) and those that are substantially privately-constituted bodies, which have a fee-paying membership.  We dealt with the former type last time, but mentioned only  ETSI and learned societies in the context of membership bodies. There are three main types of such bodies.

Membership bodies

Other membership bodies that are also standards-makers include IEEE and the Audio Engineering Society, as mentioned last time. There are numerous such bodies, not only learned societies but also trade association and other industry groups, active at the national level, and in some cases their deliverables are adopted as official National standards - this option is available in USA through ANSI, for example. One of the most prominent of these bodies is Ecma International (formerly the European Computer Manufacturers Association, ECMA). Ecma mostly works in co-operation with ISO/IEC JTC1 - the international forum for the IT standards movement. It produces standards and technical reports, which are respected by most of the major IT manufacturers but not all, which is liable to create compatibility problems. Ecma publications are available FREE to all.

A third category of standards body is set up to develop, promote and control a particular technology, and usually includes intellectual property rights (IPR) licensing as part of its activity.  There may be only one 'standard'  - setting the requirements for interchangeability between products using the technology. One well-known example is the DVD Forum, and others are the USB Implementers Forum and the MIDI Manufacturers Association. There is a huge number of such bodies, some more prominent and successful than others.

Supra-national bodies

These bodies rarely come to the notice of standards users, but are very influential directly on the International bodies, often through shared experts. Many were established a long time ago, when the language of  international affairs was French. Those that are often concerned with EMC matters include:

CEPT Conférence Européenne des administrations des postes et des télécommunications

Formed in 1959, this body pre-dates the breaking of the monopolies on telecommunication held by national postal authorities in Europe. It still co-ordinates the postal and infra-structure telecommunications services in a 'Greater Europe' that includes the Russian Federation and Turkey. As such, it is a major player in ITU-T, and was responsible for the creation of ETSI, so you know who to blame.

CIGRÉ Conseil International des Grands Réseaux Électriques (which is not quite so easily guessed in English: International Council on Large Electrical Systems. It really does use accented upper-case letters in the French).

It is a sort of hybrid between a standards-making body and a learned society for the science and engineering of large-scale electric power distribution. Apart from its central organization, it has nearly 60 National Committees. Its 'standards', called 'Technical Brochures', are used directly by members, but also influence IEC committees such as CISPR/B and IEC SC77A.

CIE Commission Internationale de l'éclairage (International Commission on Lighting)

Similar to CIGRÉ, CIE studies the science underlying colour and its perception, but also produces guidance on all applications of lighting, including image technology, so interfaces with a number of IEC and ISO committees. Lighting represents a major use of electric power, and the lighting load has quite rapidly changed from largely resistive incandescent lamps to more efficient, but non-linear compact fluorescent and LED lamps, so CIE has been involved in the applicable EMC standards committees CISPR/F and IEC SC77A.

 

Producing new standards

Many people think we have far too many standards already, and that is probably true, but finding out which ones we don't need is difficult. Meanwhile, we should only make a new standard if it is justified, and most standard-makers have a procedure for seeking justification; some work better than others.  In IEC, at least five (normally) National committees have to vote to accept a New Work proposal AND nominate experts to do the work. In several recent cases, there was ample support for the proposal but too few nominations for experts! It's easy to support a project if you expect someone else to do all the work!

These days, technology moves so fast that a standard could easily be out-of-date before it passes final voting.  The minimum practical period for producing a new standard is three years, allowing for one comment stage and two voting stages, as in IEC and ISO. But this works only if the subject is non-controversial and technically rather simple. In other cases, more than one comment stage and more than two voting stages may be required.

Making standards intelligible, unambiguous and accessible

IEC and ISO have quite strict editorial rules, compiled from many years experience, but these can only really impose a uniform structure and, to some extent, control the use of verb forms so as to distinguish between compulsion (shall), recommendation (should), permission (may) and possibility (can). However, the English language being what it is (almost all international standards are drafted in English), it's awfully easy to slip in a 'have to' or 'is to' instead of 'shall'.  'Must' and 'must not' are reserved for compulsion not under the control of the standards-writers, such as the need not to violate the laws of physics. This may all seem very pedantic, but maybe not when you realise that the German 'muss' means 'must', but 'muss nicht ' means 'need not'. And that isn't the same meaning as the 'need not' in the sentence about physics!

Above all, it is necessary to keep the language as simple as possible. To simplify the wording of this article, I'm now going to assume that you have become a new standards writer. 'Simple'  means simple sentence construction, not necessarily avoiding long words, as long as they are technical; 'permeability' is OK, but not 'quintessence'! It's awfully easy to use stylistic 'tricks', such as inverted word order or 'tech-speak' - 'speaker' instead of 'loudspeaker' (they are quite different words in other languages), which are blindingly obvious to a native English speaker but very confusing to someone, let's say Mr Sum,  who learned three other languages before English. And when you need to write the same thing several times, such as in a test procedure, use the same words every time. You are not writing a homework essay for Mr Beelzebub, the English teacher, to whom repetition is anathema, you are striving not to confuse Mr Sum, who sees different words and wonders what the difference in procedure actually is.

Keeping standards up-to-date

Even if a standard is still up-to-date when it is published, it will not stay that way for long. (Incidentally, the use of 'that way' is an example of what is likely to confuse a standards reader. Write '…it will not stay up-to-date for long.').

IEC and ISO have a formal 'maintenance procedure', which was written up very confusingly in the past but is now explained more lucidly in the latest ISO/IEC Directives. These are the rules of the whole ISO/IEC standards 'game', and to do well you need to know the rules.  Luckily, they are free downloads from http://www.iec.ch/members_experts/refdocs/. All three parts, Part 1, Part 2 and the IEC Supplement, are very recently revised, with quite a number of changes, so even if you already have them you probably need to download the new ones.

When a standard is published, it comes with a 'stability date', of 3 to 12 years (in a special case 15 years), when the next version is expected to be published, not when work is to start on the new version. So, if the stability date is only 3 years ahead, maintenance work has to start immediately the standard is published (or even, informally, before then).  To start the formal process, a 'Document for Comment' (DC) is (should be) sent to National Committees, recommending re-confirmation, withdrawal or revision. If revision is recommended, an outline of what revision is proposed may be attached. National committees are asked to comment on the recommendation and, in the case of revision, to review their representation on the responsible committee or to nominate members to a new Maintenance Team. When the responses are collated, a Review Report (RR) is circulated to National Committees, explaining what is planned to be done. Unfortunately, the rules allow an RR to be circulated without a DC, which presents National Committees with a surprise (this is the first notice that the standard was considered for amendment, revision or withdrawal) and a fait accompli – the standard's fate has already been decided, without consultation. This is not likely to impress a concerned National Committee.

Retiring standards

Some standards deal with technology that is no longer in use – TV picture tubes for example. The associated standards may be withdrawn, and in the past, In ISO and IEC, it was very difficult to obtain a copy of a withdrawn standard even if it was really needed. However, withdrawn IEC standards are now available (but not free).

In other cases, a technology may no longer be in wide use but IS still in use for special applications or for historical and archival purposes.

Note - Some people are very fearful about the future loss of access to stored digital information of high importance, and indeed it has happened - the BBC Domesday project used an adapted form of the Philips Laserdisc technology, but access was very nearly lost through negligence - read the whole sorry story at: http://en.wikipedia.org/wiki/BBC_Domesday_Project

For the relevant standards of this type of technology, IEC and AES have adopted the term 'stabilized standards', which are preserved as current but are not expected to change for at least 15 years. An example is the standard (IEC (60)098) dealing with vinyl disc playback, which is undergoing a huge come-back at present.

 

Recap

Over the last two issues, we looked at the standards-making bodies and their characteristics, how one can obtain standards economically, what to do with them when you have them (most important!) and how one can participate in standards work (masochism is not essential, but it helps).

Types of standards publication

There is a problem with terms, because the word 'standard' is used, even by standards-making bodies, to mean various sorts of publication, only one of which is a 'standard' as normally understood, i.e. a prescriptive document, using 'shall' as the verb for its provisions.  Not so many years ago, the then edition of BS 0 (BS Zero – 'A standard for standards') listed ten types of publication, and used 'specification' to mean the prescriptive type, which nevertheless are called 'standards'. Furthermore, the terms differ between standards bodies.

IEC and ISO publications

These publications are numbered as IEC [prefix] NNNNN-nn-nnn, ISO [prefix] NNNNN-nn-nnn or ISO/IEC NNNNN-nn-nnn. The '-nn-nnn' refer to Parts and Sections of multipart standards and are absent from single standards. At one time, especially in IEC, the first N was 6, but now other numbers appear in that position for standards on different major topics.

·    Standards (no prefix) – prescriptive documents;

·    Technical reports (TR) –descriptive documents; under current rules may not even give recommendations, using 'should';

·    Technical specifications (TS) – 'wannabe' standards - NOT to be regarded as standards but they can use prescriptive language. May be turned into standards after experience has been gained of their use or they may continue to exist as a 'halfway house';

·    Guides (numbered in their own series); in spite of the name, many of them are prescriptive; they concern the content of standards, their relations with other standards and how they are to be developed. They are generated by high-level committees and are addressed to Technical Committees, not normally to standards users.

·    Publicly-available specifications (PAS) – documents originated elsewhere that are candidates for adoption as standards after experience has been gained of their use.

There are two suffixes, indicating different variations of the same edition:

·        CSV – Consolidated version of a publication with its amendments and any corrigenda;

·        RLV – Red line version, including both the 'clean' text of the standard and a marked-up version showing where it differs from the previous edition.

CISPR

Although CISPR is part of IEC, it has its own Constitution and its own numbering system. Publications are numbered in the form CISPR [prefix] NN-nn-nn. They are published by CISPR sub-committees, not CISPR itself. There seems to be no rule that prevents CISPR sub-committees producing all the same varieties of publication, except Guides, as the rest of IEC, but at present it has only TRs and PASs.  Generic EMC standards produced by CISPR/H are numbered in the IEC 61000-6 series.

CEN and CENELEC

These publications are numbered as EN (or TR) NNNNN-nn-nnn, but in CEN, the number of Ns may be fewer. ENs are 'European Standards', not 'Euronorms' which are quite different publications, from a different source.

·    Standards (EN) – prescriptive documents;

·    Technical reports (TR) – usually descriptive documents, may give recommendations, using 'should', but are definitely not prescriptive;

·    Technical specifications (TS) – 'wannabe' standards - NOT to be regarded as standards but they use prescriptive language. May be turned into standards after experience has been gained of their use or they may continue to exist as a 'halfway house';

·    Harmonized documents (numbered in their own series HD NNNNN-n-nnn) – prescriptive documents adopted when due to different legal or other circumstances in EC member states, an EN could not be implemented verbatim in all states. The number of Ns is variable. Examples are standards for cables and those for electrical installations, such as BS 7671, which is the British implementation of HD 60364;

·    Guides (numbered in their own series);these are not the same as IEC or ISO Guides and are not always prescriptive.

In CENELEC, the first two Ns indicate the origin and nature of the standard:

·    EN 50NNN-nn-nnn – a standard prepared and published by CENELEC;

·    EN 55NNN-nn-nnn – a standard adopted from CISPR, therefore an EMC standard. The last two Ns and any ns are taken from the CISPR number;

·    EN 6NNNN-nn-nnn – a standard adopted from IEC; the 6 may be replaced by another digit except 5;

EN 55NNN and EN 6NNNN standards are very similar to the original CISPR or IEC standards but are never identical; the difference may be trivial or very significant, and that varies from case to case. A difference may be trivial to others but profoundly affect your product.

These standards adopted from IEC or CISPR may include 'Common Modifications', which apply across Europe, and Special National Conditions, which apply only in the states which request them. A few standards still include 'A deviations', which are necessitated by legal provisions or infrastructure conditions that cannot be readily or reasonably changed. In an Annex ZA, the Normative References are replaced by references to ENs and HDs if they exist. Annex ZB usually contains the Special National Conditions, if there are any. EMC and safety standards include an Annex ZZ that details how the standard matches the provisions of the Directive. There may be other important  differences (important to your product, if to no other) between the EN and the standard from which it was derived.

Harmonized

There is another terminology problem with this word. Originally, all ENs and HDs were 'harmonized' – meaning 'implemented in all EU states'. But the Commission hi-jacked the term (probably inadvertently and no-one bothered to challenge it) to mean only those standards listed in the Official Journal, conformity with which conveys prima facie evidence of compliance with a Directive.

Implementation

IEC and ISO standards are recommended to the organizations' members – the national standards bodies – for adoption nationally. They are not 'recommendations' in the sense of being only advisory. Problems have been caused by some National Committees implementing standards that are referred to in legislation, such as safety and EMC standards, immediately on publication by IEC or ISO. A case occurred some years ago where products were legal when put in a ship but illegal when taken out of it in a far country! IEC and ISO do not specify 'transition periods' but call the attention of National Committees in the Forewords of such standards that transition periods may be required at national level so that industry has time to manufacture products conforming to the new standard.

In CEN and CENELEC the procedure is more detailed. National Committees must implement published ENs, even if they voted against them. There is a sequence of critical dates, some of which are listed in the actual publication:

date of ratification (dor)

date when the Technical Board notes the approval of an EN (and HD for CENELEC), from which time the standard may be said to be approved

date of availability (dav)

date when the definitive text in the official language versions of an approved CEN/CENELEC publication is distributed by the Central Secretariat

date of announcement (doa)

latest date by which the existence of an EN (and HD for CENELEC), a TS or a CWA has to be announced at national level

date of publication (dop)

latest date by which an EN has to be implemented at national level by publication of an identical national standard or by endorsement

date of withdrawal (dow)

latest date by which national standards conflicting with an EN (and HD for CENELEC) have to be withdrawn

All these are determined by CEN or CENELEC, but there is also another one, of very high importance, that is determined by the Commission. This is the fabulous beast 'docopocoss' – the (BIG breath!) date of cessation of presumption of conformity of the superseded standard. This is listed against each standard notified in the Official Journal as providing prima facie evidence of conformity with a Directive. A newly-listed standard can be used immediately, but industry has a transition period, usually of three years, before the former standard reaches the docopocoss and may no longer be referred to in Declarations of Conformity.

The docopocoss is normally the same as the dow, but the Commission reserves the right to set a different date, and occasionally exercises that right.

Know Your Standards

by J. M. Woodgate B.Sc.(Eng.) C.Eng.  MIET SMIEEE FAES  HonFInstSCE MIOA

Saga

There are several  different types of 'standards publication', so a table to summarize would be useful. It is based on the way IEC identifies types, because that is the most 'structured' way. Rather than the cumbersome 'standards publication'. it is convenient to use 'publication' to mean any of these except Guide, and use 'Standard' when we mean only a fully normative publication.

Type of publication

Abbreviation

Description

Standard

none

'Normative' (i.e. prescriptive) document; uses 'shall' for provisions, 'should' for recommendations and 'may' for permissions (and preferably not for probability)

Technical Report

TR

Review, survey or generally descriptive document. Not allowed to use 'shall', 'may' or 'should'.

Technical Specification

TS

A possible future standard or a normative document which has strong support but no consensus for publication as a standard; uses 'shall', 'may' and 'should'

Publicly-available Specification

PAS

Normative document obtained from another body that may become an IEC standard after experience of its use has been gained; uses 'shall', 'may' and 'should'

Guide

none

One of a separate series of documents, addressed to standards committees rather than standards users. Some Guides are normative, or have parts that are normative.

Test Report Form

TRF

Guess? These official forms are not mandatory, but impress clients. They can be quite costly

 

There is another classification system that helps to understand the relationships between standards that deal with the same product type.

Class

Description

Product standard

Deals with the characteristics of the product as they affect its application. Can include methods of measurement or performance requirements, or both (then it must be a Standard)

Methods of measurement Standard

Deals only (or almost only) with methods of measurement

Performance Standard

Deals with performance from the user's point of view

'Regulatory' performance Standard

EMC Standard, Safety Standard or Human Exposure to EM energy Standard.

 

 

 

Even that is not the end of the story, because 'regulatory' standards have a classification of their own, but implemented differently in safety and EMC standards!

Type

Description of Safety Standard

Description of EMC Standard

Generic

Gives requirements that are applicable to products that do not have an applicable product family or product standard and set a benchmark for the requirements specified in those standards

Usually Part 1 of a multi-part standard; includes methods of measurement

Gives requirements that are applicable to products that do not have an applicable product family or product standard and sets a benchmark for the corresponding requirements specified in those standards

A Standard in the IEC 61000-6 series

Basic

Rare; an example is IEC 60990 on measurement of touch current. Often about methods of measurement.

Gives methods of measurement that are applicable to most product families; maybe suggests numerical requirements based on those methods

Standards in the IEC 61000-4 series and the CISPR 16 series

Product Family

Deals with a range of products using closely similar technology; usually a Part other than Part 1, or a section of Part 2, of a multi-part standard. May include additional methods of measurement

Deals with a range of products using broadly similar technology (maybe very broad, e.g. IEC 61000-3-2 and -3 cover almost all mains-powered products)

Standards in the IEC 61000-3 series and CISPR NN-n standards, except the CISPR 16 series, also some standards produced by product committees.

Product

Deals with a closely-defined product; usually a section of Part 2 of a multi-part standard

Some standards produced by product committees. Some cover immunity only.

Support

A TR or TS that gives guidance and recommendations where a Standard does not exist, or gives supporting explanations of a standard (e.g. IEC/EN TR 62368-2)

A TR or TS that gives guidance and recommendations where a Standard does not exist.

 

Generic safety Standards

There are too many of these to list, but notable ones include IEC 62368-1, IEC 60065 (consumer electronics), IEC 60204-1 (machinery), IEC 60335-1 (household appliances), IEC 60601-1 (medical), IEC 60950-1 (ITE and office machines) and IEC 61010-1 (measuring instruments, industrial process control and laboratory equipment).

The EN versions of all of these have varying degrees of difference from the IEC version. Since even a small difference may affect YOUR product profoundly, it is most unwise to consult the IEC version when the EN applies, or vice versa.

NOTE IEC/EN 60065 and IEC/EN 60950-1 will be superseded by IEC 62368-1. At present, this is planned for year 2020. But it is practically essential to  take IEC/EN 62368-1 into account now, because it is very different from its predecessors.

 

 

Generic EMC standards

Reference

Property

EMC environment

IEC 61000-6-1

Immunity

Residential, commercial and light industry

IEC 61000-6-2

Immunity

(Heavy) Industrial

IEC 61000-6-3

Emission

Residential, commercial and light industry

IEC 61000-6-4

Emission

(Heavy) Industrial

IEC TS 61000-6-5

Immunity

Power station and sub-station

IEC 61000-6-7

Immunity

Safety-related industrial systems

 

Basic safety Standards

There are few of these with wide application, except IEC 60990, already mentioned above.

Note  The terms 'basic safety Standard' and 'basic safety publication' are not of the same meaning.

Basic EMC Standards

Reference

Description

IEC 61000-4-1

Overview of the IEC 61000-4 series

IEC 61000-4-2

Immunity to electrostatic discharge (ESD)

IEC 61000-4-3

Immunity to radiated radio-frequency electromagnetic fields

IEC 61000-4-4

Immunity to fast transients or bursts

IEC 61000-4-5

Immunity to surges

IEC 61000-4-6

Immunity to conducted disturbances induced by radio-frequency fields

IEC 61000-4-7

Measurement of harmonics and interharmonics of the power supply

IEC 61000-4-8

Immunity to power frequency magnetic field

IEC 61000-4-9

Immunity to pulse magnetic field

IEC 61000-4-10

Immunity to damped oscillatory magnetic field

IEC 61000-4-11

Immunity to voltage dips, short interruptions and voltage variations

IEC 61000-4-12

Immunity to ring-wave

IEC 61000-4-13

Immunity of the AC power port to harmonics, interharmonics and low-frequency mains signalling

IEC 61000-4-14

Immunity to voltage fluctuations

IEC 61000-4-15

Flickermeter functional and design specifications

IEC 61000-4-16

Immunity to conducted common-mode disturbances, 0 Hz to 150 kHz

IEC 61000-4-17

Immunity to ripple on DC input power port

IEC 61000-4-18

Immunity to damped oscillatory wave

IEC 61000-4-19

Immunity to conducted differential-mode disturbances and signals 2 kHz to 150 kHz at AC power ports

IEC 61000-4-20

Emission and immunity testing in transverse electromagnetic (TEM) waveguides

IEC 61000-4-21

Reverberation chamber test methods

IEC 61000-4-22

Radiated emissions and immunity measurements in fully-anechoic rooms (FARs)

IEC 61000-4-23

Test methods for protective devices for high-altitude electromagnetic pulse (HEMP) and other radiated disturbances

IEC 61000-4-24

Test methods for protective devices for HEMP conducted disturbance

IEC 61000-4-25

Immunity test methods for HEMP for equipment and systems

IEC 61000-4-26

Not issued

IEC 61000-4-27

Immunity to unbalance [of 3-phase power supplies] for equipment with input current not exceeding 16 A per phase

IEC 61000-4-28

Immunity to variation of power frequency for equipment with input current not exceeding 16 A per phase

IEC 61000-4-29

Immunity of DC power ports to voltage dips, short interruptions and voltage variations

IEC 61000-4-30

Measurement of power quality

IEC 61000-4-31

Immunity to broadband conducted disturbances at AC power ports

IEC TR 61000-4-32

High altitude electromagnetic pulse (HEMP) simulator compendium

IEC 61000-4-33

Measurement methods for high-power transient parameters

IEC 61000-4-34

Immunity of equipment with input current more than 16 A per phase to voltage dips, short interruptions and voltage variations

IEC 61000-4-35

High-power electromagnetic (HPEM) simulator compendium

IEC 61000-4-36

Intentional electromagnetic interference (IEMI) immunity test methods for equipment and systems

IEC TR 61000-4-37

Calibration and verification protocol for harmonic emission compliance test systems

IEC 61000-4-38

Test, verification and calibration protocol for voltage fluctuation and flicker compliance test systems

IEC 61000-4-39

Immunity to radiated fields in close proximity (not yet published, in March 2017)

IEC 61000-4-40

Digital methods for measuring power quantities of modulated or distorted signals (not yet published, in March 2017)

 

The above descriptions are not necessarily the titles of the standards, some of which murder the English language. The French titles are, of course, much more grammatical.  The 'not issued' standard exists as a title in an IEC TC77 internal master list but may never be developed and published. Further offerings, beyond Section 40, are to be expected.

Installation and mitigation guidelines

There is a growing band of these. This 61000-5 series was envisaged as non-normative, but that appears to be not true for some Sections. Some of them contain wording which is now prohibited in IEC standards.

Reference

Description

IEC TR 61000-5-1

General considerations (Basic EMC publication)

IEC TR 61000-5-2

Earthing and cabling

IEC TR 61000-5-3

HEMP protection concepts

IEC TS 61000-5-4

Specifications for protective devices against HEMP radiated disturbance (Basic EMC publication)

IEC 61000-5-5

Specifications for protective devices against HEMP conducted disturbance (Basic EMC publication)

IEC 61000-5-6

Mitigation of external electromagnetic (EM) influences

IEC 61000-5-7

Degrees of protection of EM enclosures (EM code)

IEC 61000-5-8

HEMP protection methods for the distributed infrastructure

IEC 61000-5-9

System-level susceptibility assessments for HEMP and HPEM

IEC TS 61000-5-10

Guide to the application of HEMP and IEMI specifications (not yet published, in March 2017)

    

Time to be specific

Having looked in previous issues of KYS at  standards bodies and the ways that standards can be divided into types and classes, it's time to look at specific standards, and for EMC, the two biggies are CISPR 16 and IEC 61000-4, both divided into many Parts and Sections.

CISPR 16

This once was a standard of a modest 50 pages or so, but expanded to well over 100 and now is a multi-part standard with numerous sub-divisions. It is developed by CISPR/A -  Radio-interference measurements and statistical methods, except for CISPR TR 16-2-5 and TR 16-4-4, which are developed by CISPR/H.

There follows is a list of the current publications at the time of writing. The list is continually updated, and is freely available on the public part of the IEC web site. There is little point in citing one of the very long direct URLs, but you can drill down through the structure:

www.iec.ch -> Dashboard Finder -> Technical Committee -> CISPR/CIS/A -> Projects/Publications -> Publications

There you will find all the amendments and corrigenda, as well as details of bilingual (English/French) and monolingual (English, French or Spanish) editions, together with Stability Dates - the date before which no change to the standard is expected.

This search works for all IEC and CISPR technical committees and sub-committees, of course, not just for CISPR/A.

 Components of CISPR 16

A publication code such as CISPR 16-1-1 indicates:

CISPR - Originating body

16 - Publication number

1 - Part number

1- Section number

Note: Sub-divisions of the text of a standard are clauses, not sections or even chapters (which may be  a mistranslation from German).  Some standards with a long history still have 'chapters' as major divisions of the text.

A package of all of CISPR 16 can be purchased from IEC, but you have to be very rich:

CISPR 16:2015 OC

Edition 1.0 (2015-04-23) – ON-LINE COLLECTION – Specification for radio disturbance and immunity measuring apparatus and methods - ALL PARTS

Most people not in test houses need only selected publications. This list does not include 'RLV' red line versions, which show changes from the previous edition, and if there is a 'CSV'  consolidated version with amendments and/or corrigenda, the standard and its amendments and corrigenda are not listed separately.

CISPR 16-1-1:2015

 Edition 4.0 (2015-09-22) Specification for radio disturbance and immunity measuring apparatus and methods - Part 1-1: Radio disturbance and immunity measuring apparatus - Measuring apparatus

CISPR 16-1-2:2014

 Edition 2.0 (2014-03-21) Specification for radio disturbance and immunity measuring apparatus and methods - Part 1-2: Radio disturbance and immunity measuring apparatus - Ancillary equipment - Conducted disturbances

CISPR 16-1-3:2004+AMD1:2016 CSV

 Edition 2.1 CSV (2016-03-31) Specification for radio disturbance and immunity measuring apparatus and methods - Part 1-3: Radio disturbance and immunity measuring apparatus - Ancillary equipment - Disturbance power

CISPR 16-1-4:2010+AMD1:2012+AMD 2:2017 CSV

 Edition 3.2 (2017-01-19) Specification for radio disturbance and immunity measuring apparatus and methods - Part 1-4: Radio disturbance and immunity measuring apparatus - Antennas and test sites for radiated disturbance measurements

 CISPR 16-1-5:2014+AMD1 2016 CSV

 Edition 2.0 (2014-12-17) Specification for radio disturbance and immunity measuring apparatus and methods - Part 1-5: Radio disturbance and immunity measuring apparatus - Antenna calibration test sites for 30 MHz to 1 000 MHz

 CISPR 16-2-1:2014

 Edition 3.0 (2014-02-26) Specification for radio disturbance and immunity measuring apparatus and methods - Part 2-1: Methods of measurement of disturbances and immunity - Conducted disturbance measurements

CISPR 16-2-2010

Edition 2.0 (2010-07-28) Specification for radio disturbance and immunity measuring apparatus and methods - Part 2-2: Methods of measurement of disturbances and immunity - Measurement of disturbance power

CISPR 16-2-3:2016

 Edition 4.0 (2016-09-15) Specification for radio disturbance and immunity measuring apparatus and methods - Part 2-3: Methods of measurement of disturbances and immunity - Radiated disturbance measurements

 CISPR 16-2-4:2003

 Edition 1.0 (2003-11-20) Specification for radio disturbance and immunity measuring apparatus and methods - Part 2-4: Methods of measurement of disturbances and immunity - Immunity measurements

CISPR TR 16-2-5:2008 (developed by CISPR/H)

Edition 1.0 (2008-07-09) Specification for radio disturbance and immunity measuring apparatus and methods - Part 2-5: In situ measurements for disturbing emissions produced by physically large equipment

 CISPR/TR 16-3:2010+AMD1:2012+AMD2:2015 CSV

 Edition 3.2 (2015-09-15) Specification for radio disturbance and immunity measuring apparatus and methods - Part 3: CISPR technical reports

CISPR/TR 16-4-1

Edition 2.0 (2009-02-23) Specification for radio disturbance and immunity measuring apparatus and methods - Part 4-1: Uncertainties, statistics and limit modelling - Uncertainties in standardized EMC tests

CISPR 16-4-2:2011+AMD 1:2014 CSV

 Edition 2.1 (2014-02-14) Specification for radio disturbance and immunity measuring apparatus and methods - Part 4-2: Uncertainties, statistics and limit modelling - Measurement instrumentation uncertainty

CISPR/TR 16-4-3:2004+AMD1:2006 CSV

 Edition 2.1 (2007-01-18) Specification for radio disturbance and immunity measuring apparatus and methods - Part 4-3: Uncertainties, statistics and limit modelling - Statistical considerations in the determination of EMC compliance of mass-produced products

CISPR/TR 16-4-4:2007 (developed by CISPR/H)

Edition 2.0 (2007-07-16) Specification for radio disturbance and immunity measuring apparatus and methods - Part 4-4: Uncertainties, statistics and limit modelling - Statistics of complaints and a model for the calculation of limits for the protection of radio services

CISPR/TR 16-4-5:2006+AMD1:2014 CSV

 Edition 1.1 (2014-07-21) Specification for radio disturbance and immunity measuring apparatus and methods - Part 4-5: Uncertainties, statistics and limit modelling - Conditions for the use of alternative test methods

These publications have been written (and some repeatedly partly re-written) over the years by numerous people, so there are inconsistencies in language and style. CISPR intends to deal with this, but don't hold your breath!

The intention, also, is to collect into CISPR 16-1 and -2 all except the most specialized methods of measurement from other CISPR standards. Those that are worth retaining from CISPR 13, 20, 22 and 24 have already been included.

One point to beware of is the risky mixing in some of these standards of decibels and impedances in ohms. I pointed the problem out through BSI some years ago and it seemed to be accepted that a change was necessary, but later the comment was rejected. Even so, I believe it is valid. Consider :

V = IR

Convert to dB: the multiplier must clearly be 20 for all:

20lgV = 20lgI - 20lgR

Now consider:

W = V2/R

Convert to dB:

10lgW = 10lg(V2) - 10lgR

The multiplier must clearly be 10.

So, to convert 150 ohms to dB (which is needed as a correction factor in some calculations), do you multiply 2.18 by 10 or 20? Rather than mixing decibels with ohms, the correction can just be expressed as a number, explaining that it is derived from the 150 ohm impedance.

CISPR TR 16-3

This Technical Report is not widely known, but it is well worth study. It explains a lot about EMC and CISPR standards that isn't explained elsewhere. It isn't adopted by CENELEC, but it is published by BSI. Unfortunately, it is quite costly.

IEC 61000-4

This also needs a whole article to do it justice, so that will have to wait for the next issue.

Deep breath!

We are now due to start looking at the monster multi-section standard IEC 61000-4.  IEC 61000-4 is a collection of Basic EMC standards (according to some, Parts 7 and 15 aren't Basic). There is a Section of IEC 61000-4 for every EMC susceptibility phenomenon (emission phenomena are covered by CISPR 16) and every method of measuring immunity that the EMC experts have found necessary or consider might be necessary.

What this means is that they address two groups, and this is important to understand, because an IEC 61000-4 series standard does not apply to a product unless the product or product-family standard has it as a Normative reference (not just an informative reference).

The first group is product (and product-family) EMC Committees. IEC 61000-4 says to them, 'If your product needs an immunity test method and one or more test levels for this phenomenon, make this Section a Normative reference in your standard, and select from its recommended test levels that or those which suit your product's intended environment'.

The second group addressed is those who want to carry out the tests. IEC 61000-4 says to them 'That’s the way to do it.' In some cases, the instructions are rather too terse or opaque for comfort. They are almost always too costly for comfort!

IEC TR 61000-4-1

This is an overview of the whole 61000-4 series that was deemed a standard but is now a Technical Report. It may be helpful for understanding but it is not a Basic standard ; no product can conform to it because it sets no requirements for a product. It is mainly a guidance document, but it does include information on the relationship between immunity requirements and the electromagnetic environment. It also includes tables showing which tests relate to various ports of the equipment under test. It also sets requirements for test reports, which is curious because so do most of the other Parts.

IEC 61000-4-2

This section deals with immunity to electrostatic discharge (ESD), which is a very difficult subject. Unlike, for example, emissions from a high-speed switching device, ESD is usually a random chance event, caused by a charged body (which may be somebody) coming close to, or touching, a point on the surface (or, in the case of inter alia servicing, the interior) of a product. In fact, 'close' may not be necessary; there is a possibly apocryphal story of Band 1 (50 MHz) TV reception in Brighton suffering interference that was traced to the students at Roedean girls' public school discarding nylon underwear en masse at bedtime. It's certainly true that the TV signal, from Alexandra Palace in those days, was very weak in Brighton.

Once a discharge event has occurred, it's impossible to know where the energy went unless it causes detectable damage, and in many cases, it's a mystery how the discharge current gets back to the high-voltage source. No-one really knew how the test equipment and the devices made to verify its operation actually behaved until oscilloscopes with bandwidths of several gigahertz became available. At that time, some people wanted to improve the test equipment but this was resisted on the grounds that it actually offered very little advantage over the existing equipment and might lead to new results inconsistent with previous ones.

The EMC consultant and lecturer Douglas C Smith has published a large amount of very interesting experimental data on ESD and other EMC subjects, which can be traced through http://emcesd.com/

IEC 61000-4-3

This Section covers immunity to radio-frequency fields, to which almost all equipment is continuously exposed. This subject has probably been studied longer than any other in EMC, so the methods and requirements are well established. Measurement in the open air is no longer legally possible, so an anechoic chamber is required. These, of course, are large and costly, so other methods have been developed which are the subjects of later Sections.

IEC 61000-4-4

The subject here is immunity to 'electrical fast transients/bursts'. Such transients occur on the public mains supply due to switching and other events. Sixty years ago, equipment was generally much more resistant to high-voltage transients, so there was no need for any testing, but there is now. Direct-on-line selenium rectifiers, replacing vacuum rectifiers, had stacks of diodes in series, so were also resistant to transients, and it came as a bit of a surprise how high the peak inverse voltage rating of single-junction silicon rectifiers had to be in order to achieve adequate reliability.

IEC 61000-4-5

This Section is about a 'surge immunity test'. Surges can occur on power supply cables and on signal cables, especially if they leave a building. This is another case where equipment has become much less inherently resistant over the years.

IEC 61000-4-6

Much equipment is too small, and too close to the ground, to act as an efficient receiving antenna for potentially disturbing radio-frequency signals, but cables can be fairly efficient antennas. In that case, the radio-frequency energy is presented to the equipment as conducted currents. The test methods require the use of 'coupling and decoupling devices' to control where those currents flow. Unfortunately, while these devices are fairly simple, many different types are required, not only to suit different cables but also to accommodate the huge number of different connectors that are used these days.

In the past, the standard did not cover 9 kHz to 150 kHz, but that frequency range is now covered in the 2008 edition.

IEC 61000-4-7

This is described as a 'general guide' and it started out that way, but it is now a specification for a measuring instrument for power system harmonic currents and voltages. The title may be changed in a future edition. Measuring harmonics of 50 Hz or 60 Hz sounds an easy task, but in fact there are many complications. Some transient high levels of harmonics are not considered unacceptable so can either be averaged out or, in other cases, specifically accepted. Also, the instruments are now digital, so special precautions are necessary to overcome certain 'features' of the Digital Fourier Transform, used to perform the frequency analysis.

The standard includes provisions for 'grouping' interharmonics (signals at non-harmonic frequencies) with adjacent harmonics by using a measurement bandwidth of 50 Hz or 60 Hz, but this has been found to be too stringent for some equipment which is in use without causing significant interference. So those provisions are at present suspended, by allowing the use of a method of measurement, with a 5 Hz bandwidth, that does not include grouping. Work is actively in progress to try to eliminate that, but it has so far proved too difficult. Maybe one day....

IEC 61000-4-8

Power frequency magnetic fields can cause many problems; obviously audio equipment in various forms may be particularly affected, but so can video displays and any equipment that handles very small voltages or currents may be disturbed by induced currents in conducting loops. The recommended test levels of continuous field strength range from 1 A/m to 100 A/m, but anything above 5 A/m is now considered inadvisable for human exposure in this frequency range. For fault conditions, the highest value is 1000 A/m, and even though that is supposed to last for no more that 3 seconds, i.e. until the fault is cleared by a protective device, the bioelectric effects (nerve stimulation by induced currents) are considered to act in time scales of tens of milliseconds.

The magnetic fields are supposed to be generated by large (1m square and 1 m by 2.6 m) single-turn coils, which require hundreds and even thousands of amps to produce the required field strengths, but the standard does allow other coil configurations to be used, provided that field strength is verified. It is a bit surprising that the test procedure requires a ground plane, but not necessarily a very large one. It isn't clear what the ground plane is supposed to do.

IEC 61000-4-9

The subject of this Section is a 'pulsed magnetic field immunity test', which is considered applicable only to products installed in electrical power plants.

IEC 61000-4-10

This Section is about another 'power plant' phenomenon, 'damped oscillatory magnetic field immunity test'.  It is interesting that neither this Section or the previous one are called up in IEC TS 61000-6-5, Generic TS for immunity for power-and sub-station environments. However, that publication is under review and may become a standard that does reference IEC 61000-4-9 and -10.

I think ten Sections is enough for now, so look forward to further excitement next time. The last Section at present is IEC 61000-4-39, but number 26 hasn't been used. It was supposed to be about 'calibration of probes', but little progress was made in six years, so the project was cancelled. It could be revived. An attempt to produce a Section 40 on advanced power-system measurements had to be at least postponed, due to a lack of consens

KNOW YOUR STANDARDS

by J. M. Woodgate B.Sc.(Eng.) C.Eng.  MIET SMIEEE FAES Hon FInstSCE MIOA

NKYS17-05       Date: 17-05-06  © J. M. Woodgate 2017

Deep breath!

We are now due to start looking at the monster multi-section standard IEC 61000-4.  IEC 61000-4 is a collection of Basic EMC standards (according to some, Parts 7 and 15 aren't Basic). There is a Section of IEC 61000-4 for every EMC susceptibility phenomenon (emission phenomena are covered by CISPR 16) and every method of measuring immunity that the EMC experts have found necessary or consider might be necessary.

What this means is that they address two groups, and this is important to understand, because an IEC 61000-4 series standard does not apply to a product unless the product or product-family standard has it as a Normative reference (not just an informative reference).

The first group is product (and product-family) EMC Committees. IEC 61000-4 says to them, 'If your product needs an immunity test method and one or more test levels for this phenomenon, make this Section a Normative reference in your standard, and select from its recommended test levels that or those which suit your product's intended environment'.

The second group addressed is those who want to carry out the tests. IEC 61000-4 says to them 'That’s the way to do it.' In some cases, the instructions are rather too terse or opaque for comfort. They are almost always too costly for comfort!

IEC TR 61000-4-1

This is an overview of the whole 61000-4 series that was deemed a standard but is now a Technical Report. It may be helpful for understanding but it is not a Basic standard ; no product can conform to it because it sets no requirements for a product. It is mainly a guidance document, but it does include information on the relationship between immunity requirements and the electromagnetic environment. It also includes tables showing which tests relate to various ports of the equipment under test. It also sets requirements for test reports, which is curious because so do most of the other Parts.

IEC 61000-4-2

This section deals with immunity to electrostatic discharge (ESD), which is a very difficult subject. Unlike, for example, emissions from a high-speed switching device, ESD is usually a random chance event, caused by a charged body (which may be somebody) coming close to, or touching, a point on the surface (or, in the case of inter alia servicing, the interior) of a product. In fact, 'close' may not be necessary; there is a possibly apocryphal story of Band 1 (50 MHz) TV reception in Brighton suffering interference that was traced to the students at Roedean girls' public school discarding nylon underwear en masse at bedtime. It's certainly true that the TV signal, from Alexandra Palace in those days, was very weak in Brighton.

Once a discharge event has occurred, it's impossible to know where the energy went unless it causes detectable damage, and in many cases, it's a mystery how the discharge current gets back to the high-voltage source. No-one really knew how the test equipment and the devices made to verify its operation actually behaved until oscilloscopes with bandwidths of several gigahertz became available. At that time, some people wanted to improve the test equipment but this was resisted on the grounds that it actually offered very little advantage over the existing equipment and might lead to new results inconsistent with previous ones.

The EMC consultant and lecturer Douglas C Smith has published a large amount of very interesting experimental data on ESD and other EMC subjects, which can be traced through http://emcesd.com/

IEC 61000-4-3

This Section covers immunity to radio-frequency fields, to which almost all equipment is continuously exposed. This subject has probably been studied longer than any other in EMC, so the methods and requirements are well established. Measurement in the open air is no longer legally possible, so an anechoic chamber is required. These, of course, are large and costly, so other methods have been developed which are the subjects of later Sections.

IEC 61000-4-4

The subject here is immunity to 'electrical fast transients/bursts'. Such transients occur on the public mains supply due to switching and other events. Sixty years ago, equipment was generally much more resistant to high-voltage transients, so there was no need for any testing, but there is now. Direct-on-line selenium rectifiers, replacing vacuum rectifiers, had stacks of diodes in series, so were also resistant to transients, and it came as a bit of a surprise how high the peak inverse voltage rating of single-junction silicon rectifiers had to be in order to achieve adequate reliability.

IEC 61000-4-5

This Section is about a 'surge immunity test'. Surges can occur on power supply cables and on signal cables, especially if they leave a building. This is another case where equipment has become much less inherently resistant over the years.

IEC 61000-4-6

Much equipment is too small, and too close to the ground, to act as an efficient receiving antenna for potentially disturbing radio-frequency signals, but cables can be fairly efficient antennas. In that case, the radio-frequency energy is presented to the equipment as conducted currents. The test methods require the use of 'coupling and decoupling devices' to control where those currents flow. Unfortunately, while these devices are fairly simple, many different types are required, not only to suit different cables but also to accommodate the huge number of different connectors that are used these days.

In the past, the standard did not cover 9 kHz to 150 kHz, but that frequency range is now covered in the 2008 edition.

IEC 61000-4-7

This is described as a 'general guide' and it started out that way, but it is now a specification for a measuring instrument for power system harmonic currents and voltages. The title may be changed in a future edition. Measuring harmonics of 50 Hz or 60 Hz sounds an easy task, but in fact there are many complications. Some transient high levels of harmonics are not considered unacceptable so can either be averaged out or, in other cases, specifically accepted. Also, the instruments are now digital, so special precautions are necessary to overcome certain 'features' of the Digital Fourier Transform, used to perform the frequency analysis.

The standard includes provisions for 'grouping' interharmonics (signals at non-harmonic frequencies) with adjacent harmonics by using a measurement bandwidth of 50 Hz or 60 Hz, but this has been found to be too stringent for some equipment which is in use without causing significant interference. So those provisions are at present suspended, by allowing the use of a method of measurement, with a 5 Hz bandwidth, that does not include grouping. Work is actively in progress to try to eliminate that, but it has so far proved too difficult. Maybe one day....

IEC 61000-4-8

Power frequency magnetic fields can cause many problems; obviously audio equipment in various forms may be particularly affected, but so can video displays and any equipment that handles very small voltages or currents may be disturbed by induced currents in conducting loops. The recommended test levels of continuous field strength range from 1 A/m to 100 A/m, but anything above 5 A/m is now considered inadvisable for human exposure in this frequency range. For fault conditions, the highest value is 1000 A/m, and even though that is supposed to last for no more that 3 seconds, i.e. until the fault is cleared by a protective device, the bioelectric effects (nerve stimulation by induced currents) are considered to act in time scales of tens of milliseconds.

The magnetic fields are supposed to be generated by large (1m square and 1 m by 2.6 m) single-turn coils, which require hundreds and even thousands of amps to produce the required field strengths, but the standard does allow other coil configurations to be used, provided that field strength is verified. It is a bit surprising that the test procedure requires a ground plane, but not necessarily a very large one. It isn't clear what the ground plane is supposed to do.

IEC 61000-4-9

The subject of this Section is a 'pulsed magnetic field immunity test', which is considered applicable only to products installed in electrical power plants.

IEC 61000-4-10

This Section is about another 'power plant' phenomenon, 'damped oscillatory magnetic field immunity test'.  It is interesting that neither this Section or the previous one are called up in IEC TS 61000-6-5, Generic TS for immunity for power-and sub-station environments. However, that publication is under review and may become a standard that does reference IEC 61000-4-9 and -10.

I think ten Sections is enough for now, so look forward to further excitement next time. The last Section at present is IEC 61000-4-39, but number 26 hasn't been used. It was supposed to be about 'calibration of probes', but little progress was made in six years, so the project was cancelled. It could be revived. An attempt to produce a Section 40 on advanced power-system measurements had to be at least postponed, due to a lack of consensus

The story continues...

Are we ready for a second helping of premium immunity standard? Last time, we looked at IEC 61000-4-1 to -10, so now we have to enter the second decade.

IEC 61000-4-11

This is a standard about tests for immunity to power-frequency phenomena, specifically voltage dips, short interruptions and voltage variations. These low-frequency standards are produced by IEC SC77A, while the high-frequency standards (above 9 kHz, with some exceptions) are produced by SC77B. Not all product standards call up IEC 61000-3-11, because the products concerned, such as heaters, are not seriously affected by these disturbances.

Amendment 1 to this standard has just been published. It adds an informative Annex D which explains certain controversial features of the specification of the test generator. Some National Committee61000-4s did not support this amendment.

IEC 61000-4-12

The ring wave immunity test is not well known; indeed, what is a 'ring wave'? The standard says it's a damped oscillatory transient, so it should really be called a 'ringing wave', because a tuned circuit is said to 'ring' like a bell, as it produces such a decaying transient when prodded with a suitable pulse. Indeed, the basic test signal generator uses this technique. The tuned circuit resonates at 100 kHz, and is prodded by the voltage on a charged capacitor. This voltage may be as low as 250 V or as high as 4 kV, depending on the conditions set in the product standard. The test generator Is a powerful beast ; it can deliver up to 333 A.

A new edition is expected to be published this year.

IEC 61000-4-13

This is about immunity to harmonics and interharmonics, including mains signalling, at a.c. power ports for products rated at 16 A per phase or less. The 'mains signalling' concerned is 'ripple control' which is not used in Britain, but is used in many countries. An on-off modulated  signal at a frequency in the range 105 Hz to 1995 Hz (125 Hz to 2395 Hz in 60 Hz systems), unrelated to the mains frequency, is used to control remote equipment in the distribution system. Most, but not all, of the recommended voltage test levels are well below 10 % of the supply voltage.

The standard has been amended twice, in 2009 and 2015, so any future amendment will cause the creation of a new edition.

IEC 61000-4-14

IEC 61000-4-11 is about immunity to, amongst other things, voltage dips and variations. IEC 61000-3-14 is about immunity to voltage fluctuations. So, what's the difference? We have to look at the definitions in the standards.

In Section 11 (i.e. IEC 61000-4-11), we have:

voltage dip

a sudden reduction of the voltage at a particular point of an electricity supply system below a specified dip threshold followed by its recovery after a brief interval

Curiously, 'voltage variation' is not formally defined and we have to look at the test conditions to find out what it is:

Voltage variations (optional)

This test considers a defined transition between rated voltage UT and the changed voltage.

NOTE The voltage change takes place over a short period, and may occur due to change of load.

The preferred duration of the voltage changes and the time for which the reduced voltages are to be maintained are given in Table 3. The rate of change should be constant; however, the voltage may be stepped. The steps should be positioned at zero crossings, and should be no larger than 10 % of UT. Steps under 1 % of UT are considered as constant rates of change of voltage.

The description 'optional' is curious; it should really be for product standards to specify which tests should be done.

 

Table 3 – Timing of short-term supply voltage variations

 

Voltage test level

Time for decreasing voltage (td)

Time at reduced voltage(ts)

Time for increasing voltage (ti) (50 Hz/60 Hz)

70 %

Abrupt

1 cycle

25/30b cycles

Xa

Xa

Xa

Xa

a To be defined by product committee.

b "25/30 cycles" means "25 cycles for 50 Hz test" and "30 cycles for 60 Hz test".

 

 

In Section 14, we have:

voltage fluctuations

series of voltage changes or a cyclic variation of the voltage envelope [IEV 161-08-05]

So, we see that variations are assumed non-repetitive, whereas fluctuations are repetitive. Well, maybe.

This standard was amended in 2001 and 2009, so we may see a third edition

IEC 61000-4-15

Like IEC 61000-4-7, this is not a Basic standard but the specification of a measuring instrument – in this case, the Flickermeter. The instrument is designed to output numerical values consistent with the subjective effects of rapid voltage variations on the light output of a 60 W coiled-coil incandescent lamp, which is, of course, now nominally an extinct species. However, it was agreed not to revise the standard to change the reference device to a compact fluorescent lamp, because these products will quite soon be superseded by affordable LED lamps. At the same time, lamp manufacturers are being encouraged to make lamps which are no more sensitive to flicker than the 60 W lamp.

Flicker can be very disturbing to people of an anxious disposition – they fear that the power will go off or even that a fire or explosion might occur. Unfortunately, on rare occasions, they might be right.

An Interpretation Sheet (ISH) is due to be published later this year.

IEC 61000-4-16

This is one of the few Basic standards about low-frequency phenomena; in this case it's immunity to conducted, common-mode disturbances in the frequency range 0 Hz to 150 kHz. So it's also one of the few standards that crosses the 'great divide' at 9 kHz, between 'low' and 'high' frequencies. The Scope clause admits that it is of limited applicability - to equipment including cables more than 20 m long, mostly in industrial plants. The disturbances are launched on the power system cables, in common-mode, i.e. line and neutral voltage fluctuate together with the same polarity. However, they may couple to other cables, especially in the case of the higher-frequency disturbances produced by power electronic equipment using switching techniques.

The tests are divided into three categories:

·        mains frequencies (16.67 Hz, 50 Hz and 60 Hz) short-term;

·        mains frequencies long term;

·        other frequencies (15 Hz to 150 kHz).

No tests are specified below 15 Hz, except at d.c. (0 Hz). A d.c test signal generator is specified, with an output voltage adjustable between 1 V and 30 V and an output source impedance of 50 ohms.

A very significant consideration is that the means for injecting the disturbance to balanced communication ports may seriously degrade the common-mode rejection by applying unequal source impedances to the two inputs. This is acknowledged, but the relevant Note has an unfortunate omission of the word 'not':

NOTE It may [NOT] be possible to produce T networks suitable for use with common mode rejection ratios greater than 80 dB, in which case the product standard should define an alternative coupling method.

IEC 61000-4-17

This Section defines test methods for immunity to ripple at the d.c. input power port of electrical or electronic equipment, and applies to low-voltage d.c. power ports of equipment supplied by external rectifier systems, or batteries which are being charged. The disturbance level is specified as the ratio of the peak-to-peak ripple voltage to the d.c. voltage, and test levels are from 2 % to 15 %. The waveform is the 'sine cap and linear decay' typically produced by a rectifier.

IEC 61000-4-18

This deals with another rare phenomenon – the damped oscillatory wave, to be carefully distinguished, of course, from the 'ring wave', which is a damped oscillatory wave! So, what's the difference? IEC 61000-4-12 specifies only a damped 100 kHz signal, where as IEC 6100-4-18 specifies signals at 100 kHz and 1 MHz, described as 'slow' signals, and 3 MHz, 10 MHz and 30 MHz, described as 'fast' signals. The whole standard is oriented to these disturbances being produced by switching and other operations in power stations, or caused by a high-level electromagnetic pulse (HEMP) (which we hope is of natural origin!). However, text in the Scope (which it appears should have been deleted in favour of other, similar text), refers to 'electrical and electronic equipment intended for residential, commercial and industrial applications'. The skeleton test signal generator circuit is more complex than that specified in IEC 61000-4-12.

A revision is at an early stage of development.

IEC 61000-4-19

This has not yet been published, being still at the CD stage ((but is available as BSI Draft for Public Comment 12/30258875). It is about immunity to conducted, differential mode disturbances in the frequency range 2 kHz to 150 kHz. (IEC 61000-4-16 is about immunity to conducted, common-mode disturbances.) Test signals are either 60 second 'tone bursts' of sine-wave signals, the frequency incrementing by 2% for each burst, or tone bursts, in the same frequency range, of increasing duration from 1.6 ms to 330 ms (for 50 Hz mains).  The switching instants are not synchronized to the mains frequency.

IEC 61000-4-20

This Section is about emission and immunity testing in transverse electromagnetic (TEM) waveguides. Unlike most standards, it includes a lot of mathematics. It may be better to follow the instructions of the TEM test device rather than the more generalized treatment in the standard.

A revision is under development.

There are at present eighteen more Sections (and one failure) of IEC 61000-4 to look at, before we go on to other delights later this year

In view of the fact that we stopped our review of the Sections of IEC 61000-4 at Part 20 last time, we should start with Section 21, if it exists, and indeed it does. At present, there is no work scheduled on any of these standards, so we have a welcome period of stability. But it may not last.

IEC 61000-4-21

Section 21, extensively revised in 2011, is about tests in reverberation chambers, but humorous vocalizations are not even mentioned. It concerns tests of immunity and intentional or unintentional emissions for electric and/or electronic equipment and tests of screening effectiveness. Conducted emissions are excluded. It is quite long (114 pages) and very detailed. As for IEC 61000-4-20, it may be best to follow the instructions of the particular chamber in use.

As for all Basic EMC standards, it does not prescribe tests or limits for specific products or product families. These are determined by the relevant product committees, in consultation with CISPR and IEC TC77. However, a Note indicates that the responsible committee considers that simulations are not adequate for quantitative determinations.

IEC 61000-4-22

This section, first published in 2010, is about measurements of radiated emissions and immunity to them in fully-anechoic rooms (FARs). It is much shorter than Section 21, and covers the frequency range 30 MHz to 18 GHz. Nevertheless, it goes into much detail about the measurements and how to ensure that they are as accurate as possible. The method is generally more suited to physically small products, although large FARs do exist. The results are expressed as electric field strength, since the measurements are not in the far field at lower frequencies.

There are signs of inadequate editing; for example the above-mentioned Note in the Scope is more or less repeated as main text, and clause 4.2 more or less repeats the latter half of clause 4.1. However, there don't appear to be cases of inadequate clarity.

IEC 61000-4-23

This and the next two Sections are about HEMP (High-altitude ElectroMagnetic Pulse), defined as such a pulse produced by a nuclear explosion outside the Earth's atmosphere, so with luck, it appears that it can be omitted from detailed study by most people. No CENELEC versions (EN) of Sections 23 and 24 exist, because the few people who need the standard can obtain the IEC version. However, it does include data useful in other circumstances, such as the shielding effectiveness of an 0.5 mm thick aluminium enclosure against electric and magnetic fields from 100 Hz to 10 MHz. There is also a four-page annex on the characteristics of coaxial cables.

This Section, updated in 2016,  is 'Test methods for protective devices for HEMP and other radiated disturbances' Clearly, this might involve smoke and loud noises (there actually is a test described as 'the smoke test'), and indeed full-scale testing using a high-power Marx generator and a large guided-wave structure (tens of metres) is described. Another set-up uses a very large bicone antenna suspended from a helicopter and driven by a 1.5 MV Marx generator. However, less spectacular methods of measurement are also described. One surprising thing is that a diagram said to be of a Rogowski coil does not show the characteristic feature – that the lead-out from one end of the toroidal coil is fed through the centre of the winding to the other end of the coil, so that the terminations are close together.

IEC 61000-4-24

This is 'Test methods for protective devices for HEMP conducted disturbance', and is a less exciting document than is included in Section 23. A second edition was published in 2015. In principle, the device under test is enclosed in a screening box and zapped with a high-voltage pulse, to see how much energy it lets through.

 

 

IEC 61000-4-25

There is a new 2012 edition of this Section, 'HEMP immunity test methods for equipment and systems'. It is actually the 2002 edition with Amendment 1 embodied. It is concerned with laboratory tests, as opposed to the large-scale tests described in IEC 61000-4-23. Rather too many trivial or obvious definitions are included, as is a wordy description of 'radiated' and 'conducted', part of which is then repeated! The tests are described as being carried out in simulators, in contrast to statements in other standards that simulation is not reliable. For conducted disturbances, three types of disturbance, characterized by early, intermediate and late time of arrival at the EUT, are considered. Early time disturbances are represented by the IEC 61000-4-18 damped sinusoid for lower energies, the 5/50 ns pulse of IEC 61000-4-4- for intermediate energies and pulses defined in Section 25 itself for the highest energies. For intermediate time, the 10/700 µs pulse of IEC 61000-4-5 is used, while for late time, Section 25 defines a 60 s trapezoidal pulse. Generators for the waveforms described in the Section are also specified. Future updates are unlikely to be adopted as ENs.

IEC 61000-4-26

This was to be 'Calibration of probes and associated instruments for measuring electromagnetic fields', but that subject is really for CISPR/A to deal with, so the project was cancelled.

IEC 61000-4-27

The title of this Section is: Testing and measurement techniques - Unbalance, immunity test for equipment with input current not exceeding 16 A per phase. In fact it applies only to true 3-phase load equipment for 50 Hz or 60 Hz supplies, not 3-phase and neutral equipment that actually presents independent single-phase loads to the network.

Unbalance (different phase voltages and/or interphase angles) can be caused by large single-phase loads, arc furnaces and fault conditions. Induction motors present an abnormally-low impedance to unbalanced supplies, similar to that under starting conditions. Overheating, to the point of severe and dangerous damage, may occur. Other loads may be disturbed so as to produce abnormal conducted harmonic current emissions. Control equipment that does not have sensors on all three phases may operate incorrectly. Abnormal acoustic noise is also a possibility.

Immunity is determined by applying deliberately unbalanced supplies, and evaluating the response of the EUT according to the usual Performance Criteria, including Criterion D – unrecoverable loss of function.

IEC 61000-4-28

This Section is: Variation of power frequency, immunity test for equipment with input current not exceeding 16 A per phase. It applies only to 50 Hz and 60 Hz equipment. The Scope says that the standard should not be applied to products that do not show significant lack of immunity to the small variations of supply frequency that are characteristic of most public supplies, which means most products.

As usual for immunity testing, the results are assessed in terms of the Performance Criteria.

IEC 61000-4-29

This one is called: Voltage dips, short interruptions and voltage variations on d.c. input power port immunity tests

It's written in terms of quite high-power DC distribution systems – the test generator is specified for up to 36 V output at up to 25 A. But this subject really needs to be considered for quite low-power products; in most cases there is enough stored energy in capacitors across the supply to tide over any short interruptions, but not always. For example, a product was quite immune unless an incandescent lamp alarm indicator was on; if an interruption occurred then, the microprocessor reset and the alarm indicator went out. Not good!

IEC 61000-4-30

The subject of this Section, updated in 2015,  is Testing and measurement techniques - Power quality measurement methods, and it is, actually, a 'hot topic', although this isn't widely publicised. The point is that governments have determined that electric power is a commodity that must have consumer-protection quality standard applied to it, such as EN 50160 (which, in my opinion isn't  standard at all, but something between a promise and a prediction). So the supply authorities are committed to 24/365.24 monitoring of voltage value, stability and unbalance, frequency, waveform purity and mains signalling voltages.

Three levels of measurement are specified - Class A (precision), Class S (good enough for statistics!) and Class B ('grandfather' class for existing instrumentation). For classes A and S, the basic measurement time interval is 20 ms. Measurements are then aggregated over intervals of 3 s, 10 min and 2 h. Measurements must be continuous, with no gaps. Details are given of how to assess voltage dips, swells and interruptions, unbalance and harmonics. There is a large amount of detailed information about other matters, even down to specifications for test leads and practical guidance on their use. It seems doubtful that the people who need this information are able to obtain it directly from the standard, but must be able to get the information form training courses based on it.

That's all for this time: there are a few more Sections (some still in their eggshells) to be considered before we move to another fascinating field.

If there is a standard or standards that YOU would like me to dissect, please use the response email address. Please note that I cannot quote long sections of text, nor pass them on by email, and I cannot answer a question like 'What is the difference between the 2005 version and the 2009 version?', because it's too complicated to relate every little change, and an apparently trivial change may be very significant for YOUR product, if for no-one else's.

 

We are coming to the end of the survey of the huge IEC 61000-4 series of Basic EMC standards (those defining the methods of measurement of (mostly) immunity characteristics and, in some cases, specifying the test equipment). However, because the survey began a while back, we need to look for updates to the earlier Sections as well.

As for all of the IEC 61000-4 series standards, these standards and Technical Reports apply only if normatively referenced in product or product-family EMC standards.

IEC 61000-4-31

Immunity to conducted disturbances, induced by intentional and/or unintentional broadband signals)

This standard was published in July 2016, and is important in the context of signalling on the supply mains, although that subject seems to be fading from interest.

IEC TR 61000-4-32

High-altitude electromagnetic pulse (HEMP) simulator compendium

This has not been adopted by CENELEC or BSI. It gives information on HEMP simulators and their applicability for immunity test requirements. It includes datasheets describing 42 EMP simulators that could be available for use by the international community.

IEC 61000-4-33

Measurement methods for high-power transient parameters

This standard provides a basic description of the methods for measuring responses arising from high-power transient electromagnetic parameters, such as: the electric (E) and/or magnetic (H) fields; the current  and voltage induced by a transient field or within a system under test; and the charge Q induced on a cable or other conductor. These are generally complicated time-dependent waveforms, which can be described approximately by several "observables". It does not provide information on specific level requirements for testing.

IEC 61000-4-34

Voltage dips, short interruptions and voltage variations immunity tests for equipment with rated input current of more than 16 A per phase

The standard applies for single and 3-phase connections at 50 Hz or 60 Hz (but it's not adopted in the Americas yet). An important Normative Reference is that to IEC 61000-2-8, a not very well-known Technical Report on the statistics of occurrence of these disturbances. Apart from the statistical data, it contains a lot of information about electricity supply networks that may be difficult to obtain elsewhere.

IEC TR 61000-4-35

HPEM simulator compendium

This comprehensive Report (88 pages) gives details of High-Power Electromagnetic (HPEM) simulators and their use for immunity testing. It includes numerous definitions of terms and a survey of the increasing use of high-power electronic systems and its implications for the prevention of interference with other, safety-critical electronic systems.

IEC 61000-4-36

IEMI immunity test methods for equipment and systems. This was published in 2014.

It provides methods for the assessment of equipment and systems to IEMI (Intentional ElectroMagnetic Interference) environments. These environments are defined in IEC 61000-2-13 (see below). It explains the differences between natural and intentional high power electromagnetic environments and plugs a gap in the IEC series of publications defining HEMP and HPEM environments and HEMP test methods. It provide test methods for those HPEM environments that can be generated by criminals or terrorists for malicious purposes, namely IEMI.

IEC TR 61000-4-37

Calibration and verification protocol for harmonic emission compliance test systems

This was published in 2016. It is of interest to test houses who need to be sure that their testing arrangements are strictly in accordance with the applicable standards.

IEC TR 61000-4-38

Calibration and verification protocol for flicker compliance test systems

This was published in 2015. Its application is the same as for Section 37.

IEC 61000-4-39

Radiated fields in close proximity – Immunity test

This standard was published in March 2017. It is needed to cope with things like mobile phones being very close to other equipment.

IEC TR 61000-4-40

Digital methods for the measurement of power quantities of modulated or distorted signals

Work on this Section has stopped and it may be withdrawn from the Programme of Work. It was not possible to obtain consensus on the usefulness of RMS values calculated over periods other than one or more whole cycles.

Cross-reference

IEC 61000-2-13:2005 defines a set of typical radiated and conducted HPEM environment waveforms that may be encountered in civil facilities. For the purposes of this standard, high-power conditions are achieved when the peak electric field exceeds 100 V/m. This limits the application of this standard to EM radiated and conducted environments that are substantially higher than those considered for "normal" EMC applications, which are covered by other standards. As such, it may be of significance in the context of functional safety.

UPDATES

This information is accessible only to a very limited extent from the public part of the IEC web site for TC77/SC77B 'Projects/Publications' 'Work programme'. The actual documents are available only to committee members, including members of the BSI Committee. Some members may not be very familiar with parts of the BSI committee web site, which has more dark recesses than the Cheddar Gorge.

The way, or at least a way, is to go to the BSI committee front page and select 'Projects' from the 'Library Containers' menu. Scroll down to the IEC 61000 series folder and click on it, then scroll down to the IEC 61000-4 series folder and click on it. The 'Modified' column on the far right indicates the last change date, and can be used to select (by clicking on) those folders that may include new documents, but some do not. Even so, new documents associated with each Section can be found this way.

IEC 61000-4-3

The first CD for Edition 4 was circulated to National Committees in August 2017. It gives a non-exhaustive list of the changes from Edition 3:

·        Testing using multi-tone signals;

·        New information on EUT and cable layout.

It will attract numerous editorial comments, because ISO/IEC Directives Part 2 has not been applied.

IEC 61000-4-5

A DC was circulated in June 2017 on proposed clarification of Edition 3:

·        Using the 'Edition 2' surge generator

·        Clarification of the improvements in Edition 3;

·        Clarification that 'Section 5 surges' should not be applied to antenna ports.

IEC 61000-4-6

A DC (Document for Comment) was circulated to National Committees in August 2017, concerning a fourth edition (or an amendment, if the agreed changes are not too extensive). A list of 16 detailed improvements is proposed.

IEC 61000-4-11

A Call for Comments on the preparation of a Third Edition was circulated and resulted in six pages of proposals. However, there is no  explicit statement of the next step.

IEC 61000-4-15

An Interpretation Sheet giving a clarification of the wording of sub-clause 6.8 on rectangular voltage modulation was approved without comment.

EN 61000-4-23

CENELEC finally agreed to withdraw the 2000 edition, so that the latest edition can be published by European NCs.

IEC 61000-4-30

A DC for the preparation of Edition 4 was circulated in June 2017. It lists five fairly substantial improvement proposals, including a complementary TR on power quality issues for LVDC (Low Voltage Direct Current) supplies.

NKYS1709                      Date: 17-09-24                © J. M. Woodgate 2017     (12-11)

Know Your Standards

by J. M. Woodgate B.Sc.(Eng.) C.Eng.  MIET SMIEEE FAES Hon FInstSCE MIOA

Previews of IEC and CISPR standards

If you go to http://webstore.iec.ch/, and search in Webstore for a standard series (e.g. 61000), a Part (61000-1) or Section (61000-1-1) you can 'preview' a document (well, almost all of them) by clicking on the icon in the left column of the search result page. This allows you to read the Foreword, Scope and Normative References clauses FREE of charge. In some cases, what you can read is different, because some publications don't follow the normal clause plan. Previews are not available for some old (but still current) standards.

Painting the 4th Part

We completed the review of the Sections of Part 4 of IEC 61000 last time, but standards change continuously, so we will need to re-visit in due course.  Meanwhile, we have five other Parts to enjoy. The listings now include the issue date at the time of writing the list. The Webstore makes it easy to check for the latest edition, including amendments and corrigenda.

IEC 61000-1 series

The Sections of this Part are Technical Reports and Technical Specifications ('pre-standards').

IEC TR 61000-1-1:1992

Electromagnetic compatibility (EMC) - Part 1: General - Section 1: Application and interpretation of fundamental definitions and terms

This dates is no longer very useful. It should really be withdrawn.

IEC 61000-1-2:2016

Electromagnetic compatibility (EMC) - Part 1-2: General - Methodology for the achievement of functional safety of electrical and electronic systems including equipment with regard to electromagnetic phenomena

This is now a standard, not a Technical Specification (TS). It is very complex, as is the whole subject of functional safety. But it can't be ignored.

IEC TR 61000-1-3:2002

Electromagnetic compatibility (EMC) - Part 1-3: General - The effects of high-altitude EMP (ElectroMagnetic Pulse) (HEMP) on civil equipment and systems

This is informative. Let's hope we never find out whether the information is dependable!

IEC TR 61000-1-4:2005

Electromagnetic compatibility (EMC) - Part 1-4: General - Historical rationale for the limitation of power-frequency conducted harmonic current emissions from equipment, in the frequency range up to 2 kHz

This is an excellent document (because I wrote most of it). (;-) Its only real justification is that the requirements remain complex and controversial, so as each new generation of EMC experts challenges them, they can be directed to the rationale. They can't, of course, be made to believe it.

IEC TR 61000-1-5:2004

Electromagnetic compatibility (EMC) - Part 1-5: General - High power electromagnetic (HPEM) effects on civil systems

This is not only about the effects of things that go bang on a large scale, but also about magnetic storms and other unusual phenomena.

 

 

 

IEC TR 61000-1-6:2012

Electromagnetic compatibility (EMC) - Part 1-6: General - Guide to the assessment of measurement uncertainty

This is another very complex subject that can't be ignored. But do you need to calculate an uncertainty budget when you measure the voltage of a dry cell to see if it is of any more use? There really is pressure to apply uncertainty principles to measurements that really don't need them. Long years ago, before most of the world heard of uncertainty, a sentence was put in an IEC standard that advises the user to consider what the results are to be used for, and use this to determine the required precision and accuracy, and now we would add 'uncertainty'.

IEC 61000-1-7:2016

Electromagnetic compatibility (EMC) - Part 1-7: General – Power factor in single-phase circuits under non-sinusoidal conditions

IEC 61000-2 series

These are mostly informative documents, and are well worth studying, because they answer some, but not all, of the Frequently Frustrating Questions.

IEC TR 61000-2-1:1990

Electromagnetic compatibility (EMC) - Part 2: Environment - Section 1: Description of the environment - Electromagnetic environment for low-frequency conducted disturbances and signalling in public power supply systems

For electronics engineers, not so familiar with the intricacies of power systems, this is particularly useful. 'Signalling' means 'ripple control' - the injection of audio-frequency tone bursts into a system to control system equipment and loads, such as street lighting. It's not used in Britain, but is widely used on the Continent and in Australia and New Zealand. It can obviously affect zero-crossing detectors.

IEC 61000-2-2+AMD1:2017

Electromagnetic compatibility (EMC) - Part 2-2: Environment - Compatibility levels for low-frequency conducted disturbances and signalling in public low-voltage power supply systems

This is regarded as a standard, but nothing is expected to conform to it directly. Its purpose is to form the basis for determining limits for the conducted emissions of products. It has been updated in 2017 by adding:

– compatibility levels for signals from mains communicating systems up to 150 kHz;

– compatibility levels for non-intentional emissions between 2 kHz and 30 kHz.

A second amendment is expected soon, containing:

– compatibility levels for non-intentional emissions between 30 kHz and 150 kHz.

IEC TR 61000-2-3:1992

Electromagnetic compatibility (EMC) - Part 2: Environment - Section 3: Description of the environment - Radiated and non-network-frequency-related conducted phenomena

This is a large document, practically a textbook on basic EMC principles, but is costly.

IEC TR 61000-2-4:2002

Electromagnetic compatibility (EMC) - Part 2-4: Environment - Compatibility levels in industrial plants for low-frequency conducted disturbances

While this parallels Section 2, it is a Technical Report, because for industrial plants, there is much more emphasis on case-by-case negotiation with the network operator. A disturbance level may be acceptable at one place in a network but not at another.

 

 

 

IEC TR 61000-2-5:2017

Electromagnetic compatibility (EMC) - Part 2-5: Environment - Description and classification of electromagnetic environments

This is an important reference; especially in the context of EMC for functional safety, where the maximum probable exposure to disturbances must be evaluated, down to a very low order of probability.

IEC TR 61000-2-6:1995

Electromagnetic compatibility (EMC) - Part 2: Environment - Section 6: Assessment of the emission levels in the power supply of industrial plants as regards low-frequency conducted disturbances

As for Section 4, this is largely about the terms for negotiation between supplier and user, on a case-by-case basis.

IEC TR 61000-2-7:1998

Electromagnetic compatibility (EMC) - Part 2: Environment - Section 7: Low frequency magnetic fields in various environments

These magnetic fields may affect anything electrical or electronic, simply by inducing unwanted currents in circuits.

IEC TR 61000-2-8:2002

Electromagnetic compatibility (EMC) - Part 2-8: Environment - Voltage dips and short interruptions on public electric power supply systems with statistical measurement results

This gives important information that can help to determine the immunity level required for a given product and a given environment.

IEC 61000-2-9:1996

Electromagnetic compatibility (EMC) - Part 2: Environment - Section 9: Description of HEMP environment - Radiated disturbance. Basic EMC publication

Another document that we hope never to have to refer to! But if your work can be said to include 'infrastructure', then these issues are vital.

IEC 61000-2-10:1998

Electromagnetic compatibility (EMC) - Part 2-10: Environment - Description of HEMP environment - Conducted disturbance

This one is in the same category as Section 10.

IEC 61000-2-11:1999

Electromagnetic compatibility (EMC) - Part 2-11: Environment - Classification of HEMP environments

And so is this one. (No jokes about the culture of illegal substances, please!)

IEC 61000-2-12:2003

Electromagnetic compatibility (EMC) - Part 2-12: Environment - Compatibility levels for low-frequency conducted disturbances and signalling in public medium-voltage power supply systems

This is a standard because it isn't about case-by-case negotiation.

IEC 61000-2-13:2005

Electromagnetic compatibility (EMC) - Part 2-13: Environment - High-power electromagnetic (HPEM) environments - Radiated and conducted

HPEM is 'High-Power ElectroMagnetic pulse', (which may be of natural origin and at or below ground level), while HEMP is 'High-altitude Electromagnetic Pulse', which might be due to a nuclear event or possibly the descent and disintegration of a large meteor.

IEC TR 61000-2-14:2006

Electromagnetic compatibility (EMC) - Part 2-14: Environment - Overvoltages on public electricity distribution networks

This is obviously an important subject; this has been realised only relatively recently - witness the products only a few years old that do not have any form of surge suppression at the power entry. In the early days, suppression components were prone to explode, due to their characteristics not being fully understood. It is also possible to (expensively) over-design if the threat level is over-estimated.

Things to come

Unless a hotter topic intervenes, next time we will look at the IEC 61000-3 series.

NKYS1710                              Date: 17-09-24                     © J. M. Woodgate 2017     (13-01)

Know Your Standards

by J. M. Woodgate B.Sc.(Eng.) C.Eng.  MIET SMIEEE FAES Hon FInstSCE MIOA

IEC 61000-3 series

As threatened last time, we continue our review with Part 3 of IEC 61000, whose Sections include two of the most important EMC standards, applying in Europe in support of the EMC Directive and in many other countries as well. After many difficulties, the first steps towards corresponding standards applicable in other countries, including those with 60 Hz supplies, have been taken by the publication of the 2017 amendment of IEC 61000-2-2 on applicable compatibility levels.

IEC TR 61000-3-1 (not published)

We start on a low note; in 1998 this was supposed to be a Technical Report giving an overview of the whole series. It was abandoned in 2011 after zero progress.

IEC 61000-3-2:2014

This is one of the two controversial emission standards on 'low-frequency conducted disturbances', those known to their friends (and enemies) as 'mains harmonics'.  It is a product-family standard, with a huge 'family', and applies to everything that has a household-type mains plug, or draws up to 16 A per phase. (OK, I know the risks of absolute statements - somewhere someone may make a product so abstruse that it would never be used on the public electricity supply, so doesn't have to meet this standard.)

It divides products into four classes, A to D, where Class A applies to most product types, Class B applies to mostly hand-held power tools, used for short periods only, Class C applies to 'lighting equipment', which has a complicated definition; it imposes strict limits because of the large proportion of the network load that is due to lighting, while Class D applies to computers and TV sets, which, unless they include mitigation measures, draw current from the mains supply as short pulses, whose low-odd-order harmonic currents are almost in the same phase for all products, so add arithmetically. The 3rd, 9th, 15th etc. add in the neutral wire of 3-phase and neutral distribution cables, and can cause severe overheating (theoretically the current can be 2.8 times the fundamental current). The 5th harmonic propagates into the Medium Voltage network in many countries, where it can excite resonance, which is very bad news for system overvoltage and reliability.

Classes A, B and D have each their own set of limits, but Class C doesn't; for some lighting products, the class A limits apply, for others, the class D limits and for yet others either a special set of limits or a 'special current waveform'. So there aren't unambiguous 'Class C limits' as such; one has to refer to 'table 1', 'table 2', 'table 3' or 'special waveform'.

The measurements involve quite a lot of data processing, so a special harmonic analyser is required, described in IEC 61000-4-7.

Current work on this standard includes a series of amendments to take new technology into account, notably LED lamps and new types of dimmers, which are new and controversial issues.

IEC 61000-3-3:2013+AMD1:2017

This is the other 'terrible twin' of 'low-frequency conducted emissions', with 61000-3-2. It is a product-family standard applying to everything that can be connected to the public electricity supply and draws up to 16 A per phase. What it limits are voltage changes (reductions only), due to inrush current and load current fluctuations, especially repetitive fluctuations that can cause lighting to flicker. A special measuring system is required to evaluate this, the 'flickermeter' specified in IEC 61000-4-15.

IEC TR 61000-3-4:1998

This deals with harmonic current emissions for products drawing more than 75 A per phase. It is advisory, because the connection of such products to the public supply always involves negotiation with the network operator. Before IEC 61000-3-12 was produced, it also applied to products drawing more than 16 A per phase.

IEC TS 61000-3-5:2009

This is a Technical Specification, of the type that is not intended to be converted to a standard. It deals with the same subject as 61000-3-3 but for products drawing more than 75 A per phase. The precise reason why it is a TS and not a TR is obscure, but, as for TRs,  it cannot be notified under the EMC Directive in Europe.

IEC TR 61000-3-6:2008

This Report is about harmonic emissions directly into the Medium Voltage (MV), High Voltage (HV) and Extra-High Voltage (EHV) networks. It is advisory because all such connections of loads are negotiated with the network operator.

IEC TR 61000-3-7:2008

This Report complements IEC TR 61000-3-6, in dealing with voltage fluctuations due to loads on MV, HV and EHV systems. It is, of course, advisory.

IEC 61000-3-8:1997

This standard specifies emission levels, frequency bands and disturbance levels for mains signalling ('ripple control'), which is mainly used by electricity suppliers, not in Britain but extensively elsewhere.  There are three frequency bands defined for use in Europe - 3 kHz to 9 kHz, 9 kHz to 95 kHz and 95 kHz to 148.5 kHz.  The upper band stops just short of the LF ('long wave') broadcast band in Europe. Controversy has recently arisen because some countries outside Europe want the bands extended to 500 kHz, because they do not have LF broadcasting. It isn't clear why different frequency ranges cannot be specified for different continents  or ITU Regions.

IEC 61000-3-9

This was intended to be a standard for emission limits for interharmonics (currents at frequencies not related to the power frequency), but a controversial alternative approach has been developed - measuring harmonic currents with a bandwidth equal to the power frequency, so that harmonics and any interharmonics are added together. This has been shown to result in equipment that does not cause any problem in practice nevertheless exceeding the limits, so a compromise has been developed that eliminates the need, at present, for work on a separate standard.

IEC 61000-3-10

This is intended to be a standard for emissions in the frequency range from the 40th harmonic to 9 kHz, but no progress could be made over many years, due to changing technologies and lack of data on which to base realistic requirements.  It is still in the programme of work, and a new group is at present assigned to work on it. Progress, however, is very slow.

IEC 61000-3-11:2017

This standard complements IEC 61000-3-3 for products drawing more than 16 A but less than 75 A per phase, and for products drawing less than 16 A per phase which cannot meet IEC 61000-3-5.

IEC 61000-3-12:2011

This standard complements IEC 61000-3-2 for products drawing more than 16 A but less than 75 A per phase. It takes a very different approach from that of  IEC 61000-3-2, basing limits on the ratio of the load impedance to the supply impedance.

IEC TR 61000-3-13:2008

This advisory Report is about emission limits for unbalanced loads connected to MV, HV and EHV systems.

IEC TR 61000-3-14:2011

This Report concerns the assessment of emission limits for harmonics, interharmonics, voltage fluctuations and unbalance for loads connected to LV systems.

IEC TR 61000-3-15:2011

This Report is about emission and immunity limits for dispersed generation systems - a complex matter. It was originally intended as standard, then as a TS and finally, considering that the technology is not yet mature, it remains a Report, but perhaps not for ever.

 At present, there are no more Sections of Part 3, but there will be in future. At present, work is at early stages for Sections 16 (Harmonic emissions of LV generators), 17 (Voltage changes and flicker of LV generators) and 18 (whose title is under discussion, but will be a TR on the characteristics of electricity supply systems that differ from the European model). Next time, we look at IEC 61000-5 series (since we already dealt with the 61000-4- series recently).