A Standard for the 90s: IEEE 

C62.41 Surges Ahead 

The Recent Upgrade of This Key IEEE Standard Reflects the 

Growing Interest Over Power Line Surges 

Francois D. Martzlofi National Institute of Standards and Technology, (301) 975-2409 

W ith each year that passes, we are relying more and 

more on electronics in our lives, at home, at work, for 

travel, for defense ... the list is endless. Reliability of these 

electronic systems is essential, and this in a context of increased sophistication which often brings about more susceptibility to disturbances. Thus, immunity to 

electromagnetic disturbances, including surges in the power 

line, is a must. 

Designers and users perform surge testing to verify that, 

indeed, their equipment is immune to these surges. The 

question, however, is what level of immunity must be 

achieved, since there are engineering tradeoffs to be made, 

as well as economic considerations. Depending on the type 

of equipment (its mission) and the location where it will be 

used, a moderate or very high degree of immunity is 

appropriate. To select the appropriate level of surge stress 

and to perform surge testing in a manner that will yield 

valid results while ensuring safety, reliable guidance is 

needed. 

Ten years after its first publication as IEEE Standard 587, 

the Guide on Surge Voltages in Low Voltage AC Power 

Circuits (now ANSYIEEE C62.41- 1980) has undergone a 

major transformation into a Recommended Practice format. 

From a guide proposing two basic waveforms to represent 

typical surges, the document now proposes consideration of 

two standard waveforms (the old friends of 1980) 

complemented by three additional waveforms, one a fast 

burst, the others longer, high-energy surges. 

A History of IEEE C62.41 

Actually, the occurrence of surges that led to the 

launching of a small working group in 1966 to develop 

IEEE 587 have not changed much, although the electronic 

equipment affected by surges as well as the 

standard-writing group have undergone considerable 

changes. The initial effort to provide guidance for 

designers on surges in low voltage circuits was started by 

Dave Bodle [I], who persuaded a small group of concern

fellows to seek a home in the IEEE Surge-Protective 

Devices Committee (a body which, at the time, was mos

concerned with the high voltage world of electric utilitie

This pioneer group set out to collect published data on 

surge occurrences and even circulated among its membe

set of six peak-reading surge counters donated by one 

sponsor to add to its data base. These were the days befo

the explosive development of disturbance monitors cum 

graphics. And so, IEEE 587 was born in 1980, with grea

expectations that it would be a useful guide for designers 

and users of electrical and electronic equipment. 

Alas, there were no other documents available to guide 

those users in selecting severity levels from the choice 

proposed by IEEE 587. In particular, the citation of 6kV 

being a practical upper limit for the occurrence of surges 

120-V circuits was soon misconstrued as implying a 

requirement that all equipment should be designed to 

withstand 6kV surges. Product specification sheets bega

to state 'meets IEEE 587,' forgetting the difference betw

a standard and a guide in EEE parlance. In the meantim

the guide was renumbered ANSIIIEEE C62.4 1, as part o

family of surge-related documents [2] but the '587' labe

has stuck and is even found in the model names of sever

commercial surge generators. 

In a first attempt to help users make sensible and corre

decision on surge testing, the IEEE working group 

developed a Guide on Surge Testing - ANSVIEEE 

C62.45-1987. The Guide provided information on how 

conduct reliable and safe surge tests ("Don't kid yoursel

don't kill yourself!"), also pointing out how to interpret t

concepts of locations categories proposed in the original 

document. However, the questions and misuse by some 

continued, so the working group resolved to update the 

guide. 

Compliance Engineerin
"-- - -. -- 

A Standard for the 90's ... 

Normally, IEEE procedures require a 5-year cycle of reaffirmation or revisi

but the challenge of reviewing new data and developing consensus on this 

subject stretched the work into ten years, culminating in a Recommended 

Practice that was approved early in 1991 and is now available from IEEE. Fro

a group of 12 people in 1980, the working group grew to 29 by 1990, reflectin

the growing interest about surge protection among users and manufacturers of 

electronic equipment. Reconciling the different points of view from the 

enlarged group has produced a new document that should receive even better 

acceptance than the original 1980 version and, hopefully, result in fewer 

Toward a More Useful Standard 

One of the first difficulties was to anive at a satisfactory agreement of what 

the word 'surge' means; to some a surge is a temporary increase in the AC lin

voltage. hatm mean in^ is now replaced by the term 'swell,' although a sizeab

fraction of the engineering community will continue to use the word surge wit

that meaning. 

Next came the issue of noise versus surges (spikes, etc.). How big must a 

voltage change be to become a surge? That issue was in fact not resolved; 

instead, a conceptual figure was included in the document to show the 

relationships among several parameters (see Figure 1) and thus leave the 

bottom end of the range open to appropriate interpretation depending on the 

circumstances. In addition, the single-value upper limit of voltages proposed 

the 1980 version has been replaced by a table featuring three levels for each 

waveform, according to the location category or the system exposure. The 

menu of waveforms proposed in the 1991 version is new and, hopefully, 

improved, and includes the following types: 

The 0.5 ps - 100 kHz Ring Wave, defined in the 1980 version, as standar

waveform. 

The Combination Wave, 1.2150 ps - 8/20 p, also from 1980, as standard 

waveform. 

The EFT Burst (5150 ns), adopted from IEC 801-4, as additional wavefor

A new 10/1000 ps Wave, for high-energy stress, as additional waveform

A new 5 kHz Ring Wave, for capacitor switching transient, as additional 

waveform. 

The rationale for proposing standard and additional waveforms is rooted in 

acceptance of the 1980 waveforms as being representative and useful, while 

recognizing that other waveforms may be encountered in specific cases and 

should be recognized. However, the wish for complete representation of all 

surges that may occur has to be tempered by economics and engineering 

judgment; hence, the split between standard (recommended) and additional 

(suggested). Figure 2 shows all five waveforms, and Table 1 presents a 

summary of the voltage and impedance values. The new waveforms are 

proposed in response to emerging concerns on surge occurring in specific 

environments. Thus, a brief discussion of these three new waveforms is in or

Additional Waveforms Address Emerging Concerns 

The EFT Burst has been developed by Technical Committee 65 of the 

International Electrotechnical Commission (IEC) to provide a screening test f

susceptibility to the fast transients that can be induced in power as well as dat

lines by the multiple re-ignitions occurring during the opening of a circuit by 

contactor. While this type of contactor is mostly found in industrial 

environments (the world of TC65), other systems can have the same exposure 

(at least until the day when all power switching will be done by bounce-free, 

Fall 

Circle Reader Se~ice #I7 
A Standard for the 90's ... 

restrike-free solid-state relays). The catch, however, is that 

this test waveform was proposed to evaluate immunity of 

equipment by a test procedure that involves coupling the 

burst into the equipment under test by a capacitance divider: 

the coupling capacitor and the internal capacitance of the 

equipment under test. It does not mean that the 1-4kV 

surges involved in this test necessarily occur in the power 

systems; what it means is that equipment that passes the 

high severity test will most likely be immune to what the 

real world does to connected equipment. One should not 

lose sight of this fundamental aspect of test standards; it is 

impossible to duplicate all possible occurrences in one test, 

but if a test can be developed so that equipment that passes 

the test has better field performance than equipment that 

fails the test, then the test is a valuable tool for reliable 

design. 

The 1011000 ps Wave has been proposed to provide a 

means to stress equipment with high-energy surges, such as 

those that can occur during major power-system fault 

clearing. The data base for that waveform is somewhat 

limited so a range of peak levels and source impedance is 

proposed, to be selected according to the particulars of the 

situation. As one check for reality, the energy deposition 

capability of this waveform is such that small varistors 

(14-mm diameter or less) in common use - by the millions - 

could only withstand a few applications of that surge. Thus, 

we know that such a high-energy surge does not occur very 

often. 

. EFFECT 

I 10 

MICROSECONDS MILLISECONOS SECONDS 

DURATION OF MM 

FIGURE 2: Simplified Relationships Between Voltage, 

Duration, Rate of Change and Their Effects on Equipment. 

(All figures in this article reproduced from IEEE Std 

C62.41-1991, "Recommended Practice on Surge Utilities i

Low-Voltage AC Power Circuits." Copyright O 1991 by 

the Institute of Electrical and Electronics Engineers, Inc., 

with the permission of the IEEE.) 

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Circle Reader Sewice #I8 

E Compliance Engineering 
100 kHz Ring Wave 

0 0 

0 10 40 w 10 TtME.pa too 

Combination Wave, Open-Circuit Voltage 

DURATION - 20~8 

0 10 m 10 "O TIME.p8 

Combination Wave. Short-circuit Current 

0 0 

0 20 10 a0 TIME. n* 

Waveform of a pulse in the EFT burst 

Waveform for the 1011 000 ys current surge 

1 0 100 zoo 300 

Waveform for 5 kHz Ring Wave 

FIGURE 2 

Fall 1
A Standard for the 90

s ... 

Location 

Categov 

At 

A2 

A3 

Sem 

Exposure ** 

Low 

Medium 

High 

Low 

Medium 

High 

Stendard Waveforms I .4 

100 kHz Combination EFT Wng Wave 

None 

30 None 

None 

ditional Waveforms 

lO/lam 

Ring Wave + W*** Q) W*" (0) 

None 

1.0 1 

1.3 0.25 

None 

1.0 1 

1.3 0.25 

None 

1.0 1105 

1.8 0.5 to 1 

None 

1.0 ltO5 

1.8 0.5 to 1 

C1 

C2 

C3 

Location Category A is end of "long" branch circuits. 

LOCatiOn Category B is service entrance and 'short" branch circuits 

Locatlon Category C is outside of building 

** System exposure levels reflects environment factors: lightning activity, power system switching, etc. 

... Voltage in per-unit of the peak of the mains voltage, added at the peak of the sine wave 

Table I: Peak Surge Levels (V) and Source Impedances (Z) in C62.41-1991. 

Low 

Medium 

High 

The 5 Hz Ring Wave has been proposed to represent the 

situation encountered near large power-factor correction 

capacitor banks. Switching transients in the range of 500 to 

1000 Hz can occur, with high-energy capability. In this 

case, the data base is rich in computer simulations and 

anecdotal recordings but it is difficult to make an accurate 

prediction for the general case, because the actual transients 

depend entirely on the local situation. It will be up to 

manufacturers and users to agree on a compromise between 

conservative overdesign wishes and economic viability of 

the design. 

Waveform Selection Supports International 

Harmonization Efforts 

None 

None 

None 

The waveforms presented in the new Recommended 

Practice document should also be a positive step toward 

harmonization with international standards. The 

Combination Wave is consistent with the conventional 

'impulse' typical of IEC surge testing; the ElT Burst 

represents the adoption of an existing IEC Standard. 

Conversely, the 100 kHz Ring Wave, long resisted by some 

of the IEC Committees, is beginning to gain a foothold in 

the IEC community. The 10/1000 ps Wave could be an 

alternative to the 10011300 ps surge 'under consideration' 

in some of the IEC TC 77 surge immunity drafts. (This 

10011300 ps surge is a varistor killer and, therefore, should 

not be considered beyond its original scope of application 

which is heavy industrial environments where faults are 

cleared by fuses(5)). The 5 kHz Ring Wave has yet to gain 

international recognition. 

To assist designers in making computer simulations, the 

Recommended Practice document provides equations for 

the waveforms, and tolerances are also specified. This 

detailed information might be better located in the Guide on 

Surge Testing but it was included in the Recommended 

Practice document until such time as a revised guide on 

surge testing will include it (that revision has just been 

initiated, and it will probably take another year before the 

revision is in print). 

Last but not least, the new Recommended Practice 

document has three appendices that offer tutorial 

discussions of the concepts used in the document, provid

information on the data base, and list almost 100 

bibliographic citations, with brief notes on the contents o

the papers. Thus, readers of the Recommended Practice 

will have on hand a short course on how to be prepared to 

deal with surges in low voltage AC circuits. 

Francois D. Martzloff is a member of C62.41 working 

group, and has been involved in surge protection issues fo

more than two decades. He has been at the National 

Institute of Standards and Technology since 1985 and can 

be reached at (301) 975-2409. 

The author acknowledges thefiveyear effort in consens

building by the members of the working group and other 

interested parties that made possible the revision of IEEE 

587 into a Recommended Practice. 

REFERENCES 

I. Bodle, D.W. et al. Characterization of the Electrical 

Environment, University of Toronto Press, 1976. 

2. C62: Complete Edition: A bound-book collection of 

the guides and standards on surge protection, publish

periodically by IEEE. 

3. Martzloff, F.D. & Leedy, "T.F. Electrical Fast 

Transients: Applications and Limitations," IEEE 

Transactions IA-26, Jan/Feb 1990, pp 151 - 159 

4. Feninmore, C, and Martzloff, F.D. "Validating Surge 

Tests by Field Experience: High-Energy Tests and 

Varistor Performance." Conference Record, IEEE4A

Annual Meeting, Seattle, 1990. 

5. Meissen, W. Uberspannungen in 

Niederspannungsnetzen, Elektrotechnische Zeitschrif

vol. 104, 1983. 

6 2 

10 2 

20 2 

Fall 1

None 

None 

None 

None 

1.0 1 

1.3 0.25