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Product Safety Newsletter •

What's InsideTheProductSafetyNewsletter

Vol. 8, No. 3 May-August 1995

Chairman’s Message ........................... 1

Officers of the PSTC’s ........................ 2

Letters to the Editor ............................ 3

Area Activities .................................... 4

Technically Speaking ......................... 5

News and Notes .................................. 6

News from the Internet ....................... 7

Institutional Listings ........................... 22

Chairman's Message

For some time, we have been discussing thefuture of the Product Safety Technical Committeein light of the organizational and operationalchanges requested by the EMC Society. I’m writ-ing this in advance of our Annual Meeting sched-uled for Wednesday, August 16th at the Interna-tional EMC Symposium in Atlanta. At that time,we will attempt to resolve as many of the issues aspossible. In the meantime, I would appreciatereceiving your comments on the following pro-posal.

Already we have heard from many of youwith your ideas for the best course of action. Theconsiderable majority favored continued affilia-tion with the IEEE, with most favoring the Tech-nical Council approach over a direct merger withthe TAB Environment, Health and Safety Com-mittee. The remainder of the suggestions favoredeither going independent (forming a new productsafety society) or merging with an existing non-IEEE safety group such as the ASSE or the NewEngland Product Safety Society (with whom wehave had a long association). What is the ap-proach we will be recommending at the Annualmeeting?

After reviewing the various arguments forand against, we are setting a course toward thecreation of an IEEE Product Safety Technical

Continued on Page 8


TheProductSafetyNewsletter

Chairman: Brian Claes Phone: (510) 659-6574Fax: (510) 659-6852

Vice Chair: Richard Pescatore Phone: (408) 447-6607 e-mail: [email protected]/ John McBain Phone: (408) 746-5016Treasurer: Fax: (408) 746-5551 e-mail: [email protected]: Murlin Montrose Phone: (408) 247-5715 email:[email protected]

Central Committee

Local GroupsChicagoChairman: John Allen Phone: (708) 238-0188Southern California/Orange CountyChair/Secretary: Charlie Bayhi Phone: (714) 367-0919Vice-Chair/Treas: Ercell Bryant Phone: (714) 589-0700PortlandChairman/ Scott Varner Phone: (503) 656-8841 e-mail: [email protected]/Treasuer: Scott VarnerSanta Clara ValleyChairman: Murlin Marks Phone: (408) 985-2400x2353 e-mail: [email protected] Chair/Program: Edward Karl Phone: (408) 986-7184Treasurer: Mark Montrose Phone: (408) 247-5715Secretary: Parviz Boozarpour Phone: (510) 527-7593SeattleChairman: Walt Hart Phone: (206) 356-5177 e-mail: [email protected] Chair: John Quigley Phone: (206) 226-1660Texas (Central)Chairman: Vic Baldwin Phone: (512) 990-6145Vice Chair Charlie GoertzSecretary/Treasurer: Daniece CarpenterColoradoChairman: Richard Georgerian Phone: (303) 417-7537 e-mail: [email protected]

Fax: (303) 417-7829

Editor: Roger Volgstadt Fax: (408) 285-2553 e-mail: [email protected] & Notes: David Edmunds (716) 422 6449 (fax) e-mail: [email protected] Editor: John Reynolds Fax: (408)526-8348 e-mail: [email protected] Layout: Kristin Eckhardt Fax: (804) 560-5342Subscriptions: Dave McChesney Fax: (408) 296-3256Institutional Listings: Ervin Gomez e-mail: [email protected]

Newsletter Committee

The Product Safety Newsletter is published bimonthly by the Product Safety Technical Committee of the Institute ofElectronic and Electrical Engineers EMC Society. No part of this newsletter may be reproduced without writtenpermission of the authors. All rights to the articles remain with the authors. Opinions expressed in this newsletter arethose of the authors and do not necessarily represent the opinions of the Technical Committee or its members. Indeed,there may be and often are substantial disagreements with some of the opinions expressed by the authors. Permissionto copy without fee all or part of any material without a copyright notice is granted provided that the copies are notmade or distributed for direct commercial advantage, and the title of the publication and its date appear on each copy.To copy material with a copyright notice requires specific permission. Please direct all inquiries or requests to IEEECopyrights office. Subscriptions are free and may be obtained by contacting Dave McChesney at 1865 Farndon Ave.,Los Altos, CA 94024


Letters To the Editor

We received the following letter from one ofour readers since our last publication. Please feelfree to contact the PSN either at the return addresson this publication, by fax at 408-285-2553 or by e-mail at either [email protected] (Product Safetyemail forum) or to [email protected]

To: Mr. Rich NuteJune 2, 1995

Your article “Two Measures, Two Levels”appearing in the March/April PSN has severalwell made points. “Measures” and “Levels” arevague terms in need of better definition.

You made mention of the hazards in Classi-fied Areas and 1 would call your attention to theslightly different approach put in use for suchHAZLOC designs. FM and NFPA both, alongwith the ISA, when considering the hazards ofclassified areas, use the “two fault” approach.oward protection for safety. The hazard is pre-sumed to exist and then analysis is based uponwhat two faults may occur that allow ignition ofthe hazard. Also, that the presence of the hazardwhere it should not be can be taken as one fault.With emphasis directed toward identification offaults that result in a dangerous condition, whetherthe hazard is present or not becomes a non-issue.Fhis is another approach toward the doublesafety protection concept for your consideration.

I have enjoyedyour articles and lookforward to manymore.

Regards,John H. Rolleston,Mettler-Toledo, Inc.

The author’s response:

The comment is a good one, and should bepublished.

Rich Nuteauthor,Technically Speakingtel: (34) 3-582-13-89fax: (34) 3-582-25-15e-mail: [email protected] �

The Product Safety NewsletterCommittee is looking for someone

interested in writing the AreaActivities column. If interested

contact Roger Volgstadt, Editor,at (408) 285-2540.


Continued on page 10

Area Activities

by John Reynoldsvoice: (408) 526-8364; fax: (408) 626-8348e-mail: < [email protected]> [email protected]

The February 28,1995 meeting of the SantaClara Valley PSTC featured a talk by Mr. DennisWard of CKC Laboratories. Mr. Ward discussedthe “CEMarking-EMC Directive” and the severalroutes to obtaining compliance with CE mark foremissions and immunity testing ofITE which aremandatory on January 1, 1996.

The March 28, 1995 meeting featured a talkby Mr. Glenn Koehler, P.E. of Lockheed Missiles& Space Co. Mr. Koehler made a presentation on“Applying System Safety to Products.” His talkcovered the value of applying system safety engi-neering techniques to product facilities for theexplicit purpose of protecting products from dam-age during testing operations.

The April 25, 1995 speaker was Ms. Shan-non McElyea of NetCom who spoke on the Internetand services available through NetCom.

Our May 23, 1995 speaker spoke on Field.Evaluation Procedures.

June 20: Wayne Menuz of UnderwritersLaboratories, Inc., spoke onMexico certificationO(NOM marking).

The March 22 meeting featured Mr. NickMaalouf CSA’s VPofOperations US & Europe.

Mr. Maalouf answered some of the groupsquestions about CSA services. Answers includedresponse to such questions as

- Why is CSA Category Test Data notacceptable for NRTL approval?

- Will it ever be acceptable for NRTLapprovals?

- What can CSA do to ease and improveUL’s acceptance ofCSA CertifiedComponents?

- When does CSA plan to have e-mailaccess to all engineers?

- Is Internet access planned? If so, when?

For a response to these and other questions,request a copy of the last two issues of the NorthEast Product Safety Society newsletter by con-tacting Art Michael at (203) 344-1651. The

Santa Clara Valley Chapter

Northeast Product Safety Society


Technically Speaking


Normally, this column addresses technicalissues in the field of safety. Usually, it does notaddress issues in safety standards. This issue’stopic is rather unique because this columnaddresses safety requirements for a non-safetycritical device, “operational” or “functional” in-sulation.

IEC 950 specifies requirements for insula-tion in ALL circuits, including extra-low-voltage,and SELV circuits.

These requirements are of interest becausethe principal purpose of insulation is protectiongainst electric shock.

(A secondary safety purpose of insulation isprotection against short circuits which couldlead to conductor or component overheating andfire.)

The insulations which are critical toprotection against electric shock are defined as“basic,” “supplementary,” and “reinforced.” (Inthis article, I refer to these as safety insulations.)

IEC 950 includes a fourth insulation, “op-erational insulation.”

Copyright 1995 by Richard Nutevoice: (34) 3-582-13-89; fax: (34) 3-582-25-15e-mail: [email protected]

“Operational insulation” is defined as theinsulation needed for the correct operation of theequipment. A note accompanying the definitionstates that operational insulation by definitiondoes not protect against electric shock. The notecontinues by saying that operational insulationmay serve to minimize exposure to ignition andfire.

Examples of “operational insulation”would be all of the spacings and solid insulationsin primary and secondary circuit that are notsafety insulations, and all of the insulationswithin EL V and SEL V circuits.

IEC 950 specifies spacings (clearances andcreepage distances) for all four insulations (basic,supplementary, reinforced, and operational) forboth primary and secondary circuits.

Therefore, for IEC 950, you must considerevery spacing and every solid insulation in everycircuit throughout the entire product.

Operational Insulation in IEC 950


News and Notes


ANOTHER VERSION OFELECTRONIC STANDARDS

UL has introduced a new version for all of itsstandards that permits Highlighting, Bookmarking,Searching and Hypertext Link. Windows 3.1 orhigher and 8MB RAM is recommended. No othersoftware is needed. Prices vary according to thestandard; UL 1950 costs $ 425.00 for companieswith UL Listing/Recogntion and $ 530.00 fornon-clients. Included is a 3 year subscription toUL’s subscription service which includes receiptof bulletins and standard updates. Contact An-drea Briesch, phone (708) 272-8800 Ext 42983for further information and pricing.

JURORS ABSOLVE KEYBOARD

[The following information was extractedfrom the March 9, 1995 edition of the San JoseMercury News - Ed.]

A Minnesota jury decided [recently] thatIBM was not liable for injuries a former highschool secretary said were caused by the design ofits computer keyboards. ... The case has beenclosely watched by makers of office equipmentand lawyers around the country for thousands of

clerical workers who be-lieve that poorly de-signed data-processingequipment has led toan epidemic of neck,shoulder, arm andhand ailments collec-tively known as re-petitive stress inju-ries, or RSI.

This was the first case against IBM or Appleto reach a jury. “The jury rejected every argumentthey advanced, including their claims that thekeyboard design was defective, that we had a dutyto warn users and even that the plaintiff had anyinjuries associated with keyboard work,” saidMichael Cerussi, IBM’s lead attorney in the RSIcase.

The plaintiff, Nancy Urbanski, 30, claimedthat any act requiring modest hand strength, frombrushing her hair to opening jars, had becomeunbearably painful as a result of her work on IBMand Apple computers from 1989 to 1991 as asecretary and registrar at the school in Eagan,Minn.

IBM argued that there is no credible scien-tific link between keyboard injuries and keyboarddesign. RSI studies show that regular rest breaksand careful placement of keyboards can preventsome injuries, but injury rates also appear todepend on a wide variety of factors, from thehealth habits of workers to their attitudes towardtheir jobs.

IBM charged that Urbanski was a disgruntledemployee.

by Roger Volgstadtvoice: (408) 285-2540 fax: (408) 285-2553e-mail: [email protected]



You may recall reading in theJanuary /February issue of the Prod-uct Safety Newsletter that the IEEEis sponsoring an on-line productsafety forum. Those with questions,comments or news of general inter-est about product safety can posttheir messages to over 175 productsafety professionals world-wide and,when requested, receive back valuable commentsand advice. Anyone with access to e-mail over theInternet can participate (See instructions on page20). Great product safety news and advice areavailable.

Since not everyone has access to the Internet,or those who do may not see every message, we’llbe featuring highlights from the forum in this andfuture editions of the PSN. To whet your appetite,please sample the following.

IS SAFETY CERTIFICATIONMANDATORY?

Rich [Nute] mentioned the following areasin the United States which legally require NRTLapproval:

Suffice it to say that if your product doesnot have NRTL certification, then it is not “le-gal” in many markets, including Los Angeles,San Francisco, Oregon, Washington, Chicago,and New York City. If it does have NRTL, thenit will likely be “legal” everywhere.

Rich is giving examples of known areas that

require NRTL approval.The following is a response

from Tom Castino, President ofUL, when asked by the NortheastProduct Safety Society (NPSS) atour June 23, 1993 meeting wheresafety certification is mandatory.

The question was: “WouldUL please supply a list of USA

states/regions which legally require agency [certi-fication organization] approval. In 1984 ULprovided the following list: Oregon, Washington,Pennsylvania, Maryland, Florida, Los AngelesCounty and for some product categories in CookCounty (Illinois/Chicago). .. Please provide anupdated list, based on non-commercial catego-ries” .

UL Response (From UL’ s February 2, 1994letter to the NPSS):

“Since 1984, the USA states/regions whichlegally require agency approval has grown toinclude all of the above areas plus North Carolina,Rhode Island, and Virginia. However, all of thesestates also have a legislative or administrativeprocedure for adopting national building codes orcodes such as the National Electric Code (NEC)”.

To summarize the list, the areas in the UnitedStates which legally require agency approval(NRTLs), according to UL, are:

- Oregon- Washington- Pennsylvania

News from the Internet


Council. This agrees with the majority responseand with previously stated PSTC objectives. Asdescribed below, there are considerable challengesahead of us to make this endeavor successful,since some critical attributes of our existing op-eration are not an exact fit within the IEEETechnical Council model. However, if we aresuccessful in creating the Technical Council op-eration that we envision, we will emerge moreeffective that ever. The challenge that lies ahead isto retain the essential programs of the existing TC-8 while expanding our operations and workingwithin the structure of the IEEE.

What will emerge from all this restructuringwill be two separate and distinct entities: a restruc-tured TC-8 and a new Product Safety TechnicalCouncil.

EMC TC-8

At the direction of the IEEE Society, EMCTC-8 will be restructured as a traditional techni-cal committee within the EMC Society, focusingon Electrical aspects of product safety. The tech-nical committee will have approximately five toten EMC Society members and will be devoted toannual Symposium-related events and standardsdevelopment.

With regard to Symposium activities, thecommittee will coordinate preparation, reviewand presentation of technical paper sessions andworkshops. Committee members are obligated tomeet face-to-face annually at the Symposium withinterim coordination and communication as needed.The August 16th meeting will focus on restructur-ing, goals, membership and leadership selec-tion.

Product Safety Technical Council

The new TC-8 will carry on only a smallportion of the activities presently conducted underthe existing TC-8. For the rest of these activitiesto both continue and expand within a TechnicalCouncil environment, we will be required to “re-invent” the Technical Council format and scope asit presently exists within the IEEE. As discussedin previous newsletters, technical councils areorganizations formed by two or more IEEE Soci-eties to address areas of shared interest, but wherethere is insufficient critical mass to spawn a newsociety.

Presently there are two Technical Councilswith the IEEE, formed to create publications orsponsoring symposia. The only members of theTechnical Council are those appointed by thesponsoring Societies to serve as the “Board ofDirectors.” The beneficiaries of the TechnicalCouncil activities are members of the affiliatedSocieties and others who subscribe to its publica-tions or attend its events.

This structure and scope is quite limited inview of our present organization and activities.Some present attributes not in the scope of aTechnical Council include:

We have several local groups with ties tolocal EMC Society chapters and the regionalIEEE organizations. We believe it is importantboth to foster creation of new groups interested inproduct safety and to improve support for existingones. We anticipate these groups will have the fullsupport of and cooperation with local chapters ofsupporting Societies.

We publish a product safety newsletter,but many of our newsletter subscribers are not

Chairman’s Message, Continued From Page 1

1

2


IEEE EMC Society members (although all offic-ers and chapter leaders are). While publicationsubscriptions may be made available to non-IEEEmembers, we expect our other services are ofsufficient value to attract many to IEEE mem-bership. Presently, we have over 1200 indi-viduals affiliated with our groups as newslet-ter subscribers and this number is increasing.

We report to a single Society and itsleadership, fostering continuity and a more con-sistent foundation for growth. We believe thatthere needs to be a core constituency within theTechnical Council to ensure continuity as Soci-ety-appointed representatives rotate in and out ofCouncil membership.

To proceed with the formation of the Tech-nical Council, a draft proposal will be developedin cooperation with those IEEE Societies mostinterested in sponsoring the Council. In view of theaugmented scope of the proposed Product SafetyTechnical Council, we anticipate that greater ef-fort will be required to secure ratification thanwould otherwise be the case.

In conclusion, we have a lot of work aheadof us. Your input and participation is requested. Ifyou can attend the Annual Meeting at the Sympo-sium, please come and be prepared to contribute toour planning. In the meantime, you can respondvia any of the following:

- Newsletter Editor(VolgstadCRoger@ @Tandem.com)

- E-mail to the EMC-PSTC Forum (emc-pstc@ @ieee.org) or

- Brian Claes (via fax: 1-510-659-8260or e-mail at bclaes@ @aol.com)

See you in Atlanta!Brian Claes �

IEEE 1995 INTERNATIONALSYMPOSIUM ON

ELECTROMAGNETICCOMPATIBILITY

Atlanta Marriott MarquisAugust 14-18, 1995

SYMPOSIUM OVERVIEW

Exhibit Hours:

Tuesday, August 159 am to 5 pm

Wednesday, August 168:30 am to 5 pm

Thursday, August 178:30 am to 5 pm

Registration:

Sunday, August 134 pm to 8 pm

Monday, August 148 am to 8 pm

Tuesday, August 157:30 am to 4:30 pm

Wednesday, August 167:30 am to 4:30 pm

Thursday, August 177:30 am to 12:00 pm

Friday, August 187:30 am to 9 am

3


March 31,1995 meeting of the ProductSafety Technical Committee of Central Texaswas held at the Hyatt Regency Austin. This wasa special meeting with the EMBS Chapter, EMCSociety and EMC Society Board of Directors.The Program was a panel discussion of theProblems of EMI Susceptibility in Medical Equip-ment. The panel consisted of Edwin Bronaugh,Dr. Glenn Bell and David Kilpatrick. Moderatorwas Dan Hoolihan.

Substantial public attention has recentlybeen directed to the issue of susceptibility (therelative lack of immunity) of medical equipmentto interference sources in the hospital and otherenvironments. Of special concern are the emis-sions of cellular phones in close proximity todevices. The Food and Drug Administration(FDA) is actively reviewing the issue and aspecial center has been established at the Univer-sity of Oklahoma to address it. Dan Hoolihan isa prominent figure in the area and represents theEMC Society on these Issues.

This chapter has provided us with the fol-lowing news items:

UL San Diego Office - Underwriters Labo-ratories has opened up a Local Engineering Ser-vices (LES) office in San Diego. The office islocated in northern San Diego, in the vicinity of1511805 interchange. The contact and specific

location is as follows:

Bill MikkawiUnderwriters Laboratories, Inc.10040 Mesa RimSan Diego, CA 92121-2912Phone (619) 546-0908FAX (619) 546-1745

2. NOM - As a follow up to our discussionregarding NOM Certification, enclosed pleasefind a document that is being distributed cour-tesy of Jim deVries, Manager Dell Product SafetyDepartment. This information was received viathe Internet from PSTC e-mail thru IEEE.

3. Programs - Thanks to Neil Koigawachiof Ca1Comp for his excellent presentation on theEPA Energy Star Registration.

May 2: MSDS Generation, by GabrielRoy of CalComp

June 6: What if your Safe Product Isn’t,by Charlie Bayhi of CPSM

Future meetings:

July 11: Economic Espionage (Tentative),by the Federal Bureau ofInvestigation

Well that’s all folks. Let me hear more fromyou. Those groups that I haven’t heard fromshould call, write, fax, or e-mail.

Best regards,JohnReynolds �

Central Texas

Area Activities, Continued From Page 4

Orange County/Southern California Chapter


SECOND CENELEC REPORT ONNATIONAL IMPLEMENTATION

OF EUROPEAN STANDARDSPUBLISHED

CENELEC, the European Committee forElectrotechnical Standardization, has just pub-lished the second edition of its Catalogue on“National Implementation of European Stan-dards.”

According to CENELEC rules, Europeanstandards are to be implemented in CENELECmember countries by giving it the status of a

national standard, either bypublication of an identicaltext or by endorsement.

This unique referencetool, compiled in Decem-ber, 1994, lists the na-tional implementation byCENELEC members of

more than 500 European standards(EN’s). The publication, designed for use inindustry and by exporters, gives exact nationalreferences for European standards.

The 270 page National ImplementationCatalogue can be purchased directly from theCENELEC Central Secretariat, rue de Stassart35, B-1O50 Brussels. Price: BEF 5000 (postageand handling included within Europe). The publi-cation is also for sale through the NationalElectechnical Committees, members ofCENELEC.

USING THE CE MARK

[The following two articles are extractedfrom the M.A. Lamothe and Associates Inc. /Ultra Tech Engineering Labs Inc. newsletter, “Ap-provals Review”. Subscriptions are free andavailable by calling 905-877-2203. The editorwishes to thank Lamothe and Associates andUltra Tech Engineering Labs for their support ofthe PSN. - Ed.]

There has been a significant degree of con-fusion regarding when you can start using the CEmarking and when it is mandatory for use inEurope.

The CE marking can not be used before the“possible from” date and must be used from the“Mandatory By” date shown in the table below.

You will note that most products will have tocomply with more than one directive and the datesfrom each directive will need to be considered.

The Low Voltage directive is generic andapplies unless there is a specific directive coveringyour type of product.

Remember that the CE marking is not acertification mark; it is your ‘statement’ that youmeet all of the applicable requirements in thedirectives that apply to your product. Most com-

Continued on Page 18

News and Notes, Continued From Page 6

Directive Category Possible Mandatory From

72/23/EEC Low Voltage 1995/01/01 1997/01/01 89/336/EEC EMC 1992/01/01 1996/01/01 91/263/EEC Telephone 1992/11/06 1997/01/01 93/42/EEC Medical 1995/01/01 1998/06/15


Some examples of operational insulationspacings (pollution degree 2) in primary andsecondary circuits are:

Because of these spacings requirements,IEC 950 says that many printed wiring boardinsulations for the bulk dc in the primary ofswitching-mode power supplies must have atleast 4.0 mm between conductors. This is morethan that required for primary-to-ground creep-age distance, 2.5 millimeters!

IEC 950 says that SEL V circuits on printedwiring boards must have at least 1.2 millimetersbetween conductors. If we were stuck with thesedimensions, then we could never use SMTdevices!

These spacings requirements provide manydesign constraints, especially as our products getsmaller and smaller, and require smaller andsmaller spacings.

Fortunately, IEC 950 provides some testand constructional alternatives to these dimen-sions.

The first alternative is to test the spacingswith a dielectric strength test.

This is a good alternative because therequired spacings are very much larger than theactual breakdown distances. Let’s look at someexamples.

For 350-volt dc primary and secondary cir-cuits, the test voltage would be 1500 volts rms.For the ELV and SELV circuits, the test voltagewould be 500 volts rms.

Upon review of IEC 664, we find that 1.1mm will withstand 1500 volts, and 0.1 mm willwithstand 500 volts.

These data suggest that creepage distancesvery much smaller than the required creepagedistances will pass the dielectric strength test.

So, all we need do is, for each voltage, findthe smallest spacing on the board, and test it. ForEL V and SEL V circuits, if the spacings are notless than 0.1 mm, then we can expect to pass the500- volt dielectric strength test. This will qualifyall the EL V and SEL V spacings on the board.Similar tests can be done for each voltage greaterthan ELV.

The second alternative is to short-circuiteach insulation that is less than the requiredspacing.

This would be an inordinate amount oftesting if each spacing had to be tested. Fortu-nately, IEC 950 specifies only two conditionswhen such testing must be performed. This cutsdown the testing to a reasonable amount.

The first condition is where short circuit-ing would cause overheating of a material andthereby create a risk of fire. A short-circuit, bydefinition, is zero ohms and cannot itself be a riskof fire. The short -circuit testing specified in IEC950 tests for heating in relatively low impedancesin the source providing the current into the short-circuit. Usually, this will be the power supply orpower distribution of the electronic equipment.

So, depending on resistances in the circuits,you may be able to conduct one short-circuit testwhich will maximize the heating in the powersupply and power distribution circuits.


Continued

Circuit Working Voltage

Clearance Creepage Distance

Primary 250rms 1.7 mm 2.5 mm Primary 350 dc 1.7 4.0 Secondary 350 dc 1.6 4.0 Secondary ELV, SELV 0.7 1.2


The second condition is where short-circuiting would cause thermal damage to oneof the safety insulations, basic, supplementary,or reinforced. In low-voltage secondarycircuits, these insulations would be the isolatinginsulations in the isolating transformer. So, ashort-circuit at the output of the transformer orthe power supply will cause the maximum heatingof the primary-secondary (safety) insulations.

So, short-circuit testing is not as onerous asit first seems.

The third al-ternative is an ex-emption to bothdielectric testingand short-circuittesting. If thematerial thatcould be over-heated during theshort-circuit testis V-l or better, then short-circuit and dielectricstrength testing is exempted.

Since circuit boards usually are V-1 orbetter, and wire insulation is V-1 or better, andsince transformer insulations are usually V-1 orbetter, often testing is not required.

Furthermore, elsewhere in the IEC 950standard, use of V-1 materials is encouraged forall insulations and wherever there is a chance ofoverheating.

So, after all this discussion, we discoverthat, for the most part, we can ignore spacingrequirements for operational insulations, includ-ing most of those in primary circuits ofswitching-mode power supplies.

What do these operational insulation (spac-ing) requirements and alternative tests and con-structions buy in terms of product safety?

Let’s first examine the purpose of spacings

requirements. The spacings requirements in IEC950 are loosely related to IEC 664. The object ofIEC 664 is to prevent solid insulation failureunder normal operating conditions. IEC 664 tellsus that normal operating conditions include thetransient overvoltages on power lines.

(The solid insulation in question is bothbulk solid insulation and surface -- creepage --insulation. Air insulation can be allowed to failas air is a renewable insulation. The failure of air

insulation is notpermanent andusually incon-sequential to thesafety of a prod-uct.)

IEC 664,being a basicsafety standard,is principallyconcerned with

dimensioning or otherwise protecting safetyinsulations against failure due to the normaltransient overvoltages that may be transmitted via thepower line to a product.

When spacings requirements are applied tooperational insulations, the presumption ismade that (1) the solid operational insulationis indeed subject to transient overvoltage, and(2) the solid operational insulation will not fail inthe presence of transient overvoltages. Preven-tion of failure of operational insulation presumesthat the failure of operational insulation will leadto an unacceptable safety situation.

Since the safety insulations are indepen-dently addressed, and since safety insulationsfully preclude electric shock, the unacceptablesafety situation implied by the failure of

“IEC 664, being a basic safety standard,is principally concerned with dimensioningor otherwise protecting safety insulationsagainst failure due to the normal transientovervoltages that may be transmitted via thepower line to a product. “

Continued on Page 19


panies are choosing to have their products testedand certified by an independent agency to ensureunfettered access to their chosen markets.

The CE marking and other logos are avail-able on disk in both Corel Draw and WindowsTrue Type font formats.

NOTIFIED VS. COMPETENT BODIES

Confusion often exists over the use of theterms ‘Notified Body’ and ‘Competent Body’ invarious references to European approval require-ments. There is no functional difference betweenthe two bodies.

The term ‘Competent Body’ is used in theEMC directive and, as such, you must use a‘Competent Body’ for all approvals required un-der the EMC directive. The ‘Competent Body’may appoint an affiliated test lab.

‘Notified Bodies’ and ‘Competent Bodies’are appointed by the government of the EU coun-try in which they are located and ‘Notified’ to thecentral bureaucracy in Brussels for inclusion inthe official listing of bodies who are competent toconduct the tests in question.

Each body is ‘Notified’ for specific productcategories (Telephone, Information Technology,etc.) and specific types of test (Safety, Ergonom-ics, etc.). You may have to go to more than onebody for a complete set of tests for any givenproduct.

OSHA REVERSES POSITION ONNRTL POLICY

[The following information comes from theTMO Update, published by the Marlet Organiza-tion, Ridgefield, CT. Subscriptions are $ 90.00/year and available by calling 203-438- 3801 - Ed.]

NRTL accreditation program... having per-formed on-site assessments and administrativereviews of the certification programs of the 5 year“grandfathered” organizations, UL and FM, pro-vides a Notice of Interpretation to allow UL andPM to continue to engage in programs currentlyemploying procedures denied to other OSHA ac-credited NRTL’s. OSHA has now reversed itsprevious positions and invites currently recog-nized NRTL’s as well as new applicants to requestapproval for any of these acceptable procedures.

As fully described in this clarification notice, newly acceptable procedures fall within oneor more of the following:

[of special interest to our readers:]

1. Acceptance of testing data fromindependent organizations otherthan NRTL’s.

2. Acceptance of witnessed testing data;3. Acceptance of testing data from

non-independent organizations;4. Acceptance of evaluation data from

non- independent organizations(requiring NRTL review prior tomarketing);

5. Acceptance of continued certificationfollowing minor product modificationsby the client;


Continued


6. Acceptance of product evaluations fromorganizations that function as part ofthe International ElectrotechnicalCommission Certification Body (IEC-CB) Scheme; and

7. Acceptance of services other than testingor evaluation performed bysubcontractors or agents.

Certain procedures are unacceptable. In-cluded among these are manufacturer’s self-declaration, client self-certification, and othersimilar procedures that permit non-NRTL’ s todetermine conformance with the product stan-dard, i.e. certify the product”

NEW UL MAGAZINE

UL has a new magazine-style publicationentitled “On the Mark”. It is “...dedicated togetting the pertinent information to UL’ s custom-ers and others interested in conformity assess-ment” The magazine will be discussing newprograms, new Listing categories and new devel-opments for the industries served by UL in theUS, well as in other countries around the globe.

Subscriptions are available upon requestContact Carole Feil, Underwriters Labo-

ratories, Inc. 333 Pfingsten Road, Northbrook,IL 60062 or phone (708) 272-8800, ext 42068.

NATIONAL ELECTRICALSAFETY MONTH

May was National Electrical Safety Monthaccording to the National Electric Safety Founda-tion (NESF). The theme of the campaign was“The Four Seasons of Electrical Safety,” empha-

sizing the need for year-round Electrical safety.NESF is a not-for-profit organization started

in July, 1994. The roots of NESF can be traced toan effort in 1991 by the Consumer Product SafetyCommission (CPSC) and the National ElectricalManufacturers Association (NEMA) to work to-gether to promote consumer awareness of Electri-cal safety. Underwriters Laboratories Inc. (UL)joined the effort in 1992 and the OccupationalSafety Health Administration (OSHA) joined in1994.

For more information about National Elec-trical Safety Month, or about NESF, contactNational Electrical Safety Foundation, 2101 LStreet, NW, Suite 300, Washington, DC 20037,or phone 202-457-1962.

UPDATED PUBLICATION TO LISTCERTIFICATION ORGANIZATIONS

The Standards Code and Information Pro-gram of the National Institute of Standards andTechnology (NIST) has awarded a contract to theMarley Organization, Inc. (TMO) to revise andupdate NIST Special Publication (SP 774) en-titled “Directory of U.S. Private Sector ProductCertification Programs”. NIST SP 774 was lastpublished in Dec., 1989 and included informationon the name and purpose of each organization, thetypes of products certified, and the steps involvedin the certification scheme. The revised directorywill add to these elements a pictorial of eachorganization’s certification mark. More informa-tion about the directory can be obtained by con-tacting the Marley Organization at 203-438-3801.Copied By: VOLGSTADT_ROGER @ESP

Continued


SINGAPORE GREEN LABELINGSCHEME

[The following information is provided viaManning I. Rose of AT&T Global InformationSolutions [email protected] - Ed.]

The Singapore Ministry of the Environmentintends to award the green label to personal com-puters (PC’s) which are energy-efficient. Thefollowing is the draft qualification criteria forenergy-efficient PC’s.

To qualify, a personal computer should beequipped with a power management feature thatminimizes electricity consumption when it is leftidle. The draft qualifying criteria for the differentcomponents of personal computers is shown be-low.

There are some 400,000 personal computersat workplaces [in Singapore] and the number isincreasing. Study shows that personal computersin workplaces are usually switched on throughoutoffice hours although they are used about a tenthof the time. An ordinary personal computerconsumes between 150 and 300 watts of electric-ity when switched on. On the other hand, apersonal computer with a power managementfeatures uses 60 Watts or less when it is idle.

The Green Labeling Scheme, launched inMay 1992, now includes 18 product categories.To date, 338 products have been awarded theGreen Label.

The Ministry welcomes comments on thedraft qualifying criteria. The comments will beconsidered by an Advisory Committee before thequalifying criteria are finalized. Unfortunately,comments should have reached the following ad-dress before May 31,1995. However, questionsand comments can still be addressed to:

Secretariat of The Singapore GreenLabeling Schemec/o Waste Minimization DepartmentMinistry of the Environment,Enviro Bldg #20-0040 Scotts RoadSingapore 0922 Fax 7354297

DRAFT QUALIFYING CRITERIA FORENERGY EFFICIENT COMPUTERS

- Electricity Consumption when thecomponent is idle.

- System Unit / Computer Monitor:30 Watts or less

- Computer system with Built in Monitor:60 Watts or less

a) System Unit: Comprising amother board with centralprocessing unit, CPU, power unit,hard disk drives and floppy diskdrives.

b) Computer Monitor: ExternalMonitor or Computer screen.

c) Computer System with built-inMonitor: Comprising a System.Unit and Monitor that is includedin the computer casing or cabinetand power through the SystemUnit.

Continued


OSHA REPORT

[The following information, written by SteveLohr, was taken from the 1995 New York NewsService- Ed.]

Bowing to pressure from Congress and busi-ness groups, the Clinton administration has de-cided not to issue regulations to protect workersfrom repetitive strain injuries, government officialssay.

Hundreds of thousands of American work-ers, from meat packers to computer programmers,are afflicted with repetitive strain injuries eachyear.

The fast-growing problem worried govern-ment officials as far back as 1990, when the Bushadministration told the Occupational Safety andHealth Administration, known as OSHA, to be-gin to develop a so-called ergonomic standard toprotect workers.

While the risk is greater in factories, repeti-tive strain injuries have become a big source ofinjuries in offices. As the nation shifts increas-ingly to a service economy, roughly 40 millionpeople - more than 40 percent of the work force-now work on computer keyboards.

As part of their campaign to curb federalregulations, the conservative Republicans whotook control of Congress in November took aim at

the push by OSHA for ergonomic rules.Ergonomics is a discipline that tries to designjobs and tools to fit the physical and psycho-logical limits of people.

Led by Rep. Tom DeLay, R- Texas, theHouse majority whip, the Congressional con-

servatives attacked the ergonomic initiative ofOSHA as precisely the kind of government regu-lation that should be stopped - costly and time-consuming for business, based on good intentionsbut mushy science.

Indeed, the science behind ergonomics doesnot supply neat cause-and-effect answers. Sug-gested risk factors extend beyond the job to in-clude stress at home, exercise routines and vita-min deficiencies.

In their bid to stop the ergonomic rules, theRepublicans were backed by powerful businessgroups like the National Federation of Indepen-dent Business and the National Association ofManufacturers, which formed a Coalition on Er-gonomics to organize the opposition.

OSHA is an executive agency, so it can issueregulations without Congressional approval. Still,Congress can apply plenty of pressure. DeLay, forexample, tacked an additional $3.5 million - theestimated cost of the OSHA ergonomics program- onto the agency’s budget cuts.

Yet more important, it seems, is the Clintonadministration’s reading of the anti-regulatory

UL AND MEXICAN SAFETY AGENCYENTER AGREEMENT

UL and NYCE (Normalizacion YCertificacion Electonica) of Mexico announcedMay 16th an agreement to work together toprovide manufacturers with safety certificationsfor North America.NYCE, based inMexico City, is ac-credited to issue cer-tification for elec-tronic products thatmeet the regulations of theSecretaria de Comercia yFomento Industrial (SECOFI), the Mexican gov-ernment body responsible for product safety regu-lations.

Continued


mood in Washington. Faced with an election yearin 1996, scarce political capital is not going to bespent on the OSHA rules, especially if the busi-ness groups are firmly opposed.

In a statement to be released Sunday, JosephDear, the assistant secretary of labor who headsOSHA, noted that 700,000 Americans sufferedfrom work-related musculoskeletal disorders anddiscussed the fate of the ergonomic standard pro-posed by the agency.

“In the face of Congressional intervention inOSHA standard setting,” Dear said, “it is not nowpossible to publish a standard which has thebreadth necessary to attack this problem.”

Last week, Barbara Silverstein, the specialassistant for the OSHA ergonomic program, leftthe agency.

Ms. Silverstein, an ergonomics expert onleave from the Washington State Department ofLabor, joined OSHA in November 1993 to workon the federal standard.

“Because of the political pressure from Con-gress, OSHA cannot publish an ergonomic stan-dard - it’s not going to happen,” Ms. Silversteinsaid last week.

Ms. Silverstein said she was leaving for avacation, after which she would return to work asa senior official in the Washington labor depart-ment and as an adjunct professor at the Universityof Washington.

In recent months OSHA has pared back itsergonomic standard to try to make it more palat-able to business. The latest proposal emphasizeseducation and prevention for companies morethan punishment for offenders.

“In the end,” said Neal Taslitz, executivedirector of the Repetitive Strain Injury Founda-tion, a nonprofit organization, “the OSHA pro-posal was mostly a program of required educationto try to prevent this epidemic.” �

FROM THE “DON’T TRY THIS ATHOME” DEPARTMENT...

The Arizona (U.S.)Highway Patrol came upona pile of smoldering metalimbedded into the side ofa cliff rising above theroad, at the apex of acurve.

The wreckage resembled the site of an air-plane crash, but it was a car. The type of car wasunidentifiable at the scene.

The boys in the lab finally figured out whatit was, and what had happened.

It seems that a guy had somehow got hold ofa JATO unit, (Jet Assisted Take Off, actually asolid-fuel rocket) that is used to give heavy mili-tary transport planes an extra ‘push’ for taking offfrom short airfields. He had driven his ChevyImpala out into the desert, and found a long,straight stretch of road. Then he attached theJATO unit to his car, jumped in, got up somespeed, and fired off the JATO!!

Best as they could determine, he was doingsomewhere between 250 and 300 mph (350-420kph) when he came to that curve....

The brakes were completely burned away,apparently from trying to slow the car.

NOTE: Solid-fuel rockets don’t have an‘off’... once started, they bum at full thrust ‘till thefuel is all gone.

Sometimes you just can’t write enough regu-lations to protect people from themselves. �


Activities Editor

Page Layout

Articles

If interested, contactRoger Volgstadt at (408) 285-2540

operational insulation must be over-heating and fire.

Now we can express why andhow operational spacings, testing, andconstruction contributes to the safety of the prod-uct.

First, spacings and, alternatively, dielectricstrength testing, demonstrate that the operationalinsulation is not likely to fail.

Second, short-circuit testing demonstratesthat upon failure of operational insulation, unac-ceptable overheating and fire are not likely.

Third, the requirement for V-I insulatingmaterials for operational insulation (without anytesting) presumes a fire, but only of short dura-tion. (The heat source ignites the V-I material inproximity to the heat source; the V-I materialburns away from the heat source until the remain-ing material is too far from the source tocontinue ignition, and the fire extinguishes.)

ACKNOWLEDGEMENTS

Thanks to a colleague for suggesting thistopic.

Your comments on this article are welcome.Please address your comments to the ProductSafety Newsletter, Attention: Roger Volgstadt,c/o Tandem Computers Inc., 10300 N. TantauAvenue, LOC 55-53,Cupertino,California 95014-0708.

If you want to discuss this article with yourcolleagues as well as with the author and editor,e-mail your comments to emc-pstc@@ieee.org.

*****

Technically SpeakingContinued From page 6

VOLUNTEERS NEEDED

CORRECTIONOur apologies to EuroConsult Inc. for

the incorrect address and phone numberfollowing their “Machinery Safety, Interna-tional and Euorpean Requirements” articlein the March/April edition of PSN. Thecorrect address and phone number ofEuroConsult is as follows:

EuroConsult Inc.P.O. Box 243Manchester, MA 01944

Phone: 508-526-1687Fax: 508-526-7118


- Maryland- Florida- Los Angeles County- Cook County (Illinois/Chicago), for some

product categories- North Carolina- Rhode Island- Virginia

This was the list we received from UL. Asyou can see from the list, the areas San Franciscoand New York City are not mentioned. If there areother areas that pstc members know about, pleasepost them. We could keep a running list of areas.

Best regards,

Dave LorussoEMC Corporation171 South StreetHopkinton, MA 01748508-435-1000, x7518508-435-5067 (fax)[email protected](email)

COMPLIANCE ENGINEERINGWEB SITE

Through a month of struggle, I managed tohave TREG, EMC-PSTC and some other info on-line. I am adding more to it Take a look at

h t t p : / / 1 9 9 . 1 7 1 . 2 7 . 1 9 4 /compliance_engineering/defaulthtm or http://199.171.27.194 for ease.

Your comments and suggestions are MORETHAN WELCOME. Please be patient if youexperience problems. Thanks.

Tom BaoTimeplex

[The editor would like to extend a specialthanks to Tom Bao for his efforts in creating ahome page that includes archives of past productsafety discussions on the emc-pstc forum. ‘Netsurfers should check out the above httpaddressesto see what a creative and valuable resource Tomhas created. - Ed]

INSTRUCTIONS FORUSING E-MAIL

1. To Subscribe to the EMC- PSTC ProductSafety Forum, send an e-mail message to:

[email protected]

and place the following command in thebody ofthe message:

subscribe emc-pstc <your_email_address>

(Do not include the brackets < or> ).

2. To send a message to the EMC-PSTCdiscussion group, simply send an e-mail message to the following address:

[email protected]

All mail sent to this Internet address will beimmediately echoed to everyone on the EMC-PSTC list by an automated list server.

Internet, Continued From Page 7


We Are Looking forProduct

Safety Articles!

Please send to:Roger Volgstadt

Tandem ComputersMIS 55-53

10300 N. Tantau Ave.Cupertino, CA 95014

3. To get help about using the IEEE’s EMC-PSTC discussion group, send an e-mail messageto:

[email protected]

and place the following command in thebody of the message: help

Should you have any questions that are notanswered in the above file, you may address themto the following: [email protected]

INTERNET RESOURCE FORPRODUCT SAFETY COMPLIANCE

[The following announcement appeared inthe PSN’s March/April edition. However, be-cause of numerous errors, we are re-publishingit here. Our apologies for any inconveniencecaused. - Ed. ]

Are you interested in news about UL,CSA, and the other Nationally RecognizedTesting Laboratories? Do you need to stayabreast of the international product safetyscene including information about IEC, VDE,the TUVs, the CB Scheme, and the EuropeanCommunity? Updates, information and re-sources for these and other product safetyagencies can now be found on the Internet.

Using the “gopher” client, point yourgopher at:

gopher.enews.com/l1/maga-zines/ alphabetic/all/ipsn/

If you have a Web browser, point it at:

http://www.enews.com/magazines/ipsn/

Once there, you will be able to sampleInternational Product Safety News, includingthe current index and a selection of articles.You can also search and/or view the archivesfor articles of interest in back issues.

IPSN is the newsletter devoted to interna-tional product safety compliance. For subscrip-tions, contact:

Art Michael, EditorInt’l Product Safety NewsP.O.Box 1561-NREMiddletown, CT 06457-8061Phone (203)344-1651Fax (203)[email protected] n


Institutional Listings


We are grateful for the assistance given by these firms and invite application for Institutional Listingsfrom other firms interested in the product safety field. An Institutional Listing recognizes contributionsto support publication of the Product Safety Newsletter of the IEEE EMC Society Product Safety

Technical Committee. Please direct inquiries to:

Ervin Gomez at (408) 553-7684 (phone) or (408) 553-7694 (fax)


BULK RATEU.S. POSTAGE PAIDCUPERTINO, CAPERMIT NO. 138

c/o Tandem Computers Incorporated10300 North Tantau Avenue, Loc 55-53Cupertino, CA 95014Attn: Roger Volgstadt

TheProductSafetyNewsletter

ADDRESS CORRECTION REQUESTED

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