RE: Interpretation of IEC 1000-4-4
Hi Geoffrey, You pose a good question with regard to EFT testing. We have been over this one in the past, and after consulting with several experts, we have come up with the following: Although many commercial test labs recommend that you test all possible line coupling combinations (for a total of 7 if you are dealing with singe phase.), We have detirmined that Common mode testing is all that really needs to be accomplished. The thoughts behind this are that due to the rise times involved with the pulses, capacitive coupling within the power cable and power supply converts the differencial bursts to common mode anyway. We do however, test the lines indivdually as well, for the simple reason of satisfying the demands of our customers. What we end up testing is 4 combinations; L1, L2, GND, and Common mode(all three). I would be interested to hear other's thoughts on this subject... Regards, Randy Flinders EMC Test Engineer Emulex Network Systems r_flind...@emulex.com * Opinions expressed are personal and in no way represent the position of Emulex Corporation. -- From: Geoffrey Skanes[SMTP:ems...@nortel.ca] Sent: Thursday, July 31, 1997 12:53 PM To: emc-pstc Subject: Interpretation of IEC 1000-4-4 Hi: I've recently had a need to re-visit the application of EFT pulses on AC power cords. Although the current version of the std. (1st ed.,1995) discusses assymetric application of the EFT pulse (Section 6.2), the std does not explicitly describe that the pulse application must be done on one conductor at a time. Considering Figures 4 and 11, it would appear that pulses can be applied to the protective earth (ground). Question is, is simultaneous application of the burst (in common mode) a valid and necessary test case? I believe the answer is yes for the following reasons: - I/O lines are exposed to EFT via the capacitive coupling clamp in true common mode, so why would power cords be treated differently? - for the same reasons that I/O cables are exposed to common mode burst events in reality, power cords should be exposed to common mode events. - A number of commercial stds, i.e. ETS 300-342-2, describe common mode application of the burst. Anyone else with comments on this? Regards, Geoff Skanes EMC Engineer Nortel Technology RTP, NC
Re: Korea in a Nut Shell
Haitong EMC Inc. Tel : 82-339-376-4117 Fax : 82-339-376-4118 Email : hait...@soback.kornet.nm.kr Ryan Kim / President of Haitong EMC Inc. -- $)C > :83= ;g6w: eric.lif...@natinst.com > 9^4B ;g6w: emc-p...@majordomo.ieee.org > A&8q: Korea in a Nut Shell > 3/B%: 19973b 7?y 31@O 8q?d@O ?@@| 5:52 > > What a surprise! Where did you get those wrong information on Korea EMI regulation. I wish you have confidence before post your opinion. > > A past posting requested info about Korea EMC Requirements. Here's what > I've learned, condensed for your reading pleasure, and interpretted for > it's deeper meaning. > > A foreign company must hire a Korean EMC lab to represent them for > government certification, and pay the lab accordingly for the emission > tests, report creation, and submission of the whole thing to the Korean > authorities - along with the required fee. User manuals must be translated > into Hangul/Korean. You might also have to provide full schematic diagrams > with the test report. > ** What did you mean hire Korean EMC lab. For the Korea EMI, only Korea government authorized lab can issue the report to apply for the final certi from the government. Mostly in Korea (31 labs) and 4 in United States (IBM). Why don't you apply for the Korea EMI lab accredition instead of hiring Korea lab! There is no law that other contries lab can not apply for the accredition. 4 IBM labs approve the fact. Normal charge for the test and report is U$600 per model which is almost one third of America lab charges. Submission fee to the government is U$70 which is more than 1/10 of FCC application fee. Korea EMI lab issue the report and get test and report fee as well as application from the applicant and submmit test report to the government with submission fee without extra charge. What is wrong with that? Also, EMI lab get the certi and delivery to the applicant. Certi is issued within 3 days after the submission which is really short period of time compared to the other countries. User's manual must be translated in to Korean because Korea government wants to let Korean people have the Korean written manual for the purchasing imported devices. If you do not translate your manual and supply with English manual, how Korean people read your manual and understand how operate? We, Korean people have learn English to use your products? This is the reason why Korean government want to see Korean written manual and let foreign manufacturers supply their system with Korean written manual. I don't see any problem with that. If Korea manufacturer supply its system with Korean written user's manual, how American customer will act? Imagine! Full circuit diagram must be provided? Where did you get this wrong information? Only one page block diagran is needed. If you even do not want to provide one page block diagram, its O.K. Korea EMI lab draw the block diagram for you. > This must be repeated every year, and for each product. Every year, every > product (plus fees!). > ** NO! If your system is no more manufactured after one year, just forget it. If your system is keeping imported after the one year, you are subjected to have test report to check the your system's EMI condition to compare to the origition condition when you get the EMI certi. Thus, if you want have the report, apply to the Korea EMI lab and get the test report. We charge U$600 for the test and report which is same as first test and report. If we do not have this kind of survellience system, how Korea government control the inspection. Just get the Certi with good system and sell bad system to the public without and limit? And except test and report fee, no other charge and submission fee is needed. If your system is so good and very popular to the public in Korea, and keep selling for more than year with one model, get just one more report after one year. I bet your system would not be popular and would be closed within one year, then just forget about retest. > Now stop a minute and consider the impact to an imaginary company that > markets a relatively common but noticable number of products. Let's toss > up the number 60 for products, and assume a work week in Korea is five days > long, and that we're using a typical lab with a typical open area test > site... ** What company have the number 60 for products? Let me know. Each model, let say one company have 5 computers with different model name and spec. If this company export 3 models to the Korea, only 3 computers are subject to get EMI certi. Now, let's assume that you use my open site. > Each emission test takes two days to run, plus time to write and assemble > the test report, maybe three days total. (Labs tend to b
Re: Korea in a Nut Shell (From the Nut Shell)
Haitong EMC Inc. Tel : 82-339-376-4117 Fax : 82-339-376-4118 Email : hait...@soback.kornet.nm.kr Ryan Kim / President of Haitong EMC Inc. -- $)C > :83= ;g6w: Ryan Kim > 9^4B ;g6w: eric.lif...@natinst.com; emc-p...@majordomo.ieee.org > A&8q: Re: Korea in a Nut Shell > 3/B%: 19973b 8?y 1@O 1]?d@O ?@HD 3:45 > > Haitong EMC Inc. > Tel : 82-339-376-4117 > Fax : 82-339-376-4118 > Email : hait...@soback.kornet.nm.kr > Ryan Kim / President of Haitong EMC Inc. > > -- > > :83= ;g6w: eric.lif...@natinst.com > > 9^4B ;g6w: emc-p...@majordomo.ieee.org > > A&8q: Korea in a Nut Shell > > 3/B%: 19973b 7?y 31@O 8q?d@O ?@@| 5:52 > > > > > What a surprise! > > Where did you get those wrong information on Korea > EMI regulation. I wish you have confidence before > post your opinion. > > I made comment right after you message. Please refer to the following. > > > -- Your original message > > A past posting requested info about Korea EMC Requirements. Here's what > > I've learned, condensed for your reading pleasure, and interpretted for > > it's deeper meaning. > > > > A foreign company must hire a Korean EMC lab to represent them for > > government certification, and pay the lab accordingly for the emission > > tests, report creation, and submission of the whole thing to the Korean > > authorities - along with the required fee. User manuals must be > translated > > into Hangul/Korean. You might also have to provide full schematic > diagrams > > with the test report. > > > ** What did you mean hire Korean EMC lab. For the Korea >EMI, only Korea government authorized lab can issue the >report to apply for the final certi from the government. >Mostly in Korea (31 labs) and 4 in United States (IBM). >Why don't you apply for the Korea EMI lab accredition >instead of hiring Korea lab! There is no law that other >contries lab can not apply for the accredition. 4 IBM labs >approve the fact. Normal charge for the test and report >is U$600 per model which is almost one third of America >lab charges. Submission fee to the government is U$70 >which is more than 1/10 of FCC application fee. Korea >EMI lab issue the report and get test and report fee as >well as application from the applicant and submmit test >report to the government with submission fee without >extra charge. What is wrong with that? Also, EMI lab >get the certi and delivery to the applicant. Certi >is issued within 3 days after the submission which is >really short period of time compared to the other countries. > >User's manual must be translated in to Korean because >Korea government wants to let Korean people have the >Korean written manual for the purchasing imported devices. >If you do not translate your manual and supply with English >manual, how Korean people read your manual and understand >how operate? We, Korean people have learn English to use >your products? This is the reason why Korean government >want to see Korean written manual and let foreign manufacturers >supply their system with Korean written manual. I don't see >any problem with that. If Korea manufacturer supply its system >with Korean written user's manual, how American customer will >act? Imagine! > >Full circuit diagram must be provided? Where did you get this >wrong information? Only one page block diagran is needed. >If you even do not want to provide one page block diagram, its >O.K. Korea EMI lab draw the block diagram for you. > > > > This must be repeated every year, and for each product. Every year, > every > > product (plus fees!). > > >** NO! If your system is no more manufactured after one year, just > forget it. If your system is keeping imported after the one year, > you are subjected to have test report to check the your system's > EMI condition to compare to the origition condition when you get > the EMI certi. Thus, if you want have the report, apply to the > Korea EMI lab and get the test report. We charge U$600 for the > test and report which is same as first test and report. If we do > not have this kind of survellience system, how Korea government > control the inspection. Just get the Certi with good system and > sell bad system to the public without and limit? And except > test and report fee, no other charge and submission fee is needed. > If your system is so good and very popular to the public in Korea, > and keep selling for more than year with one model, get just one > more report after one year. I bet your system would not be popular > and would be closed within one year, then just forget about retest. > > > Now stop a minute and consider the impact to an imaginary company that > > markets a relatively common but noticabl
MIL-STD-461,462
Greetings. Does anyone know of an EMC test laboratory in Australia which has experience in testing to MIL-STD-461 and/or MIL-STD-462 (Emissions & Susceptibility tests)? Sincerely, Peter Poulos = Peter Poulos Hardware Development Engineer Foxboro-L&N (Australia) Ph: +61 7 3340 2118 E-mail: pet...@foxln.com.au
Re: Flammability of Plastics for ITE
Please see clause 4.4.4--3rd para, although for decorative parts can be applied to other small materials like overlays, tapes etc. Since you are powered by Limited Power source, I doubt that anyone will ever question the flammability of these materials. sg...@brother.com RCIC - http://www.rcic.com Regulatory Compliance Information Center
Re: Flammability of Plastics for ITE
Please see 4.4.4, 3rd para, it is applicable for materials that you have in question. Since powered by a Lmited Power Source, I doubt that anyone will ever question the flammability of these parts anyways. Thanks sg...@brother.com RCIC - http://www.rcic.com Regulatory Compliance Information Center
EFT testing of three phase industrial equip
The test setups I have seen for CE testing involve single phase equipments. Looking for thoughts on EFT tests of high current three-phase equipment. Do I need to run A-B, B-C, C-A, A-GND, B-GND, C-GND, ABC-GND, AB-GND, BC-GND, CA-GND? Are there other combinations which must be addressed? Who makes an EFT gen to handle 440 volts wye? jgs
Re: Korea in a Nut Shell
Mr. Kim, Thank you very much for what I can trust are the true facts on the Korea EMI Certification. I'm sorry I may have upset you, but the information I had came from several sources and it seemed to be reliable, some of it still is. It seems my main errors were: (a) to assume Korean labs took the same time and cost doing EMI tests as US labs, and that (b) US lab test data could never be accepted for Korean certification. I was also under the impression that the EMI certificate cost was US$712, then US$389 every year after. This must have been the lab testing fees plus the government fees, from what you say. However, you confirmed the most troublesome requirements - yearly retesting and translation of the user manuals. Another label isn't fun either. You see, our products are not like typical ITE that people toss out after a couple years - they continue for years and years and years. One extreme example is our QBus interface card that we still make, it is for a computer (Digital LSI-11) that was first designed in the 1970s! By the end of this year we will have well over 200 products subject to EMI testing for Korea, such as PCI boards, ISA boards, SBus boards, PCMCIA boards, stand alone data extenders and more. A video board is easy to setup and test, set the resolution to maximum and go. Our boards have a variety of I/O methods, analog, digital, timers, and a variety of proprietary and new industrial data busses. We make ISM equipment, mostly PC based, and the majority are Class A. I think the EMI regulation fits the fast paced ITE industry well, but has serious drawbacks for ISM products like ours. We've already done CE for all of our products, we spent over US$1,000,000 on this while also building our own new EMC lab. We don't release new products without CE testing. Some products are also subject to FCC as well. We're also doing the Australia C-Tick. Now Korea has EMI requirements, next Taiwan has EMI requirements, the CE Mark will add several more EMC tests soon So, you might imagine that I (and maybe a few others too?) am frustrated by all the new things we must do. How many certificates, declarations, and labels and marks will be enough? A nearby computer company has a large staff (about 12+?) for EMI testing of maybe 40 products per year, and many obsolete, as you suggest, every year. Here, it is me and my technician for about 100 new products per year, and sustaining many old products too. From my experience working elsewhere and dealing with other labs, we're doing a darn good job business-wise! However, I must admire your lab's ability to perform all emission tests and write the test report in a single day. This is good example for the rest of us to emulate, where possible. Do you use an open area site or a semi-anechoic chamber? We use an OATS (we lease from another lab) that is 90 minutes drive away, one way. If all goes well we can complete two radiated tests in one shift. We have a method that cuts our report writing time down to almost as good as yours for a full CE test; we'd still like to make it shorter. Yes, I am aware that the FCC does not have NVLAP setup for Korea. I'm afraid I don't have much influence on such matters, and I agree it is not a fair situation. I plan to submit for NVLAP soon, but I don't enjoy the idea. Let me restate your key points to be sure if I understand the situation now and correct my errors for everybody's benefit in the internet: (1) US labs can apply for laboratory certification to run the tests themselves. (Good! What is the cost to apply?) (2) Retesting is required yearly if the product is still on the market. (This is what I was saying.) (3) Block diagrams are OK. (Good! Though this conflicts with another generally reputable source.) (4) Korean labs charge about US$600 for an entire test and report, usually done in one day. (Amazing!) (5) Two US labs are approved for the EMI certification test at this time. (Not so good, but better than I believed.) (6) The Korean government EMI certificate costs US$70 and is ready in three days after submission. (Good!) (7) User manuals must be translated into Korean prior to certification. (Costly to us.) (8) A label with government division number, emission class, fiscal year, and lab ID is required. Comments are welcome. Best Regards, Eric Lifsey Compliance Engineer National Instruments USA hait...@soback.kornet.nm.kr on 08/01/97 01:45:42 AM To: Eric Lifsey/AUS/NIC, emc-p...@majordomo.ieee.org cc: Subject: Re: Korea in a Nut Shell Haitong EMC Inc. Tel : 82-339-376-4117 Fax : 82-339-376-4118 Email : hait...@soback.kornet.nm.kr Ryan Kim / President of Haitong EMC Inc. -- > ?? > > ???: Korea in a Nut Shell > ???: 1997 > > What a surprise! Where did you get those wrong information on Korea EMI regulation. I wish you have confidence before post your opinion. > > A past posting requested info about Ko
Re: Korea in a Nut Shell (From the Nut Shell)
Just a brief note on the comments from Ryan (please correct me if I am wrong). I was in Korea 3 weeks ago visiting the Radio Research Laboratory and was told that they are no longer accrediting labs outside Korea until they have MOAs/MRAs in place. Regards, Chris Allen Senior Approvals Engineer 3Com Europe Ltd. - Previous Message To: emc-pstc @ ieee.org cc: From: haitong @ soback.kornet.nm.kr @ UGATE List-Post: emc-pstc@listserv.ieee.org Date: Friday August 1, 1997 06:55 Subject: Re: Korea in a Nut Shell (From the Nut Shell) --- --- Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: quoted-printable Haitong EMC Inc. Tel : 82-339-376-4117 Fax : 82-339-376-4118 Email : hait...@soback.kornet.nm.kr Ryan Kim / President of Haitong EMC Inc. -- > ? > > ???: Re: Korea in a Nut Shell > ???: 1997 > > Haitong EMC Inc. > Tel : 82-339-376-4117 > Fax : 82-339-376-4118 > Email : hait...@soback.kornet.nm.kr > Ryan Kim / President of Haitong EMC Inc. > > -- > > ??=0A> > =0A> > ???: Korea in a= Nut Shell > > ???: 1997 > > > > > What a surprise! > > Where did you get those wrong information on Korea > EMI regulation. I wish you have confidence before > post your opinion. > > I made comment right after you message. Please refer to the following. > > > -- Your original message > > A past posting requested info about Korea EMC Requirements. Here's= what > > I've learned, condensed for your reading pleasure, and interpretted= for > > it's deeper meaning. > > > > A foreign company must hire a Korean EMC lab to represent them for > > government certification, and pay the lab accordingly for the emiss= ion > > tests, report creation, and submission of the whole thing to the Ko= rean > > authorities - along with the required fee. User manuals must be > translated > > into Hangul/Korean. You might also have to provide full schematic > diagrams > > with the test report. > > > ** What did you mean hire Korean EMC lab. For the Korea >EMI, only Korea government authorized lab can issue the >report to apply for the final certi from the government. >Mostly in Korea (31 labs) and 4 in United States (IBM). >Why don't you apply for the Korea EMI lab accredition >instead of hiring Korea lab! There is no law that other >contries lab can not apply for the accredition. 4 IBM labs >approve the fact. Normal charge for the test and report >is U$600 per model which is almost one third of America >lab charges. Submission fee to the government is U$70 >which is more than 1/10 of FCC application fee. Korea >EMI lab issue the report and get test and report fee as >well as application from the applicant and submmit test >report to the government with submission fee without >extra charge. What is wrong with that? Also, EMI lab >get the certi and delivery to the applicant. Certi >is issued within 3 days after the submission which is >really short period of time compared to the other countries. > >User's manual must be translated in to Korean because >Korea government wants to let Korean people have the >Korean written manual for the purchasing imported devices. >If you do not translate your manual and supply with English >manual, how Korean people read your manual and understand >how operate? We, Korean people have learn English to use >your products? This is the reason why Korean government >want to see Korean written manual and let foreign manufacturers >supply their system with Korean written manual. I don't see >any problem with that. If Korea manufacturer supply its system >with Korean written user's manual, how American customer will >act? Imagine! > >Full circuit diagram must be provided? Where did you get this >wrong information? Only one page block diagran is needed. >If you even do not want to provide one page block diagram, its >O.K. Korea EMI lab draw the block diagram for you. > > > > This must be repeated every year, and for each product. Every year= , > every > > product (plus fees!). > > >** NO! If your system is no more manufactured after one year, jus= t > forget it. If your system is keeping imported after the one ye= ar, > you are subjected to have test report to check the your system'= s > EMI condition to compare to the origition condition when you ge= t > the EMI certi. Thus, if you want have the report, apply to the= > Korea EMI lab and get the test report. We charge U$600
Korea EMC
Ryan, I read your response to the "Korea in a Nut Shell" message. Thank you for that. I have some questions and comments. 1. How does a US lab apply for and get accreditation from the Korean government for EMI testing? I would like my local test house to apply. 2. Your price of U$670 for test, report and certification application is half the cost of a test and report at my local test house. I do not have to apply to the FCC for Class A equipment. A one day (6-8 hours) test is done and it takes 10 days to get the report. Your cost and turn-around time are half what I get here. 3. Touche on the language issue. I am paying for 6 (now 7 with Korea) translations all the time. I don't like it but it is a cost of doing business. 4. If my product continues to be imported into Korea after one year, you say I need to have a test report to check the product's EMI condition as compared to the original and that I have to apply to the Korean lab to get the test report. Question - does the Korean lab just re-print the original report or do I have to send another sample of the product back for another test? How is the product checked against the original tested product? >From an e-mail on 8 April 1997 from you to Bharat Shah regarding labeling of >the product - - If I have five distributors importing the same products, you >said that each of them has to get certification by applying for "same product >verification". Does that mean that each distributor must apply for this? Who do they apply to? Is it possible for me to get the registration, label the products here at my factory and ship them to the five distributors with all getting the same label? Most of my products will be shipped with my name on the certification label. That label has all of the approvals needed on it, that is CSA, CSA/NRTL, TUV, CE Marking, FCC statements, etc. Can I just add the Korean label requirements to my existing certification label? I do not put dealer or distributor names on my certification label or anywhere else on my products in this case. I do, however, sometimes do some private labeling. A customer of mine will have us place their name on the front of the product, i.e. the marketing name of the product. My certification label with my name and all approvals is placed on the back of the product. How does this affect the questions in the paragraph above? In a third variation, some of my customers contract us to make products for them and their name is placed on the certification label as well as on the marketing labels. In this case, I get CSA, TUV, etc. certifications in their name with me as the manufacturing location for that customer. How does this affect the questions in the paragraph above? Finally, someone at our embassy in Korea provided me with a chart that lists the products that need to have EMI testing. My products are not on that chart. It was in Korean and he provided it to me with his translation of the product types. It is not official and I cannot refer to it or attribute it to him. The chart is from a book, page 385 and the title is "Items subject to EMI testing" that he obtained from RRL. The hard question, if my product is not on that chart and I classify my product as Information Technology Equipment, then do I still need to get EMI registration? The chart listed the following equipment as subject to EMI testing: Wired Telecom Terminals Private Branch Exchanges Modems Credit Card Reference Machines Teletex Keyphones Telex Facsimilie Machines Videotext Videophones Word Processors Copying Machines General Purpose Computers Minicomputers Business Computers Industrial Computers Personal Computers Plotters (x,y plotters and drafting machines) Printers Data Service Units (DSU) Multiplexers (MUX) Monitors Keyboards Motherboards for PC's Power supply for PC's Cards for monitors (from among input/output interfaces for PC's) End of list from chart. Many thanks for all of your efforts to keep us going in the right direction. It is frustrating to sit here so far away while trying to cope with new rules in a land with a language we cannot read, write or speak. My compliments to you for making the effort to learn our language. Regards, Scott Douglas Principal Compliance Engineer ECRM Incorporated Telephone: 1-508-851-0207 Facsimilie: 1-508-851-7016 e-mail: sdoug...@ecrm.com
Lightning and Power Cross Testing
I've been asked to test a network powered (-130 Vdc) product to GR-1089-CORE for lightning and power cross. Does anyone out there have any suggestions on how to do this testing while the product is powered? The problem is that if you apply 1000 V, 10/1000 uSec, 100 A to tip/ring while the product is powered, you will damage the power source. I've looked into using series inductance followed by an MOV and capacitor, but I'm not sure if all the energy is getting to the UUT. Another problem is that my tester applies a short to tip and ring prior to the application of the test voltage. The same problem doing power cross (600 Vac, 1 A, 1 Sec). Applying this kind of voltage to the power source will damage it. Is there a way for the UUT to remain line powered and provide protection to the power source? Has anyone had similar problems? Thank you very much for any suggestions. Jerry
Re: Lightning and Power Cross Testing
See remarks below. Jon D. Curtis, PE Curtis-Straus LLC j...@world.std.com One-Stop Laboratory for EMC, Product Safety and Telecom 527 Great Roadvoice (508) 486-8880 Littleton, MA 01460 fax (508) 486-8828 http://world.std.com/~csweb On Thu, 31 Jul 1997, Jerry Martin wrote: > I've been asked to test a network powered (-130 Vdc) product to > GR-1089-CORE for lightning and power cross. > > Does anyone out there have any suggestions on how to do this testing > while the product is powered? > > The problem is that if you apply 1000 V, 10/1000 uSec, 100 A to tip/ring > while the product is powered, you will damage the power source. I've > looked into using series inductance followed by an MOV and capacitor, but > I'm not sure if all the energy is getting to the UUT. Another problem is > that my tester applies a short to tip and ring prior to the application > of the test voltage. To protect the power supply add as much resistance as you can push the required amount of current through. Then add a 2-10mH inductor (you can buy commercial or cut up a line filter). Make the protection two pole with capacitors (5uF to ground ought to do) and non-linear with MOVs rated just over 130VDC. To keep the EUT running during the power supply shorting action use a large capactor in series with the generator. You'll need to use a fairly large one to avoid cliping the trailing edge of the short circuit current waveform. Without running calcs, I believe the ballpark is 1000uF for a 5-10% reduction in short circuit fall time. Hopefully, your generator is a little long so that you can shorten it down to 1000uS. > > The same problem doing power cross (600 Vac, 1 A, 1 Sec). Applying this > kind of voltage to the power source will damage it. Is there a way for > the UUT to remain line powered and provide protection to the power > source? Seems to me you could use something like the loop simulator from part 68. Protect the DC power source with 10 Henry inductors in series with each lead. Check this out by placing a capacitor (say 1000uF) across the power supply end of the inductors (sans power supply) and measure the voltage on the cap with a volt meter (it ought to be real low). Be cautious with this set up because inductors with less than 1500V dielectric withstand capabilities are likely to become "fire or fragmentation" hazards. With Surge and Overvoltage testing eye protection is not optional. > > Has anyone had similar problems? > > Thank you very much for any suggestions. > > Jerry >
