Re: Australian compliance to ARE: creepage v breakdown voltage
Yes, NATA has informed us that the RTA list is being updated soon. Curtis-Straus (USA) is also accredited to perform testing to AS/ACIF S043. Jon Curtis Kevin Richardson wrote: Kristiaan, Equipment which falls under TLN Category A50 is required to comply with ACA TS001:1997 (Compliance Level 3) and AS/ACIF S043 - Parts 1, 2 3 as appropriate (Compliance Level 3 from 1 Jan 02). You said deemed to comply but I presume you mean need to comply so this is correct. Compliance Level 3 does indeed require test reports be from an Recognised Testing Authority (RTA). Compliance Level 3 requirements are spelt out in the TLN Section 4.6(1) and 4.6(2). Yes there are other options to compliance with Compliance Level 3 instead of a test report from an RTA as listed in 4.6(2). NOTE: 4.6.(2)(c) I do not think could be applied as there is no reason a Category A50 device could not be tested in a lab. In addition, 4.6(2)(d), 4.6(2)(e), 4.6.(2)(f) and 4.6(2)(g) do not apply to Category A50 equipment. The only compliance options therefore for a Category A50 device would be: 1. a test report from an RTA; or 2. a written statement from a certification body. The NATA RTA listing is not up-to-date even though the last revision was dated 7 Mar 02. Apart from BABT TUV Product Services lab in Santa Clara, USA, there are at least 2 other labs that I am aware of accredited to S043: a) Austest (Sydney, Australia); and b) Comtest (Melb, Australia) Details for these labs can be found in the RTA listing on the NATA web site you referenced. Best regards, Kevin Richardson Stanimore Pty Limited Compliance Advice Solutions for Technology (including Australian Agent Services) (Legislation/Regulations/Standards) Ph: 02-4329-4070 (Int'l: +61-2-4329-4070) Fax: 02-4328-5639 (Int'l: +61-2-4328-5639) Mobile: 04-1224-1620 (Int'l: +61-4-1224-1620) Email:k...@compuserve.com (kevin.richard...@ieee.org - alternate email) The material transmitted in this message or contained in attachments to this message may contain confidential and/or privileged material and is intended only for the addressee. Any use of or reliance upon this material by persons or entities other than the addressee is prohibited. If you receive this in error, please notify the sender and destroy any copies of the material immediately. -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of kristiaan.carpent...@alcatel.be Sent: Saturday, 16 March 2002 3:12 AM To: Emc-Pstc Post Subject: Australian compliance to ARE: creepage v breakdown voltage Hello, According to the latest version of the Telecommunication Labelling Notice 2001, products in the Category A50 are deemed to comply with ACA TS-001-1997 and AS/ACIF S043-2001. No problem for TS-001, but S043 needs Compliance level 3 only since January 1rst 2002. The general approach is that testing for S043 must be done by a Recognised Testing Authority. After verifying the latest list of RTA´s http://www.nata.asn.au/downloads/rtalist.pdf of March 7th, only 1 lab seems to be listed as RTA and it is not even located in Australia, but in the US. From my reading of the Labelling Notice, Schedule 3 seems to give however other possibilities to comply, like a Certification or Competent body. Any-one can shed some light on this issue? Regards, Kris Carpentier -- Jon D. Curtis, P.E. Director of Engineering Curtis-Straus LLC NRTL TCB One Stop Laboratory for NEBS, EMC, Product Safety, and Telecom Testing. 527 Great Road Littleton, MA 01460 USA Voice 978-486-8880 Fax 978-486-8828 email: jcur...@curtis-straus.com WWW.CURTIS-STRAUS.COM
RE: creepage v breakdown voltage
I have not been following this topic closely but some contributors have missed the point that PRIMARY Circuits are subject to high voltage transients and SECONDARY circuits are subject only to continuous stress. This is why 8mm Reinforced is reasonable (and necessary) in a primary circuit whereas only a couple of mm's may be all that is required in a secondary circuit. Insulation has a limited life - life testing on high voltage pulse transformers will show that - and whereas constant stress will (eventually) cause breakdown transients will also. This is analogous to the relationship of Failure Rate to constant stress and also to Switching Stress. (Note that light bulbs will give much longer life with not switched but left on permanently. ALSO - if a high (transient) voltage causes an electrical breakdown it is quite likely that local ionization will occur and permit the arc to be maintained by a much lower voltage (like the normal applied mains voltage). Hence Primary insulation Secondary Insulation. Best regards Gregg PLEASE NOTE: We are currently experiencing serious problems with our service provider PLEASE reply only to gr...@test4safety.com and ignore any reference to pgtv.net, Thank you. Basically, I start with 1Mv/meter STP and work down from there. Therefore, 1mm means 1Kv. Now, throw in a x2 safety factor and you get 2mm spacing. Now increase to 1.5Kv and you end up with 2.5mm? Well, okay. Surface contamination sets in over time? Well, okay again. Obviously, I've been doing some extreme fudging, but it ends up darn close most of the time. list
RE: creepage v breakdown voltage
Time certainly couldn't account for wide ranging humidity or altitude, but perhaps lessor humidity and air pressure changes. The time may have more to do with settling capacitive effects first. Stephen At 10:38 AM 3/15/2002, MCA Compliance wrote: These factors are certainly all relevant, but I was under the impression (maybe incorrectly so?) that the requirement to apply the test voltage for 60 seconds during the type test was to account for all these degradating factors. Brian -Original Message- From: Stephen Phillips [mailto:step...@cisco.com] Sent: 15 March 2002 15:17 To: Roman, Dan Cc: 'MCA Compliance'; Emc-Pstc Post Subject: RE: creepage v breakdown voltage Try this. For flat electrodes, at sea level, and normal temperatures; eliminating such factors as humidity, dust, illumination, and the electrode materials; the molecules of the gases that compose common air, get ionized in the presence of an electric field of about 30KV/cm. So, since - electrode shape, barometric pressure, temperature, humidity, dust, presence of photons, and composition of the materials and shape of the electrodes, as well as the composition of the 'air' (gases), and also any other local (competing) electromagnetic fields - can all affect the definitive voltage that will jump a given gap - is it any wonder that the standard includes what otherwise appears to be a lot of slop. Stephen At 09:28 AM 3/15/2002, Roman, Dan wrote: I was looking into this a few weeks ago also and found similar results experimentally as other posters have mentioned. The only voltage per inch spec I was able to come up with was in the IPC specs but they were way out of whack! 0.12 mils per volt or more meaning that 2121 Vdc distance that the safety standards say should be 2.5 mm the IPC spec is saying you need 5 mm While the safety standards may be conservative to allow for temperature, grease, dirt, etc. over time the IPC specs are ultra-conservative. The dielectric tables for hermetically sealed material group III is probably closer to the actual breakdown but I never did find a spec I could use to predict the ACTUAL breakdown voltage of a gap between traces. If anyone finds a rule of thumb or equation I'd like to have it also. Dan -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 4:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: creepage v breakdown voltage
Regarding Paschen's Law: http://home.earthlink.net/~jimlux/hv/hvmain.htm http://home.earthlink.net/~jimlux/hv/paschen.htm Stephen At 12:51 PM 3/15/2002, Doug McKean wrote: I've done my own testing and researched the thing as well. I think we've had some serious discussions here about this subject in the past. If the archives are available, it would be beneficial to go through them. Also, get a little hipot tester from any of the hipot mfrs for your own bench testing. That's highly educational as well as nipping problems in the bud. You'll first have to jump into Paschen's Law and all that involves with pressure/humidity/geometry of the probe tips used, etc ... Basically, I start with 1Mv/meter STP and work down from there. Therefore, 1mm means 1Kv. Now, throw in a x2 safety factor and you get 2mm spacing. Now increase to 1.5Kv and you end up with 2.5mm? Well, okay. Surface contamination sets in over time? Well, okay again. Obviously, I've been doing some extreme fudging, but it ends up darn close most of the time. Follow the standards when in any doubt. I'm not really sure, but I was told many years ago that wire mfrs use as much as a x7 safety factor for their insulation or used to. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: creepage v breakdown voltage
I've done my own testing and researched the thing as well. I think we've had some serious discussions here about this subject in the past. If the archives are available, it would be beneficial to go through them. Also, get a little hipot tester from any of the hipot mfrs for your own bench testing. That's highly educational as well as nipping problems in the bud. You'll first have to jump into Paschen's Law and all that involves with pressure/humidity/geometry of the probe tips used, etc ... Basically, I start with 1Mv/meter STP and work down from there. Therefore, 1mm means 1Kv. Now, throw in a x2 safety factor and you get 2mm spacing. Now increase to 1.5Kv and you end up with 2.5mm? Well, okay. Surface contamination sets in over time? Well, okay again. Obviously, I've been doing some extreme fudging, but it ends up darn close most of the time. Follow the standards when in any doubt. I'm not really sure, but I was told many years ago that wire mfrs use as much as a x7 safety factor for their insulation or used to. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: creepage v breakdown voltage
I read in !emc-pstc that MCA Compliance bally...@iolfree.ie wrote (in nbbblhpagldfkfbcdencaemojjac.bally...@iolfree.ie) about 'creepage v breakdown voltage', on Fri, 15 Mar 2002: How did they arrive at 2.5 mm ??? IEC TC74, responsible for IEC60950, didn't arrive at it. There is a special committee, TC28, that deals with clearance and creepage. You may find, from the public part of the IEC web site, that there is an Irish person on TC28 who can help you. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Australian compliance to ARE: creepage v breakdown voltage
Hello, According to the latest version of the Telecommunication Labelling Notice 2001, products in the Category A50 are deemed to comply with ACA TS-001-1997 and AS/ACIF S043-2001. No problem for TS-001, but S043 needs Compliance level 3 only since January 1rst 2002. The general approach is that testing for S043 must be done by a Recognised Testing Authority. After verifying the latest list of RTA´s http://www.nata.asn.au/downloads/rtalist.pdf of March 7th, only 1 lab seems to be listed as RTA and it is not even located in Australia, but in the US. From my reading of the Labelling Notice, Schedule 3 seems to give however other possibilities to comply, like a Certification or Competent body. Any-one can shed some light on this issue? Regards, Kris Carpentier
RE: creepage v breakdown voltage
Remember that some of that distance, I believe, accounts for when the boards get dirty, and the pollutants build up and reduce the spacings. When you test the boards during the evaluation they are almost always clean with no pollution build-up. Gary -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 4:39 AM To: Emc-Pstc Post Subject: RE: creepage v breakdown voltage Peter I agreee with your comment, but, I have seen lots of boards (material group III) pass high pot tests at 1.5kV with only 2 mm creepage on the boards. yet, 950 specifies 2.5mm for basic insulation. This is why I am after some independent experimental test data correlating creepage and dielectric strength, with different board material properties taken into account. I suppose to flip it around, if a board passes the hi-pot for 1 minute with 2 mm creepage (and the fact that it passes the hi-pot, means the clearance must also have been adequate?), why does 60950 look for 2.5mm creepage ??? rgds Brian -Original Message- From: Peter Merguerian [mailto:pmerguer...@itl.co.il] Sent: 15 March 2002 12:00 To: 'MCA Compliance'; Emc-Pstc Post Subject: RE: creepage v breakdown voltage Brian, Your PCB manufacturer should be able to tell you what spacings to keep in order to withstand the test voltages. It all depends on the base material used for the PCB which all have different dielectric strength properties. Remember, the standards reference a minimum creepage distance AND you must still pass the electric strength tests. This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il http://www.i-spec.com -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 11:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: creepage v breakdown voltage
Try this. For flat electrodes, at sea level, and normal temperatures; eliminating such factors as humidity, dust, illumination, and the electrode materials; the molecules of the gases that compose common air, get ionized in the presence of an electric field of about 30KV/cm. So, since - electrode shape, barometric pressure, temperature, humidity, dust, presence of photons, and composition of the materials and shape of the electrodes, as well as the composition of the 'air' (gases), and also any other local (competing) electromagnetic fields - can all affect the definitive voltage that will jump a given gap - is it any wonder that the standard includes what otherwise appears to be a lot of slop. Stephen At 09:28 AM 3/15/2002, Roman, Dan wrote: I was looking into this a few weeks ago also and found similar results experimentally as other posters have mentioned. The only voltage per inch spec I was able to come up with was in the IPC specs but they were way out of whack! 0.12 mils per volt or more meaning that 2121 Vdc distance that the safety standards say should be 2.5 mm the IPC spec is saying you need 5 mm While the safety standards may be conservative to allow for temperature, grease, dirt, etc. over time the IPC specs are ultra-conservative. The dielectric tables for hermetically sealed material group III is probably closer to the actual breakdown but I never did find a spec I could use to predict the ACTUAL breakdown voltage of a gap between traces. If anyone finds a rule of thumb or equation I'd like to have it also. Dan -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 4:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: creepage v breakdown voltage
Doing high voltage power supplies we found we always got in trouble using 20,000 V/in and things worked well when we kept below 10,000 V/in. Metric that's 790 V/mm and 390 V/mm This was free air and not some kind of pointy structure. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Roman, Dan dan.ro...@intel.com To: 'MCA Compliance' bally...@iolfree.ie; Emc-Pstc Post emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Friday, March 15, 2002 6:49 AM Subject: RE: creepage v breakdown voltage I was looking into this a few weeks ago also and found similar results experimentally as other posters have mentioned. The only voltage per inch spec I was able to come up with was in the IPC specs but they were way out of whack! 0.12 mils per volt or more meaning that 2121 Vdc distance that the safety standards say should be 2.5 mm the IPC spec is saying you need 5 mm While the safety standards may be conservative to allow for temperature, grease, dirt, etc. over time the IPC specs are ultra-conservative. The dielectric tables for hermetically sealed material group III is probably closer to the actual breakdown but I never did find a spec I could use to predict the ACTUAL breakdown voltage of a gap between traces. If anyone finds a rule of thumb or equation I'd like to have it also. Dan -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 4:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: creepage v breakdown voltage
*snippped from Stephen Phillips email** The geometry of the surface across which the potential is laid matters too (curves, points, parallel planes), doesn't it. Again, maybe the committee just added guaranteed slop. * Yes, definitely. The Electric field gradients increase dramatically around sharp metal points. (if you were graphing the electric field, the equipotentials get closer). The breakdown distance between two pointy electrodes is much less than the breakdown distance between two round balls. A great reference for intuitively sketching field lines around conductors can be found on pages 53-55 of Fields and Waves in Communication Electronics, second edition by Ramo, Whinnery and Van Duzer. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | -Original Message- From: Stephen Phillips [SMTP:step...@cisco.com] Sent: Friday, March 15, 2002 7:50 AM To: MCA Compliance Cc: Emc-Pstc Post Subject: RE: creepage v breakdown voltage Humidity matters. Some years back, when doing some experiments around this subject - I too was surprised at just how much voltage different gaps could bear, such that the standard seemed gross overkill. But in a less than purely scientific way, I decided to breath (just breath, not blow) in the vicinity of the withstand, and got different results. It was winter (dry air), and my merely breathing normally - within about a foot of the gap under test - caused a 400V(DC) lower breakdown. I know the standard doesn't hold us to tight humidity spec's, only pollution degree, but maybe the committee that came up with this added enough margin to be sure to always cover such issues. The geometry of the surface across which the potential is laid matters too (curves, points, parallel planes), doesn't it. Again, maybe the committee just added guaranteed slop. There is no such thing as too safe. Stephen At 07:39 AM 3/15/2002, MCA Compliance wrote: Peter I agreee with your comment, but, I have seen lots of boards (material group III) pass high pot tests at 1.5kV with only 2 mm creepage on the boards. yet, 950 specifies 2.5mm for basic insulation. This is why I am after some independent experimental test data correlating creepage and dielectric strength, with different board material properties taken into account. I suppose to flip it around, if a board passes the hi-pot for 1 minute with 2 mm creepage (and the fact that it passes the hi-pot, means the clearance must also have been adequate?), why does 60950 look for 2.5mm creepage ??? rgds Brian -Original Message- From: Peter Merguerian [mailto:pmerguer...@itl.co.il] Sent: 15 March 2002 12:00 To: 'MCA Compliance'; Emc-Pstc Post Subject: RE: creepage v breakdown voltage Brian, Your PCB manufacturer should be able to tell you what spacings to keep in order to withstand the test voltages. It all depends on the base material used for the PCB which all have different dielectric strength properties. Remember, the standards reference a minimum creepage distance AND you must still pass the electric strength tests. This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il/ http://www.i-spec.com/ -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 11:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation
Re: creepage v breakdown voltage
Hi All, The Creepage and clearance specifications take into account the long term degradation of spacings due to environmental conditions. Just because it will pass the test today when it is clean and pure does not mean that this condition will last forever. Scott MCA Compliance wrote: Peter I agreee with your comment, but, I have seen lots of boards (material group III) pass high pot tests at 1.5kV with only 2 mm creepage on the boards. yet, 950 specifies 2.5mm for basic insulation. This is why I am after some independent experimental test data correlating creepage and dielectric strength, with different board material properties taken into account. I suppose to flip it around, if a board passes the hi-pot for 1 minute with 2 mm creepage (and the fact that it passes the hi-pot, means the clearance must also have been adequate?), why does 60950 look for 2.5mm creepage ??? rgds Brian -Original Message- From: Peter Merguerian [mailto:pmerguer...@itl.co.il] Sent: 15 March 2002 12:00 To: 'MCA Compliance'; Emc-Pstc Post Subject: RE: creepage v breakdown voltage Brian, Your PCB manufacturer should be able to tell you what spacings to keep in order to withstand the test voltages. It all depends on the base material used for the PCB which all have different dielectric strength properties. Remember, the standards reference a minimum creepage distance AND you must still pass the electric strength tests. This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il http://www.i-spec.com -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 11:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: creepage v breakdown voltage
I was looking into this a few weeks ago also and found similar results experimentally as other posters have mentioned. The only voltage per inch spec I was able to come up with was in the IPC specs but they were way out of whack! 0.12 mils per volt or more meaning that 2121 Vdc distance that the safety standards say should be 2.5 mm the IPC spec is saying you need 5 mm While the safety standards may be conservative to allow for temperature, grease, dirt, etc. over time the IPC specs are ultra-conservative. The dielectric tables for hermetically sealed material group III is probably closer to the actual breakdown but I never did find a spec I could use to predict the ACTUAL breakdown voltage of a gap between traces. If anyone finds a rule of thumb or equation I'd like to have it also. Dan -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 4:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: creepage v breakdown voltage
Humidity matters. Some years back, when doing some experiments around this subject - I too was surprised at just how much voltage different gaps could bear, such that the standard seemed gross overkill. But in a less than purely scientific way, I decided to breath (just breath, not blow) in the vicinity of the withstand, and got different results. It was winter (dry air), and my merely breathing normally - within about a foot of the gap under test - caused a 400V(DC) lower breakdown. I know the standard doesn't hold us to tight humidity spec's, only pollution degree, but maybe the committee that came up with this added enough margin to be sure to always cover such issues. The geometry of the surface across which the potential is laid matters too (curves, points, parallel planes), doesn't it. Again, maybe the committee just added guaranteed slop. There is no such thing as too safe. Stephen At 07:39 AM 3/15/2002, MCA Compliance wrote: Peter I agreee with your comment, but, I have seen lots of boards (material group III) pass high pot tests at 1.5kV with only 2 mm creepage on the boards. yet, 950 specifies 2.5mm for basic insulation. This is why I am after some independent experimental test data correlating creepage and dielectric strength, with different board material properties taken into account. I suppose to flip it around, if a board passes the hi-pot for 1 minute with 2 mm creepage (and the fact that it passes the hi-pot, means the clearance must also have been adequate?), why does 60950 look for 2.5mm creepage ??? rgds Brian -Original Message- From: Peter Merguerian [mailto:pmerguer...@itl.co.il] Sent: 15 March 2002 12:00 To: 'MCA Compliance'; Emc-Pstc Post Subject: RE: creepage v breakdown voltage Brian, Your PCB manufacturer should be able to tell you what spacings to keep in order to withstand the test voltages. It all depends on the base material used for the PCB which all have different dielectric strength properties. Remember, the standards reference a minimum creepage distance AND you must still pass the electric strength tests. This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il http://www.i-spec.com -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 11:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: creepage v breakdown voltage
Peter I agreee with your comment, but, I have seen lots of boards (material group III) pass high pot tests at 1.5kV with only 2 mm creepage on the boards. yet, 950 specifies 2.5mm for basic insulation. This is why I am after some independent experimental test data correlating creepage and dielectric strength, with different board material properties taken into account. I suppose to flip it around, if a board passes the hi-pot for 1 minute with 2 mm creepage (and the fact that it passes the hi-pot, means the clearance must also have been adequate?), why does 60950 look for 2.5mm creepage ??? rgds Brian -Original Message- From: Peter Merguerian [mailto:pmerguer...@itl.co.il] Sent: 15 March 2002 12:00 To: 'MCA Compliance'; Emc-Pstc Post Subject: RE: creepage v breakdown voltage Brian, Your PCB manufacturer should be able to tell you what spacings to keep in order to withstand the test voltages. It all depends on the base material used for the PCB which all have different dielectric strength properties. Remember, the standards reference a minimum creepage distance AND you must still pass the electric strength tests. This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il http://www.i-spec.com -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 11:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: creepage v breakdown voltage
Brian, Your PCB manufacturer should be able to tell you what spacings to keep in order to withstand the test voltages. It all depends on the base material used for the PCB which all have different dielectric strength properties. Remember, the standards reference a minimum creepage distance AND you must still pass the electric strength tests. This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il http://www.i-spec.com -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 11:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
creepage v breakdown voltage
does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
