Re: Varistor to Ground
I read in !emc-pstc that Chris Maxwell chris.maxw...@nettest.com wrote (in 83d652574e7af740873674f9fc12dbaaf7e...@utexh1w2.gnnettest.com) about 'Varistor to Ground', on Mon, 22 Apr 2002: I read your quote below regarding the safety implications of placing MOVs between AC power and ground: Some ban it already: others will in due course, AFAIK. What about sidactors? (essentially a specialized Silicon Controlled Rectifier). We have used them on Telecom circuits with good success with hipot and surge testing. They are more reliable than MOV's as they don't degrade with every activation. Are sidactors banned? Will they be banned? If not, they are an excellent alternative to MOVs. I know of two manufacturers: Teccor and Raychem. Small quantities of the Raychem parts are available from Digi-Key (www.digikey.com). Very hot news! I have just returned from an IEC TC108 MT1 meeting where this subject was discussed, and I asked about devices other than MOVs. It was said that these devices are only just beginning to be discussed by IEC SC37A, but I have no more details at present. -- 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...@attbi.com 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: Varistor to Ground
Hi John, I read your quote below regarding the safety implications of placing MOVs between AC power and ground: Some ban it already: others will in due course, AFAIK. What about sidactors? (essentially a specialized Silicon Controlled Rectifier). We have used them on Telecom circuits with good success with hipot and surge testing. They are more reliable than MOV's as they don't degrade with every activation. Are sidactors banned? Will they be banned? If not, they are an excellent alternative to MOVs. I know of two manufacturers: Teccor and Raychem. Small quantities of the Raychem parts are available from Digi-Key (www.digikey.com). 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: John Woodgate [SMTP:j...@jmwa.demon.co.uk] Sent: Friday, April 19, 2002 4:31 PM To: emc-p...@majordomo.ieee.org Subject: Re: Varistor to Ground I read in !emc-pstc that Dan Kwok dk...@intetron.com wrote (in 3cc06a29.e6198...@intetron.com) about 'Varistor to Ground', on Fri, 19 Apr 2002: Is it generally permissible to put a varistor (MOV) across the 120 Vac line and ground for surge suppression/line conditioning products? I can see some potential safety implications here if the MOV shorts but I am interested in how this is addressed in the relevant safety standards. Some ban it already: others will in due course, AFAIK. -- 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...@attbi.com 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...@attbi.com 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: Varistor to Ground
I read in !emc-pstc that Dan Kwok dk...@intetron.com wrote (in 3cc06a29.e6198...@intetron.com) about 'Varistor to Ground', on Fri, 19 Apr 2002: Is it generally permissible to put a varistor (MOV) across the 120 Vac line and ground for surge suppression/line conditioning products? I can see some potential safety implications here if the MOV shorts but I am interested in how this is addressed in the relevant safety standards. Some ban it already: others will in due course, AFAIK. -- 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...@attbi.com 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: Varistor to Ground
Dan, A good place to start would be CENELC's List of Decisions regarding EN60950 3rd Ed. (see attached). Pay particular attention to page 3. (See attached file: EN60950_3rd,CCA.pdf) Best regards, Ron Pickard rpick...@hypercom.com dk...@intetron.com Sent by: To: emc-p...@majordomo.ieee.org owner-emc-pstc@majordomcc: o.ieee.org Subject: Varistor to Ground 04/19/02 12:04 PM Please respond to dkwok Hi all, Is it generally permissible to put a varistor (MOV) across the 120 Vac line and ground for surge suppression/line conditioning products? I can see some potential safety implications here if the MOV shorts but I am interested in how this is addressed in the relevant safety standards. Dan Kwok Principal Engineer http://www.intetron.com --- 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...@attbi.com 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 EN60950_3rd,CCA.pdf Description: Adobe PDF document
