Re: Varistors to Ground
Dear John, Varistors to Ground (earth) is a very old fashioned way for designing equipment to withstand transient voltages. A better and more sophisticated way is to use some better engineering principles; for example larger clearances/creepages (approx 6 mm) and good design of the power supply input, especially around the input chokes. Nowadays, of the hundreds of products which we test for safety and emc, a varistor between line-to-ground or neutral-to-ground is almost never used. If you do employ a varistor to ground, not only is it a problem with some countries (mainly due to Leakage of Current over time), but a bigger headache is the conduct of your 100% Production Line Dielectric Voltage Withstand Test. Each unit which must be subjected to this routine test must first be opened, the varistor disconnected before conducting the Dielectric Voltage Withstand Test. I hope that this additional piece of information will help you all analyze the high cost of putting a varistor to ground, with or without a spark gap connected in series to it. Happy and Safe Holidays to All, All: A couple of weeks back I posted a message regarding a CENELEC Decision that impacted the use of varistors between mains conductors and ground. I have appreciated the resulting messages / dialogues, but I still am unclear about my initial questions: 1) Is this Decision only for pluggable equipment type A, or is the spark-gap / fuse requirement in effect for pluggable equipment type B as well? 2) Will Denmark, UK, and Sweden accept varistors to ground if the circuit contains a spark-gap and two fuses? If this Decision means DK, UK, SE will simply not accept varistors to ground, then a lot of small pluggable type A equipment intended for sale in DK, UK, SE will have to either: 1) discontinue using varistors, or 2) become pluggable equipment type B (which would be onerous, given the IEC 309 plugs I've seen). I appreciate your input. John Boucher jpbouc...@lucent.com Decision text: Varistors Transient suppressors between the mains and the protective earth cannot be accepted by the following countries: * pluggable equipment type A: Austria, Belgium, Denmark, Finland, Norway, Sweden, UK pluggable equipment type B: Belgium, Denmark, Norway, UK A combination of a varistor in series with a spark gap (gas tube,) complying with basic insulation, and with a fuse will be accepted for: a)pluggable equipment type B and permanently connected equipment: * by all countries b)pluggable equipment type A: * by all countries except Denmark, UK, and Sweden For pluggable equipment type A two fuses are required. (to ensure that even by non-polarized plugs a fuse is provided) Permanently connected equipment connected to protective earth: * accepted by all countries - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Varistors to ground
All: A couple of weeks back I posted a message regarding a CENELEC Decision that impacted the use of varistors between mains conductors and ground. I have appreciated the resulting messages / dialogues, but I still am unclear about my initial questions: 1) Is this Decision only for pluggable equipment type A, or is the spark-gap / fuse requirement in effect for pluggable equipment type B as well? 2) Will Denmark, UK, and Sweden accept varistors to ground if the circuit contains a spark-gap and two fuses? If this Decision means DK, UK, SE will simply not accept varistors to ground, then a lot of small pluggable type A equipment intended for sale in DK, UK, SE will have to either: 1) discontinue using varistors, or 2) become pluggable equipment type B (which would be onerous, given the IEC 309 plugs I've seen). I appreciate your input. John Boucher jpbouc...@lucent.com Decision text: Varistors Transient suppressors between the mains and the protective earth cannot be accepted by the following countries: * pluggable equipment type A: Austria, Belgium, Denmark, Finland, Norway, Sweden, UK pluggable equipment type B: Belgium, Denmark, Norway, UK A combination of a varistor in series with a spark gap (gas tube,) complying with basic insulation, and with a fuse will be accepted for: a) pluggable equipment type B and permanently connected equipment: * by all countries b) pluggable equipment type A: * by all countries except Denmark, UK, and Sweden For pluggable equipment type A two fuses are required. (to ensure that even by non-polarized plugs a fuse is provided) Permanently connected equipment connected to protective earth: * accepted by all countries - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Varistors to Ground
All: A couple of weeks back I posted a message regarding a CENELEC Decision that impacted the use of varistors between mains conductors and ground. I have appreciated the resulting messages / dialogues, but I still am unclear about my initial questions: 1) Is this Decision only for pluggable equipment type A, or is the spark-gap / fuse requirement in effect for pluggable equipment type B as well? 2) Will Denmark, UK, and Sweden accept varistors to ground if the circuit contains a spark-gap and two fuses? If this Decision means DK, UK, SE will simply not accept varistors to ground, then a lot of small pluggable type A equipment intended for sale in DK, UK, SE will have to either: 1) discontinue using varistors, or 2) become pluggable equipment type B (which would be onerous, given the IEC 309 plugs I've seen). I appreciate your input. John Boucher jpbouc...@lucent.com Decision text: Varistors Transient suppressors between the mains and the protective earth cannot be accepted by the following countries: * pluggable equipment type A: Austria, Belgium, Denmark, Finland, Norway, Sweden, UK pluggable equipment type B: Belgium, Denmark, Norway, UK A combination of a varistor in series with a spark gap (gas tube,) complying with basic insulation, and with a fuse will be accepted for: a) pluggable equipment type B and permanently connected equipment: * by all countries b) pluggable equipment type A: * by all countries except Denmark, UK, and Sweden For pluggable equipment type A two fuses are required. (to ensure that even by non-polarized plugs a fuse is provided) Permanently connected equipment connected to protective earth: * accepted by all countries - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Varistors to ground
This information is very timely since I am currently working on a project that requires varistors to ground. The varistors are not approved. How does one size the spark gap firing voltage and the fuse value? I am concerned with the fuse opening when the equipment sees a transient. Also, if the equipment contains a circuit breaker, is the fuse necessary? Thanks, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. -Original Message- From: Volker Gasse [mailto:ga...@de.ibm.com] Sent: Tuesday, December 15, 1998 3:34 AM To: emc-p...@majordomo.ieee.org Subject: RE: Varistors to ground The mentioned Cenelec decision is taken from the 'List of decisions from CENELEC Operational Staff Meeting for Electronic Equipment (OSM/EE)'. Here representatives from EU Testhouses meet to discuss interpretations of clauses in safety standards such as EN 60950 for IT products. These decisions are to be followed by all European testhouses. However, those decisions should be interpretations/clarifications to the existing standards, but not addition of new requirements. For EN 60950, Clause 1.5.1, Decision 98/2 states: 'A combination of a varistor in series with a spark gap (Gas-Tube) [between the mains and the protective earth] complying with Basic Insulation, and with a fuse will be accepted for a. Pluggable equipment Type B and permanently connected equipment: by all countries b. Pluggable equipment Type A: by all countries except DK, UK and SE. For pluggable equipment Type A two fuses are required.' (To be sure that even by non-polarized plugs a fuse is provided) This interpretation is an extension to a decision which was already issued in 1/94: 'If a Varistor is separately approved according to Publications IEC 601051-1 and IEC 601051-2, it can be accepted without a protective device. If a Varistor is not separately approved, a protective device against the short-circuit is required. Varistors tested according to CECC 42200 are considered as acceptable in the same way as tested to IEC 601051. Varistors between the mains and the protective earth cannot be accepted by the following countries: Pluggable equipment, type A: Austria, Belgium, Denmark, Finland, Norway, Sweden, United Kingdom.' The new decision is not part of the upcoming safety standard for IT products, IEC 60950 3rd edition, which is likely to be available beginning of next year. One of the reasons for requiring the spark gap in series with the varistor is a possible increase in leakage current if the varistor has been exposed to several mains transients. It should be noted, that IEC/EN 60950 does not require the use of transient suppressing components. Concerning the mit freundlichen Gruessen/ best regards Volker Gasse IBM Germany, Technical Relations/Product Safety, Tel: +49 7031-16-6796, Fax: -6916, e-mail: ga...@de.ibm.com Mail: 3114/7103-91, D-70548 Stuttgart, Germany -- Forwarded by Volker Gasse/Germany/IBM on 15.12.98 11:20 --- owner-emc-p...@majordomo.ieee.org on 15.12.98 02:11:00 Please respond to jeich...@statpower.com To: j...@bighorn.dr.lucent.com cc: emc-p...@majordomo.ieee.org Subject: RE: Varistors to ground John: Sorry I can't help, but I am interested in what replies you get. I also wonder what force the Decision carries. Is it a mandatory part of the Low Voltage Directive? How does it relate to the LVD or to the various EN's in force under the LVD? Thanks in advance for any light you can shed on these murky waters! Regards, Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: Boucher, John [SMTP:j...@bighorn.dr.lucent.com] Sent: Monday, December 14, 1998 9:07 AM To: 'emc-p...@ieee.org' Subject: Varistors to ground All: I have received a copy of a CENELEC Decision (dated 6/98) regarding the use of varistors between mains conductors and ground. This particular Decision is written in a rather unclear fashion (at least its unclear to me...I tend to be rather literal in my interpretations of written requirements), and I am struggling with defining the actual requirements. If anyone out there has received this Decision, and believes they are clear about what the actual bottom line requirements are, please let me know. I have muddled through some of the issues, but need some confirmation on a couple of points (see the questions below). It may seem to some that the answers to these questions are straight-forward in the Decision, but I have studied this Decision (maybe too much) and find these points unclear. 1) Is this Decision only for pluggable equipment type A, or is the spark-gap / fuse requirement in effect
Re: Varistors to ground
Hello; I appreciate the discussions and information gained. Can any point me to where on the Web I can get copies of CENELEC Decisions such the referenced CENELEC Decision (dated 6/98)? Thanks, Ray Hulinsky RCIC - http://www.rcic.com Regulatory Compliance Information Center - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Varistors to ground
You have raised an interesting question, especially in light of CE marking. Once a CE marked product is placed on the EU market, there are no further restrictions to limit its distribution or use in other member states. I do not think it is possible to restrict usage in one specific country based on an information in the users guide, especially if safety is involved. In other cases of country specific restrictions, like 'Special National Conditions' in European Norms, the design has to cover all of them to be able to state compliance to this standard and to apply CE marking. mit freundlichen Gruessen/ best regards Volker Gasse IBM Germany, Technical Relations/Product Safety, Tel: +49 7031-16-6796, Fax: -6916, e-mail: ga...@de.ibm.com Mail: 3114/7103-91, D-70548 Stuttgart, Germany owner-emc-p...@majordomo.ieee.org on 15.12.98 22:52:54 Please respond to wo...@sensormatic.com To: emc-p...@majordomo.ieee.org cc: Subject: RE: Varistors to ground Volker, thank you for this useful information. You indicated that the decisions are to be followed by all of the test houses, yet many of the decisions appear to be accepted in only some countries. If all of the test houses are expected to follow the decision, why are country exceptions allowed and what does it mean to us designers? - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Varistors to ground
Hello Jim, there is currently work ongoing in IEC TC74 to include requirements for varistors into IEC 60950. However, until those proposals have reached a level to be included into an amendment of the 3rd edition may take a while. I understand that varistors without fuses and sparc gaps in series are only allowed if separately approved as mentioned, and with the indicated country limitations. mit freundlichen Gruessen/ best regards Volker Gasse IBM Germany, Technical Relations/Product Safety, Tel: +49 7031-16-6796, Fax: -6916, e-mail: ga...@de.ibm.com Mail: 3114/7103-91, D-70548 Stuttgart, Germany owner-emc-p...@majordomo.ieee.org on 16.12.98 02:55:01 Please respond to jeich...@statpower.com To: emc-p...@majordomo.ieee.org cc: Subject: RE: Varistors to ground Volker: Thanks for the explanation. I am left with 2 questions: 1. You wrote The new decision is not part of the upcoming safety standard for IT products, IEC 60950 3rd edition, which is likely to be available beginning of next year. What does that omission tell us? If the 3rd edition has been written by people aware of the OSM/EE decisions, who consciously did not include the decisions in the new edition, then do they mean that varistors to ground are acceptable and not subject to the requirements in the 2 decisions you quoted? 2. It isn't clear whether the recent decision allows a varistor approved to IEC 601051-1 without a spark gap and fuse or whether the new decision overrules the old decision in this respect. Thanks again for any clarification anyone can offer. Regards, Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: Volker Gasse [SMTP:ga...@de.ibm.com] Sent: Tuesday, December 15, 1998 2:34 AM To: emc-p...@majordomo.ieee.org Subject: RE: Varistors to ground The mentioned Cenelec decision is taken from the 'List of decisions from CENELEC Operational Staff Meeting for Electronic Equipment (OSM/EE)'. Here representatives from EU Testhouses meet to discuss interpretations of clauses in safety standards such as EN 60950 for IT products. These decisions are to be followed by all European testhouses. However, those decisions should be interpretations/clarifications to the existing standards, but not addition of new requirements. For EN 60950, Clause 1.5.1, Decision 98/2 states: 'A combination of a varistor in series with a spark gap (Gas-Tube) [between the mains and the protective earth] complying with Basic Insulation, and with a fuse will be accepted for a. Pluggable equipment Type B and permanently connected equipment: by all countries b. Pluggable equipment Type A: by all countries except DK, UK and SE. For pluggable equipment Type A two fuses are required.' (To be sure that even by non-polarized plugs a fuse is provided) This interpretation is an extension to a decision which was already issued in 1/94: 'If a Varistor is separately approved according to Publications IEC 601051-1 and IEC 601051-2, it can be accepted without a protective device. If a Varistor is not separately approved, a protective device against the short-circuit is required. Varistors tested according to CECC 42200 are considered as acceptable in the same way as tested to IEC 601051. Varistors between the mains and the protective earth cannot be accepted by the following countries: Pluggable equipment, type A: Austria, Belgium, Denmark, Finland, Norway, Sweden, United Kingdom.' The new decision is not part of the upcoming safety standard for IT products, IEC 60950 3rd edition, which is likely to be available beginning of next year. One of the reasons for requiring the spark gap in series with the varistor is a possible increase in leakage current if the varistor has been exposed to several mains transients. It should be noted, that IEC/EN 60950 does not require the use of transient suppressing components. Concerning the mit freundlichen Gruessen/ best regards Volker Gasse IBM Germany, Technical Relations/Product Safety, Tel: +49 7031-16-6796, Fax: -6916, e-mail: ga...@de.ibm.com Mail: 3114/7103-91, D-70548 Stuttgart, Germany -- Forwarded by Volker Gasse/Germany/IBM on 15.12.98 11:20 --- owner-emc-p...@majordomo.ieee.org on 15.12.98 02:11:00 Please respond to jeich...@statpower.com To: j...@bighorn.dr.lucent.com cc: emc-p...@majordomo.ieee.org Subject: RE: Varistors to ground John: Sorry I can't help, but I am interested in what replies you get. I also wonder what force the Decision carries. Is it a mandatory part of the Low Voltage Directive? How does it relate to the LVD or to the various EN's in force under the LVD? Thanks in advance for any light you can shed on these murky waters! Regards, Jim Eichner Statpower Technologies Corporation jeich
RE: Varistors to ground
Volker: Thanks for the explanation. I am left with 2 questions: 1. You wrote The new decision is not part of the upcoming safety standard for IT products, IEC 60950 3rd edition, which is likely to be available beginning of next year. What does that omission tell us? If the 3rd edition has been written by people aware of the OSM/EE decisions, who consciously did not include the decisions in the new edition, then do they mean that varistors to ground are acceptable and not subject to the requirements in the 2 decisions you quoted? 2. It isn't clear whether the recent decision allows a varistor approved to IEC 601051-1 without a spark gap and fuse or whether the new decision overrules the old decision in this respect. Thanks again for any clarification anyone can offer. Regards, Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: Volker Gasse [SMTP:ga...@de.ibm.com] Sent: Tuesday, December 15, 1998 2:34 AM To: emc-p...@majordomo.ieee.org Subject: RE: Varistors to ground The mentioned Cenelec decision is taken from the 'List of decisions from CENELEC Operational Staff Meeting for Electronic Equipment (OSM/EE)'. Here representatives from EU Testhouses meet to discuss interpretations of clauses in safety standards such as EN 60950 for IT products. These decisions are to be followed by all European testhouses. However, those decisions should be interpretations/clarifications to the existing standards, but not addition of new requirements. For EN 60950, Clause 1.5.1, Decision 98/2 states: 'A combination of a varistor in series with a spark gap (Gas-Tube) [between the mains and the protective earth] complying with Basic Insulation, and with a fuse will be accepted for a. Pluggable equipment Type B and permanently connected equipment: by all countries b. Pluggable equipment Type A: by all countries except DK, UK and SE. For pluggable equipment Type A two fuses are required.' (To be sure that even by non-polarized plugs a fuse is provided) This interpretation is an extension to a decision which was already issued in 1/94: 'If a Varistor is separately approved according to Publications IEC 601051-1 and IEC 601051-2, it can be accepted without a protective device. If a Varistor is not separately approved, a protective device against the short-circuit is required. Varistors tested according to CECC 42200 are considered as acceptable in the same way as tested to IEC 601051. Varistors between the mains and the protective earth cannot be accepted by the following countries: Pluggable equipment, type A: Austria, Belgium, Denmark, Finland, Norway, Sweden, United Kingdom.' The new decision is not part of the upcoming safety standard for IT products, IEC 60950 3rd edition, which is likely to be available beginning of next year. One of the reasons for requiring the spark gap in series with the varistor is a possible increase in leakage current if the varistor has been exposed to several mains transients. It should be noted, that IEC/EN 60950 does not require the use of transient suppressing components. Concerning the mit freundlichen Gruessen/ best regards Volker Gasse IBM Germany, Technical Relations/Product Safety, Tel: +49 7031-16-6796, Fax: -6916, e-mail: ga...@de.ibm.com Mail: 3114/7103-91, D-70548 Stuttgart, Germany -- Forwarded by Volker Gasse/Germany/IBM on 15.12.98 11:20 --- owner-emc-p...@majordomo.ieee.org on 15.12.98 02:11:00 Please respond to jeich...@statpower.com To: j...@bighorn.dr.lucent.com cc: emc-p...@majordomo.ieee.org Subject: RE: Varistors to ground John: Sorry I can't help, but I am interested in what replies you get. I also wonder what force the Decision carries. Is it a mandatory part of the Low Voltage Directive? How does it relate to the LVD or to the various EN's in force under the LVD? Thanks in advance for any light you can shed on these murky waters! Regards, Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: Boucher, John [SMTP:j...@bighorn.dr.lucent.com] Sent: Monday, December 14, 1998 9:07 AM To: 'emc-p...@ieee.org' Subject: Varistors to ground All: I have received a copy of a CENELEC Decision (dated 6/98) regarding the use of varistors between mains conductors and ground. This particular Decision is written in a rather unclear fashion (at least its unclear to me...I tend to be rather literal in my interpretations of written requirements), and I am struggling with defining the actual requirements. If anyone out there has received
RE: Varistors to ground
Volker, thank you for this useful information. You indicated that the decisions are to be followed by all of the test houses, yet many of the decisions appear to be accepted in only some countries. If all of the test houses are expected to follow the decision, why are country exceptions allowed and what does it mean to us designers? - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Varistors to ground
The mentioned Cenelec decision is taken from the 'List of decisions from CENELEC Operational Staff Meeting for Electronic Equipment (OSM/EE)'. Here representatives from EU Testhouses meet to discuss interpretations of clauses in safety standards such as EN 60950 for IT products. These decisions are to be followed by all European testhouses. However, those decisions should be interpretations/clarifications to the existing standards, but not addition of new requirements. For EN 60950, Clause 1.5.1, Decision 98/2 states: 'A combination of a varistor in series with a spark gap (Gas-Tube) [between the mains and the protective earth] complying with Basic Insulation, and with a fuse will be accepted for a. Pluggable equipment Type B and permanently connected equipment: by all countries b. Pluggable equipment Type A: by all countries except DK, UK and SE. For pluggable equipment Type A two fuses are required.' (To be sure that even by non-polarized plugs a fuse is provided) This interpretation is an extension to a decision which was already issued in 1/94: 'If a Varistor is separately approved according to Publications IEC 601051-1 and IEC 601051-2, it can be accepted without a protective device. If a Varistor is not separately approved, a protective device against the short-circuit is required. Varistors tested according to CECC 42200 are considered as acceptable in the same way as tested to IEC 601051. Varistors between the mains and the protective earth cannot be accepted by the following countries: Pluggable equipment, type A: Austria, Belgium, Denmark, Finland, Norway, Sweden, United Kingdom.' The new decision is not part of the upcoming safety standard for IT products, IEC 60950 3rd edition, which is likely to be available beginning of next year. One of the reasons for requiring the spark gap in series with the varistor is a possible increase in leakage current if the varistor has been exposed to several mains transients. It should be noted, that IEC/EN 60950 does not require the use of transient suppressing components. Concerning the mit freundlichen Gruessen/ best regards Volker Gasse IBM Germany, Technical Relations/Product Safety, Tel: +49 7031-16-6796, Fax: -6916, e-mail: ga...@de.ibm.com Mail: 3114/7103-91, D-70548 Stuttgart, Germany -- Forwarded by Volker Gasse/Germany/IBM on 15.12.98 11:20 --- owner-emc-p...@majordomo.ieee.org on 15.12.98 02:11:00 Please respond to jeich...@statpower.com To: j...@bighorn.dr.lucent.com cc: emc-p...@majordomo.ieee.org Subject: RE: Varistors to ground John: Sorry I can't help, but I am interested in what replies you get. I also wonder what force the Decision carries. Is it a mandatory part of the Low Voltage Directive? How does it relate to the LVD or to the various EN's in force under the LVD? Thanks in advance for any light you can shed on these murky waters! Regards, Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: Boucher, John [SMTP:j...@bighorn.dr.lucent.com] Sent: Monday, December 14, 1998 9:07 AM To: 'emc-p...@ieee.org' Subject: Varistors to ground All: I have received a copy of a CENELEC Decision (dated 6/98) regarding the use of varistors between mains conductors and ground. This particular Decision is written in a rather unclear fashion (at least its unclear to me...I tend to be rather literal in my interpretations of written requirements), and I am struggling with defining the actual requirements. If anyone out there has received this Decision, and believes they are clear about what the actual bottom line requirements are, please let me know. I have muddled through some of the issues, but need some confirmation on a couple of points (see the questions below). It may seem to some that the answers to these questions are straight-forward in the Decision, but I have studied this Decision (maybe too much) and find these points unclear. 1) Is this Decision only for pluggable equipment type A, or is the spark-gap / fuse requirement in effect for pluggable equipment type B as well? 2) Will Denmark, UK, and Sweden accept varistors to ground if the circuit contains a spark-gap and two fuses? 3) The installation instructions for our PABX systems include the requirement for a permanently connected ground wire between the equipment ground and an approved building ground (this ground wire is in addition to the green wire lead in the AC mains). This wire is required for all our PABX systems (AC and DC powered systems, pluggable type A, type B, and permanently connected systems). Does this permanent ground connection provide an exemption to this Decision? If this Decision means DK, UK, SE will simply not accept varistors to ground, then a lot of small pluggable type A equipment intended
RE: Varistors to ground
John: Sorry I can't help, but I am interested in what replies you get. I also wonder what force the Decision carries. Is it a mandatory part of the Low Voltage Directive? How does it relate to the LVD or to the various EN's in force under the LVD? Thanks in advance for any light you can shed on these murky waters! Regards, Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: Boucher, John [SMTP:j...@bighorn.dr.lucent.com] Sent: Monday, December 14, 1998 9:07 AM To: 'emc-p...@ieee.org' Subject: Varistors to ground All: I have received a copy of a CENELEC Decision (dated 6/98) regarding the use of varistors between mains conductors and ground. This particular Decision is written in a rather unclear fashion (at least its unclear to me...I tend to be rather literal in my interpretations of written requirements), and I am struggling with defining the actual requirements. If anyone out there has received this Decision, and believes they are clear about what the actual bottom line requirements are, please let me know. I have muddled through some of the issues, but need some confirmation on a couple of points (see the questions below). It may seem to some that the answers to these questions are straight-forward in the Decision, but I have studied this Decision (maybe too much) and find these points unclear. 1) Is this Decision only for pluggable equipment type A, or is the spark-gap / fuse requirement in effect for pluggable equipment type B as well? 2) Will Denmark, UK, and Sweden accept varistors to ground if the circuit contains a spark-gap and two fuses? 3) The installation instructions for our PABX systems include the requirement for a permanently connected ground wire between the equipment ground and an approved building ground (this ground wire is in addition to the green wire lead in the AC mains). This wire is required for all our PABX systems (AC and DC powered systems, pluggable type A, type B, and permanently connected systems). Does this permanent ground connection provide an exemption to this Decision? If this Decision means DK, UK, SE will simply not accept varistors to ground, then a lot of small pluggable type A equipment intended for sale in DK, UK, SE will have to either: 1) discontinue using varistors, or 2) become pluggable equipment type B (which would be onerous, given the IEC 309 plugs I've seen). Thanks for the help. John Boucher jpbouc...@lucent.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Varistors to ground
All: I have received a copy of a CENELEC Decision (dated 6/98) regarding the use of varistors between mains conductors and ground. This particular Decision is written in a rather unclear fashion (at least its unclear to me...I tend to be rather literal in my interpretations of written requirements), and I am struggling with defining the actual requirements. If anyone out there has received this Decision, and believes they are clear about what the actual bottom line requirements are, please let me know. I have muddled through some of the issues, but need some confirmation on a couple of points (see the questions below). It may seem to some that the answers to these questions are straight-forward in the Decision, but I have studied this Decision (maybe too much) and find these points unclear. 1) Is this Decision only for pluggable equipment type A, or is the spark-gap / fuse requirement in effect for pluggable equipment type B as well? 2) Will Denmark, UK, and Sweden accept varistors to ground if the circuit contains a spark-gap and two fuses? 3) The installation instructions for our PABX systems include the requirement for a permanently connected ground wire between the equipment ground and an approved building ground (this ground wire is in addition to the green wire lead in the AC mains). This wire is required for all our PABX systems (AC and DC powered systems, pluggable type A, type B, and permanently connected systems). Does this permanent ground connection provide an exemption to this Decision? If this Decision means DK, UK, SE will simply not accept varistors to ground, then a lot of small pluggable type A equipment intended for sale in DK, UK, SE will have to either: 1) discontinue using varistors, or 2) become pluggable equipment type B (which would be onerous, given the IEC 309 plugs I've seen). Thanks for the help. John Boucher jpbouc...@lucent.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
