Re: Protective Earthing Terminal Construction Requirements
This message has been converted via the evaluation version of Transend Migrator. Use beyond the trial period specified in your Software Evaluation Agreement is prohibited. Please contact Transend Corporation at (650) 324-5370 or sales.i...@transend.com to obtain a license suitable for use in a production environment. Thank you. br -br In message 558320.76575...@web35403.mail.mud.yahoo.com, dated Sun, 16 Mar 2008, Joel Sandberg jbsandt...@yahoo.com writes: I have searched 60601-1:1988 and 60950:95 looking for requirements and a diagram. Both of those are VERY out-of-date. For example, in IEC 60950-1:2002, see clauses 2.6.4 and 3.3. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Protective Earthing Terminal Construction Requirements
This message has been converted via the evaluation version of Transend Migrator. Use beyond the trial period specified in your Software Evaluation Agreement is prohibited. Please contact Transend Corporation at (650) 324-5370 or sales.i...@transend.com to obtain a license suitable for use in a production environment. Thank you. br -br Hello Joel, IEC/EN 60335-1 has a diagram (figure 10) indicating ‘example’ parts of an earthing terminal. It distinguishes parts providing earthing continuity from parts providing or transmitting contact pressure. Generally most product safety standards (including 60335) do not specify ‘explicit’ construction requirements for protective earthing connections only that certain requirements shall be met. An issue that can sometimes be overlooked is that of not double fixing when crimping a connector onto an earth wire – ideally the conductor AND the insulation should be fixed. I have never seen this explicitly stated but it goes with the ‘spirit’ of most product safety standards and good engineering practice. I will see if I can extract the diagram. Best regards, ___ Steve Richardson Blackwood Compliance Laboratories Unit 8 Woodfieldside Business Park Pontllanfraith Blackwood NP12 2DG United Kingdom Tel: +44(0)1495 229219 Fax: +44(0)1495 228331 www.blackwood-labs.co.uk http://www.blackwood-labs.co.uk/ Limited places available *** EMC seminar - Millennium Stadium Cardiff *** http://www.blackwood-labs.co.uk/trainingcourses Click here or visit http://www.blackwood-labs.co.uk/trainingcourses www.blackwood-labs.co.uk/trainingcourses From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Joel Sandberg Sent: 17 March 2008 02:37 To: emc-p...@ieee.org Subject: Protective Earthing Terminal Construction Requirements To Members of the Product Safety Group; I am trying to find the construction requirements, and the standards that set these requirements, for a protective earth(ing) terminal. Many of us have learned that there needs to be locking washers and nuts between each ring lug. But where is this actually called out and required? I am trying to show the engineering department were I work which parts of this good practice are actually requirements of the requirements we will be claiming to meet. I have found a diagram at www.phihong/html/grounding.html (Phihong.com) that shows reasonable grounding technique. But this web site does not site any standard as a basis for the technique. I have searched 60601-1:1988 and 60950:95 looking for requirements and a diagram. I have found resistance requirements, 0.1 ohm max in 60601-1, section 18 f), but I can not find construction explicit requirements. Does anyone know if any standard includes explicit construction requirements for a protective earth terminal and for connections to a PE terminal? Thank you. Joel Sandberg Lake Worth, FL _ Looking for last minute shopping deals? Find http://us.rd.yahoo.com/evt=51734/*http /tools.search.yahoo.com/newsearch/category.php?category=shopping them fast with Yahoo! Search. - - -- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing Terminal Construction Requirements
In message 004f01c8885e$4d6a61e0$0500a8c0@Pete97219Compaq, dated Mon, 17 Mar 2008, Pete Perkins peperkin...@cs.com writes: Further, standards keep moving to a performance based set of requirements rather than a construction based set. Yes. For example, the IEC 60335-1 provision doesn't include a riveted attachment. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Protective Earthing Terminal Construction Requirements
Joel, et al, Many great comments have been made in this discussion so far; thanx to the PSNet folks experience being shared here. From an operational point of view equipment either depends upon earthing (the second level of protection after the basic insulation) or double insulation for protection from electric shock. We have come to learn from our lengthy discussions in developing the new Hazard Based standard that there are conditions which are outside the control of the equipment manufacturer and, when they occur, are abnormal situations. The availability of earth is one of these; it may not be properly connected in some situations or it may not be provided (such as in Japan or Netherlands or Norway) because of the local electrical system codes and practice. In either case our standards limit the current in the earthing conductor to prevent hazardous electric shock. The connection within the equipment must be robust and not accidentally defeated during maintenance or repair. The use of a single earthing connection for the principle ground is appropriate here. The use of lockwahsers and double nuts is another good practice for additional connections where they cannot be independently done. Further, standards keep moving to a performance based set of requirements rather than a construction based set. This makes it difficult to pass good practice along in our business. So we need to listen to the experienced practitioners and carry these good practices along. This is not as satisfying as being able to point out the specific wording in your standard, but it makes good sense solutions for many cases. :) br, Pete Peter E Perkins, PO Box 23427 Tigard, ORe 97281-3427 503/452-1201 fone/fax p.perk...@ieee.org - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Protective Earthing Terminal Construction Requirements
From: Joel Sandberg Sent: Sunday, March 16, 2008 7:37 PM Many of us have learned that there needs to be locking washers and nuts between each ring lug. But where is this actually called out and required? Good morning, Joel. While it isn't obvious from the wording, IEC 60950-1:2005 contains the requirement in Subclause 2.6.4.3. It took a committee to begin with a very simple idea and come up with this text. There doesn't appear to be a similar requirement in IEC 60601-1:1998. While not addressing a single piece of medical electrical equipment, IEC 60601-1:2005, Subclause 16.9.2.2 contains very simple verbiage for medical electrical system protective earthing connections, that conveys the concept, as it might be applied to a single piece of equipment. Regards, Peter L. Tarver, PE Manager - Product Safety Sanmina-SCI Corp. 2000 Ringwood Ave. San Jose, CA 95131-1723 V: +1-408-904-2081 F: +1-408-904-2095 M: +1-408-234-3529 CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing Terminal Construction Requirements
Hello Chris To fulfill requirements of risk management according to ISO 14971, you have to identify all the hazard situations whhich could turn a hazard into harm. This means identifying all the foreseeable sequence or combinations of events that could led to the hazard situation. Three points here: First: sometimes people think that they only have to identify the hazard (for example, electrical shock). But there are a lot of situations (probabilities) in which this hazard could arise, and there are a lot of outcomes (severities) if the hazard turn into harm. So you have to determine the risks of each hazard situation, not only of the more general hazard. Second point: Foreseeable. It means that, although theoretically there are an infinite number of hazard situations, you still have to limit it to some number to keep it manageable. In fact, where to stop really depends on manufacturer. It should be noted that there are some technoques for doing this, for example, taking into consideration the intented use and reasonably foreseeable misuse as initial parameters. Third: although IEC safety product standard (in which the IEC 60601 series are an example of) follow the single fault philosophy, ISO 14971 is not restricted to single faults. So yes, there could have doube or triple faults on your risk management (but try to use just the foreseeable ones, please:-)). Also, it´s always toog to keep in mind that the single fault philosophy in IEC 60601 can only be applied if the situation falls under some specific boundaries (these boundaries are explanied in the examplanation to 4.7 in Annex A). If the situation are outside these boundaries, then the single fault philosophy cannot be aplied. For more on this interaction i suggest the following paper: R.G. Mellish, The single fault philosophy: How it fits with risk. management,presented at ACOS Workshop VI, Safety of Electromedical Equipment—An Integrated Approach through IEC Standards, Toronto, May 6–7, 1998. Cheers! Best regards Marcelo Antunes Regulatory strategy consultant SQR Consulting - Safety and quality through risk management http://www.sqrconsulting.com.br http://www.sqrconsulting.com.br/ Electromedicalinfo http://www.electromedicalinfo.com http://www.electromedicalinfo.com/ Gtalk: mmantu...@gmail.com MSN: marcelo_antu...@hotmail.com - Show quoted text - Chris.Dupres@elek ta.com To 03/17/2008 09:06 ted.eck...@apcc.com AM cc emc-p...@ieee.org Subject Re: Protective Earthing Terminal Construction Requirements Ted Ekert said: If a ground connection fails, there will be no indication of a problem to the user. The product will likely continue to operate perfectly normally. A second failure, such as a loose line wire, could lead to the sudden and unexpected energizing of exposed metal. The product has now become hazardous without warning. This makes sense of course, but (going off track a little bit) this implies that the equipment has TWO faults, and the premise at the moment seems to be 'Safety under SINGLE FAULT conditions'. I guess I'm asking for opinions, in view of the latest standards leaning or Risk Analysis etc., (e.g. IEC 60601-1 Rev 3) is.. How many stacked risks should we take into account? when defining 'Risk'. I mean, it's perfectly feasible to lose a ground connection on a case (1 fault), and for a live wire to come loose and touch the case (2 fault). Do we have to take ALL scenario's like that into account? In other words, ensure the design is safe under double, or even triple fault conditions? I'm reminded of a mains plug on a piece of UK equipment, where the lead was tugged, the Earth wire pulled out and ended up on the Live wire. Of course the whole case became live.This was found because a secretary felt a 'tingle' when she touched the case. I guess her plastic high heels saved her that time. One event, but two faults. So how many levels of fault should we take into account in order to fulfil the Risk Analysis requirements? Regards, Chris. Chris Duprés Compliance Engineer Elekta Limited Linac House Fleming Way Crawley West Sussex RH10 9RR www.elekta.com tel: +44 (0) 1293 654311 fax: +44 (0) 1293 654260 ***Internet Email Confidentiality Footer*** The contents of this e-mail message (including any attachments hereto) are confidential to and are intended to be conveyed for the use of the recipient to whom it is addressed only. If you receive this transmission in error, please notify the sender of this immediately and delete the message from your system. Any distribution, reproduction or use
Re: Protective Earthing Terminal Construction Requirements
In message off00330a3.388a0ed2-on8625740f.004dd2de-8625740f.00504...@apcc.com, dated Mon, 17 Mar 2008, ted.eck...@apcc.com writes: The loss of the ground connection is treated differently because it is virtually undetectable under normal conditions of use. It isn't the only undetectable fault, either. I agree that a single fault has occurred, but the user doesn't know it. The product could be used for years in this state until there is a second fault which could then energize the chassis can cause injury. Yes. The product is used as if no fault has occurred, so I would treat the next fault that happens as a single fault. I don't think that is logical, and it makes explaining the situation virtually impossible. I tried to get a statement about 'persistent undetectable fault' and 'subsequent unrelated fault' into IEC 60065, but there was not enough support. It's difficult to write about it without verging on scaremongering. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing Terminal Construction Requirements
In message of069c78e9.ebe4325a-on8025740f.004c2169-8025740f.004d8...@elekta.com, dated Mon, 17 Mar 2008, chris.dup...@elekta.com writes: So how many levels of fault should we take into account in order to fulfil the Risk Analysis requirements? This is one of those questions that no-one wants to answer. So I'll try. The reason that there isn't any 'official' answer is that with more than one simultaneous fault, chosen from all possible faults, nothing could ever be considered 'safe'. So, what you have to do is consider the consequences. If a fault creates a 'high risk' condition, then take care that its probability is very low. This is the case for the protective conductor connection of Class I equipment. However, it is a principle of standardization that specification of performance is much preferred to specifying design or construction. IEC 60335 has specified construction in this respect for a very long time, probably since before the above principle was recognized. Also, many household appliances generate their own vibration, which other products don't, so the need for a secure fixing is particularly great. Yet again, household appliances are still repairable items, so the service technician should not be easily able to forget to replace protective conductor connections. But ICT and multimedia equipment are less likely to be repaired these days, and technician training is better anyway, so the probability of an omitted connection is less. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing Terminal Construction Requirements
Hello Chris, The general rule is to test under single fault conditions. However, the loss of a ground connection is different from most other faults. The ground can be lost without any normal means of detection for the user. Most other faults will trip a fuse or render the product at least partially inoperable. When the ground wire is lost, the product will likely continue to be used as if there were no fault at all. The loss of the ground connection is treated differently because it is virtually undetectable under normal conditions of use. I agree that a single fault has occurred, but the user doesn't know it. The product could be used for years in this state until there is a second fault which could then energize the chassis can cause injury. The product is used as if no fault has occurred, so I would treat the next fault that happens as a single fault. Ted Eckert American Power Conversion/MGE http://www.apc.com/ The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC-MGE or Schneider Electric. The speaker does not represent APC-MGE's or Schneider Electric's official position on any matter. Chris.Dupres@elek ta.com To 03/17/2008 09:06 ted.eck...@apcc.com AM cc emc-p...@ieee.org Subject Re: Protective Earthing Terminal Construction Requirements Ted Ekert said: If a ground connection fails, there will be no indication of a problem to the user. The product will likely continue to operate perfectly normally. A second failure, such as a loose line wire, could lead to the sudden and unexpected energizing of exposed metal. The product has now become hazardous without warning. This makes sense of course, but (going off track a little bit) this implies that the equipment has TWO faults, and the premise at the moment seems to be 'Safety under SINGLE FAULT conditions'. I guess I'm asking for opinions, in view of the latest standards leaning or Risk Analysis etc., (e.g. IEC 60601-1 Rev 3) is.. How many stacked risks should we take into account? when defining 'Risk'. I mean, it's perfectly feasible to lose a ground connection on a case (1 fault), and for a live wire to come loose and touch the case (2 fault). Do we have to take ALL scenario's like that into account? In other words, ensure the design is safe under double, or even triple fault conditions? I'm reminded of a mains plug on a piece of UK equipment, where the lead was tugged, the Earth wire pulled out and ended up on the Live wire. Of course the whole case became live.This was found because a secretary felt a 'tingle' when she touched the case. I guess her plastic high heels saved her that time. One event, but two faults. So how many levels of fault should we take into account in order to fulfil the Risk Analysis requirements? Regards, Chris. Chris Duprés Compliance Engineer Elekta Limited Linac House Fleming Way Crawley West Sussex RH10 9RR www.elekta.com tel: +44 (0) 1293 654311 fax: +44 (0) 1293 654260 ***Internet Email Confidentiality Footer*** The contents of this e-mail message (including any attachments hereto) are confidential to and are intended to be conveyed for the use of the recipient to whom it is addressed only. If you receive this transmission in error, please notify the sender of this immediately and delete the message from your system. Any distribution, reproduction or use of this message by someone other than recipient is not authorized and may be unlawful. Elekta Limited is a company registered in England and Wales whose registered number is 3244454 and whose registered address is Linac House, Fleming Way, Crawley, West Sussex, RH10 9RR - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message
Re: Protective Earthing Terminal Construction Requirements
Ted Ekert said: If a ground connection fails, there will be no indication of a problem to the user. The product will likely continue to operate perfectly normally. A second failure, such as a loose line wire, could lead to the sudden and unexpected energizing of exposed metal. The product has now become hazardous without warning. This makes sense of course, but (going off track a little bit) this implies that the equipment has TWO faults, and the premise at the moment seems to be 'Safety under SINGLE FAULT conditions'. I guess I'm asking for opinions, in view of the latest standards leaning or Risk Analysis etc., (e.g. IEC 60601-1 Rev 3) is.. How many stacked risks should we take into account? when defining 'Risk'. I mean, it's perfectly feasible to lose a ground connection on a case (1 fault), and for a live wire to come loose and touch the case (2 fault). Do we have to take ALL scenario's like that into account? In other words, ensure the design is safe under double, or even triple fault conditions? I'm reminded of a mains plug on a piece of UK equipment, where the lead was tugged, the Earth wire pulled out and ended up on the Live wire. Of course the whole case became live.This was found because a secretary felt a 'tingle' when she touched the case. I guess her plastic high heels saved her that time. One event, but two faults. So how many levels of fault should we take into account in order to fulfil the Risk Analysis requirements? Regards, Chris. Chris Duprés Compliance Engineer Elekta Limited Linac House Fleming Way Crawley West Sussex RH10 9RR www.elekta.com tel: +44 (0) 1293 654311 fax: +44 (0) 1293 654260 ***Internet Email Confidentiality Footer*** The contents of this e-mail message (including any attachments hereto) are confidential to and are intended to be conveyed for the use of the recipient to whom it is addressed only. If you receive this transmission in error, please notify the sender of this immediately and delete the message from your system. Any distribution, reproduction or use of this message by someone other than recipient is not authorized and may be unlawful. Elekta Limited is a company registered in England and Wales whose registered number is 3244454 and whose registered address is Linac House, Fleming Way, Crawley, West Sussex, RH10 9RR - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing Terminal Construction Requirements
Hello Joel, The ground connection is treated differently from other terminals because of what happens if it fails. If a line connection comes loose, there should be some indication of a problem. The equipment will likely not operate properly or it will operate at a reduced capacity of some type. The earthed chassis of Class I equipment, or the double insulation of Class II equipment will protect the user from this failure. The indication of the problem should prompt the user to remove the product from service for repair. I realize that this doesn't always happen, but at least the user has been given some indication that there is a problem and it is now up to them to take action. If a ground connection fails, there will be no indication of a problem to the user. The product will likely continue to operate perfectly normally. A second failure, such as a loose line wire, could lead to the sudden and unexpected energizing of exposed metal. The product has now become hazardous without warning. I know that this is a generalization and we don't live in an ideal world. However, it is based on the concept of risk reduction. Adding a supplementary retention method to a ground connection can provide an additional level of safety. Ted Eckert American Power Conversion/MGE http://www.apc.com/ The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC-MGE or Schneider Electric. The speaker does not represent APC-MGE's or Schneider Electric's official position on any matter. Joel Sandberg jbsandtech@yahoo .com To Sent by: emc-p...@ieee.org emc-p...@ieee.org cc Subject 03/16/2008 09:36 Protective Earthing Terminal PMConstruction Requirements To Members of the Product Safety Group; I am trying to find the construction requirements, and the standards that set these requirements, for a protective earth(ing) terminal. Many of us have learned that there needs to be locking washers and nuts between each ring lug. But where is this actually called out and required? I am trying to show the engineering department were I work which parts of this good practice are actually requirements of the requirements we will be claiming to meet. I have found a diagram at www.phihong/html/grounding.html (Phihong.com) that shows reasonable grounding technique. But this web site does not site any standard as a basis for the technique. I have searched 60601-1:1988 and 60950:95 looking for requirements and a diagram. I have found resistance requirements, 0.1 ohm max in 60601-1, section 18 f), but I can not find construction explicit requirements. Does anyone know if any standard includes explicit construction requirements for a protective earth terminal and for connections to a PE terminal? Thank you. Joel Sandberg Lake Worth, FL Looking for last minute shopping deals? Find them fast with Yahoo! Search. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions:
Re: Protective Earthing
If the product has worldwide distribution, best to have protective earth in the manual since most countries have adopted IEC based standards. In the US, you will need to comply with the marking/instructions in the product specific standard. Most of the US based standards have unique grounding requirements - including having a green colored screw head, etc. I have seen many licensed electricians in the US, not referring to manuals when they install equipment which are intended for permanent connection to the supply. They do refer to the label with amperage rating and the field wiring compartment (typically marked with the type and temperature rating of the conductor (Use Copper or CU-AL conductors rated ___ deg C ) and looking for that green colored screw to connect the protective earth (or should I say grounding) conductor Peter Merguerian john.merr...@us.schneider-electric.com wrote: I have a case where some want to substitute the word Ground for Protective Earth in product manuals. The products are marked with IEC 5019a protective Earthing symbol and I have no trouble proving the requirements for that. It's in the manual where references to Wire Size of Protective Earthing conductor etc that some here want to change this to Ground. From the IEV 60050-195 the term ground is a Local US term and the manual has worldwide distribution in four languages. Any suggestions on where to find good arguments against doing this? Thanks in advance. John Merrill Product Safety Engineer Schneider Automation inc. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc _ Looking for last minute shopping deals? http://us.rd.yahoo.com/evt=51734/*http //tools.search.yahoo.com/newsearch/category.php?category=shopping Find them fast with Yahoo! Search. - --- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing
The latest 2008 NFPA 70 has redefined Ground as the earth as well as redefining some other grounding terms. The US code has continually been a source of confusion since it uses grounded and grounding to mean different things. This distinction is missed by many who are not familiar with the US codes. They recently editorially corrected lots of terms in the code just to try to gain consistency if not clarity. My preference has been to include some descriptive help when using the terms regarding their purpose, using Protective Grounding Conductor or Protective Earthing Conductor when meaning the green/yellow wire or circuit, and Grounded Neutral Conductor, Earthed Neutral Conductor or just Neutral Conductor when referring to the white or blue common power return circuit. I tend to use Grounding or Grounded when discussing with North Americans and Earthing or Earthed when discussing internationally. Bob Johnson ITE Safety http://www.itesafety.com ted.eck...@apcc.com wrote: I agree with John Woodgate that you may be best off using dual nomenclature. NFPA 70, the National Electrical Code, uses Ground and not Earth. The Canadian Electrical Code is the same. Neither defines Earth and both use it to refer to the dirt and rock beneath a structure, not an equipotential reference normally connected to the earth. I can also look at IEC 60950-1. Clause 1.2.13.10 defines Protective Earthing Conductor, but there is also a note for this clause which states In some countries, the term 'grounding conductor' is used instead of 'protective earthing conductor'. This note is not universal in IEC standards as I can not find the word ground anywhere in IEC 60335. Have you considered defining Ground or Earth in your manual so that the English language readers clearly understand to what you are referencing? The NEC defines Ground as A conducting connection, whether intentional or accidental, between an electrical circuit or equipment and the earth or to some conducting body that serves in place of the earth. This may be the place to start for a definition. Ted Eckert American Power Conversion/MGE http://www.apc.com/ The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC-MGE or Schneider Electric. The speaker does not represent APC-MGE's or Schneider Electric's official position on any matter. John Woodgate mailto:j...@jmwa.demon.co.uk jmw@jmwa.demon.c o.uk To Sent by: emc-p...@ieee.org emc-p...@ieee.org cc Subject 02/29/2008 11:09 Re: Protective Earthing AM In message mailto:OF991E870B.BC390323-ON852573FE 005aed36-852573fe.005be...@us.schneider-electric.com OF991E870B.BC390323-ON852573FE.005AED36-852573FE.005BEAFD@US.Schneider-E lectric.com, dated Fri, 29 Feb 2008, john.merr...@us.schneider-electric.com writes: I have a case where some want to substitute the word Ground for Protective Earth in product manuals. The products are marked with IEC 5019a protective Earthing symbol and I have no trouble proving the requirements for that. It's in the manual where references to Wire Size of Protective Earthing conductor etc that some here want to change this to Ground. From the IEV 60050-195 the term ground is a Local US term and the manual has worldwide distribution in four languages. Any suggestions on where to find good arguments against doing this? The best argument is that it is not 'either ...or...'. Only the English language is affected: I don't think there are similar variants in other languages. So the simplest solution is to print 'earth/ground' wherever necessary. Some people whose first language is not English have learned 'earth' and others have learned 'ground'. Since you have only four languages, there will be such people reading the English. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk
Re: Protective Earthing
In message 5f5a140eb5cb094bb4d2c477c8c4ad99aa9...@sjc1amfpew04.am.sanm.corp, dated Fri, 29 Feb 2008, Tarver, Peter peter.tar...@sanmina-sci.com writes: Well, then, by all means, those who insisted that 'earth' be used, instead of 'ground,' in the writing of all these IEC safety standards, needs to get in step with the rest of the world, instead of trying to make the world conform to their terminology. In fact, IEC allows the use of either British or US English, but only one in each standard, no mixing. I don't know of any special ruling regarding 'ground' - there is nothing like that in Directives Part 2, which is where it would be. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing
Even my kids know what grounded means. They don't get to use the phone or TV for the next three life times... John Woodgate j...@jmwa.demon.co.uk wrote: In message 5f5a140eb5cb094bb4d2c477c8c4ad99aa9...@sjc1amfpew04.am.sanm.corp, dated Fri, 29 Feb 2008, Tarver, Peter writes: If the product is deployed internationally, protective earth should be used. I'm not aware of anyone in the US or Canada who would misunderstand this term, if were not called 'ground.' Very likely, but 'ground' is also used all over the world by technicians whose first language is not English but who learned technical terms from American books. They are the ones who may well be confused by 'earth'. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - Bill You can say what you want about the South, but you never hear of anyone retiring and moving North!!! _ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. http://us.rd.yahoo.com/evt=51733/*http //mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ Try it now. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Protective Earthing
I have run into a few instances of problems. One was when I was at a union site that required a specific contractor even for work that didn't require a licensed electrician. I asked for an equipment rack to be earthed and I got a strange look. When I said grounded' the electrician looked happier and then knew what to do. I had a colleague who was monitoring the installation of equipment at an automotive assembly plant near Toronto. My colleague was asked about the earth connection and had to explain that it meant grounding. The first case was confusion over verbal instructions and the second was in regards to written instructions. This hasn't happened to me often, but it has happened. I rather stick with the term Earth and be done with it. I just seem to keep running into knuckle draggers who are given tasks beyond their comprehension. Ted Eckert American Power Conversion/MGE http://www.apc.com/ The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC-MGE or Schneider Electric. The speaker does not represent APC-MGE's or Schneider Electric's official position on any matter. Tarver, Peter peter.tarver@san mina-sci.com To Sent by: emc-p...@ieee.org emc-p...@ieee.org cc Subject 02/29/2008 03:50 RE: Protective Earthing PM From: Ted Eckert Sent: Friday, February 29, 2008 12:45 PM However, I have worked with electrical contractors who's staff only knows the term Grounded. Can you offer a context for this, Ted? For instance, you told the contractor's staff, be certain to earth that box. Or were they reading a manual? Regards, Peter L. Tarver, PE ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas
RE: Protective Earthing
From: Ted Eckert Sent: Friday, February 29, 2008 12:45 PM However, I have worked with electrical contractors who's staff only knows the term Grounded. Can you offer a context for this, Ted? For instance, you told the contractor's staff, be certain to earth that box. Or were they reading a manual? Regards, Peter L. Tarver, PE ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Protective Earthing
From: John Woodgate Sent: Friday, February 29, 2008 1:10 PM To: emc-p...@ieee.org Subject: Re: Protective Earthing Tarver, Peter writes: I'm not aware of anyone in the US or Canada who would misunderstand this term, if were not called 'ground.' Very likely, but 'ground' is also used all over the world by technicians whose first language is not English but who learned technical terms from American books. They are the ones who may well be confused by 'earth'. Well, then, by all means, those who insisted that 'earth' be used, instead of 'ground,' in the writing of all these IEC safety standards, needs to get in step with the rest of the world, instead of trying to make the world conform to their terminology. =8O I doubt that this will really be a problem. Manuals typically include photos or drawings or stick figures with arrows to indicate motion that make context clear enough. Those that don't read the manuals, as suggested may occur, won't have the conflict in any case. Regards, Peter L. Tarver, PE ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing
In message 5f5a140eb5cb094bb4d2c477c8c4ad99aa9...@sjc1amfpew04.am.sanm.corp, dated Fri, 29 Feb 2008, Tarver, Peter peter.tar...@sanmina-sci.com writes: If the product is deployed internationally, protective earth should be used. I'm not aware of anyone in the US or Canada who would misunderstand this term, if were not called 'ground.' Very likely, but 'ground' is also used all over the world by technicians whose first language is not English but who learned technical terms from American books. They are the ones who may well be confused by 'earth'. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Protective Earthing
I can combine the automotive reference and the reference to people who shouldn't be in the industry based on their lack of knowledge. At one time I worked for a company where one of our electrical technician was using our arc welder to fix a loose heat shield over his car's catalytic converter. Our lab manager told the technician to make sure he was on a good ground for the welding. The technician, who was lying under the car at the time, responded I am lying on the ground; how much closer can I get. Back on topic, I can state that American's understanding of Earth vs. Ground depends on their background. In my office, everybody is going to know what Earthed means. However, I have worked with electrical contractors who's staff only knows the term Grounded. The terminology used may need to be tailored to the intended audience in the United States. On the other hand, if the person doesn't know the meaning of Earthed, they probably are not the type who is going to read the manual anyway. Ted Eckert American Power Conversion/MGE http://www.apc.com/ The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC-MGE or Schneider Electric. The speaker does not represent APC-MGE's or Schneider Electric's official position on any matter. Tarver, Peter peter.tarver@san mina-sci.com To Sent by: emc-p...@ieee.org emc-p...@ieee.org cc Subject 02/29/2008 02:16 RE: Protective Earthing PM From: John Merrill Sent: Friday, February 29, 2008 8:44 AM I have a case where some want to substitute the word Ground for Protective Earth in product manuals. The products are marked with IEC 5019a protective Earthing symbol and I have no trouble proving the requirements for that. It's in the manual where references to Wire Size of Protective Earthing conductor etc that some here want to change this to Ground. From the IEV 60050-195 the term ground is a Local US term and the manual has worldwide distribution in four languages. This is almost a nonissue, regardless of any alleged confusion for a circuit reference, which seems very unlikely to occur. If the product is deployed internationally, protective earth should be used. I'm not aware of anyone in the US or Canada who would misunderstand this term, if were not called 'ground.' If they do exist, they probably shouldn't be working on the equipment in the first place. If we're going to rely on the NEC and CEC, these refer to this as the equipment grounding conductor, to differentiate it from the grounded supply conductor (neutral), rather than just as 'ground.' OT Tidbit: The first place I encountered the term 'earth' in an electrical context, was related to an automobile (an 1970 MG B), in describing the chassis circuit reference as negatively earthed. The car didn't have a drag chain and used the traditional nonconductive tires (oops, 'tyres'), so I expect there was no such thing as a 'earthed' part on the whole thing. Regards, Peter L. Tarver, PE ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message
RE: Protective Earthing
From: John Merrill Sent: Friday, February 29, 2008 8:44 AM I have a case where some want to substitute the word Ground for Protective Earth in product manuals. The products are marked with IEC 5019a protective Earthing symbol and I have no trouble proving the requirements for that. It's in the manual where references to Wire Size of Protective Earthing conductor etc that some here want to change this to Ground. From the IEV 60050-195 the term ground is a Local US term and the manual has worldwide distribution in four languages. This is almost a nonissue, regardless of any alleged confusion for a circuit reference, which seems very unlikely to occur. If the product is deployed internationally, protective earth should be used. I'm not aware of anyone in the US or Canada who would misunderstand this term, if were not called 'ground.' If they do exist, they probably shouldn't be working on the equipment in the first place. If we're going to rely on the NEC and CEC, these refer to this as the equipment grounding conductor, to differentiate it from the grounded supply conductor (neutral), rather than just as 'ground.' OT Tidbit: The first place I encountered the term 'earth' in an electrical context, was related to an automobile (an 1970 MG B), in describing the chassis circuit reference as negatively earthed. The car didn't have a drag chain and used the traditional nonconductive tires (oops, 'tyres'), so I expect there was no such thing as a 'earthed' part on the whole thing. Regards, Peter L. Tarver, PE ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing
In message of3aadd483.b7c7dc50-on862573fe.00672874-862573fe.00682...@apcc.com, dated Fri, 29 Feb 2008, ted.eck...@apcc.com writes: Have you considered defining Ground or Earth in your manual so that the English language readers clearly understand to what you are referencing? That's OK for experts, but not for the junior technicians who can't read English very well. 'Earth/ground' works for them. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing
I agree with John Woodgate that you may be best off using dual nomenclature. NFPA 70, the National Electrical Code, uses Ground and not Earth. The Canadian Electrical Code is the same. Neither defines Earth and both use it to refer to the dirt and rock beneath a structure, not an equipotential reference normally connected to the earth. I can also look at IEC 60950-1. Clause 1.2.13.10 defines Protective Earthing Conductor, but there is also a note for this clause which states In some countries, the term 'grounding conductor' is used instead of 'protective earthing conductor'. This note is not universal in IEC standards as I can not find the word ground anywhere in IEC 60335. Have you considered defining Ground or Earth in your manual so that the English language readers clearly understand to what you are referencing? The NEC defines Ground as A conducting connection, whether intentional or accidental, between an electrical circuit or equipment and the earth or to some conducting body that serves in place of the earth. This may be the place to start for a definition. Ted Eckert American Power Conversion/MGE http://www.apc.com/ The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC-MGE or Schneider Electric. The speaker does not represent APC-MGE's or Schneider Electric's official position on any matter. John Woodgate jmw@jmwa.demon.c o.uk To Sent by: emc-p...@ieee.org emc-p...@ieee.org cc Subject 02/29/2008 11:09 Re: Protective Earthing AM In message OF991E870B.BC390323-ON852573FE.005AED36-852573FE.005BEAFD@US.Schneider-E lectric.com, dated Fri, 29 Feb 2008, john.merr...@us.schneider-electric.com writes: I have a case where some want to substitute the word Ground for Protective Earth in product manuals. The products are marked with IEC 5019a protective Earthing symbol and I have no trouble proving the requirements for that. It's in the manual where references to Wire Size of Protective Earthing conductor etc that some here want to change this to Ground. From the IEV 60050-195 the term ground is a Local US term and the manual has worldwide distribution in four languages. Any suggestions on where to find good arguments against doing this? The best argument is that it is not 'either ...or...'. Only the English language is affected: I don't think there are similar variants in other languages. So the simplest solution is to print 'earth/ground' wherever necessary. Some people whose first language is not English have learned 'earth' and others have learned 'ground'. Since you have only four languages, there will be such people reading the English. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail
Re: Protective Earthing
In message OF991E870B.BC390323-ON852573FE.005AED36-852573FE.005BEAFD@US.Schneider-E lectric.com, dated Fri, 29 Feb 2008, john.merr...@us.schneider-electric.com writes: I have a case where some want to substitute the word Ground for Protective Earth in product manuals. The products are marked with IEC 5019a protective Earthing symbol and I have no trouble proving the requirements for that. It's in the manual where references to Wire Size of Protective Earthing conductor etc that some here want to change this to Ground. From the IEV 60050-195 the term ground is a Local US term and the manual has worldwide distribution in four languages. Any suggestions on where to find good arguments against doing this? The best argument is that it is not 'either ...or...'. Only the English language is affected: I don't think there are similar variants in other languages. So the simplest solution is to print 'earth/ground' wherever necessary. Some people whose first language is not English have learned 'earth' and others have learned 'ground'. Since you have only four languages, there will be such people reading the English. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Protective Earthing
You mean an argument other than the danger of confusion between the US use of ground to refer to logic reference and signal return versus protective earth? From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of john.merr...@us.schneider-electric.com Sent: Friday, February 29, 2008 10:44 AM To: emc-p...@ieee.org Subject: Protective Earthing I have a case where some want to substitute the word Ground for Protective Earth in product manuals. The products are marked with IEC 5019a protective Earthing symbol and I have no trouble proving the requirements for that. It's in the manual where references to Wire Size of Protective Earthing conductor etc that some here want to change this to Ground. From the IEV 60050-195 the term ground is a Local US term and the manual has worldwide distribution in four languages. Any suggestions on where to find good arguments against doing this? Thanks in advance. John Merrill Product Safety Engineer Schneider Automation inc. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: protective earthing test
That would be my interpretation, yes, but you'd better ask CSA just to be sure! Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Any opinions expressed are those of my invisible friend. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. From: P. Peruzzi [mailto:standa...@elen.it] Sent: Friday, April 01, 2005 12:30 AM To: Jim Eichner; emc-p...@ieee.org Subject: RE: protective earthing test Jim, thank you for your clarification. Regarding the applicability of C22.2 No 04, I've found that it was in the list of reference publications of C22.2 No 601-1 1990 edition, but it has been deleted from the list in the latest edition. Does it mean C22.2 No 04 is no longer applicable to medical devices? Paolo Peruzzi El.En. S.p.A. Via Baldanzese, 17 50041 Calenzano (FI) Italy Tel. +39 055 8826807 FAX +39 055 8832884 http://www.elengroup.com/ From: Jim Eichner jim.eich...@xantrex.com To: P. Peruzzi standa...@elen.it, emc-p...@ieee.org Sent: Thu, 31 Mar 2005 14:24:09 -0800 Subject: RE: protective earthing test The CSA approach is that you base the test current on the branch circuit overcurrent protection ahead of the product when installed as intended because the available current will determine the heating of the grounding and bonding path. In general, the breaker rating is multiplied by 2 and the test is run for 2 minutes, because the CSA and UL standards for fuses and breakers will allow anything up to 2 minutes for a breaker to trip at 200% of it's rated current. For cord-connected products, it's 2 times the plug rating but not less than 40A because a 15A plug fits into the 15/20A T-slot receptacles and may therefore be protected by a 20A breaker. For permanently connected products it's 2 times the breaker rating for 2 minutes with a ceiling of 500A for breakers of 250A or more. You'll need to get CSA C22.2 No. 0.4-04 (ie 2004 version) for the latest requirements and details. However you'll need to discuss with CSA whether or not CSA 601.1 over-rules CSA 0.4 on this topic, or perhaps the product needs to meet both. Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Any opinions expressed are those of my invisible friend. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. -Original Message- From: owner-emc-p...@listserv.ieee.org [mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of P. Peruzzi Sent: Thursday, March 31, 2005 1:03 AM To: emc-p...@ieee.org Subject: protective earthing test Dear group, Regarding medical devices, I knew protective earthing test was performed differently between EN 60601-1 and CAN/CSA 22.2 No.601-1. In particular, I read some articles talking of a 30 Amps, 2 minutes test, instead of 25 Amps, 5 seconds. Now, I've got CAN/CSA 22.2 N0 601-1, both 1990 and reaffirmed 2001 editions, and I can't find any deviation from IEC test. Could anybody help me to shed light on the matter? - Paolo Peruzzi El.En. S.p.A. Via Baldanzese, 17 50041 Calenzano (FI) Italy Tel. +39 055 8826807 FAX +39 055 8832884 http://www.elengroup.com/ This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwellmcantw...@ieee.org 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://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org
RE: protective earthing test
The CSA approach is that you base the test current on the branch circuit overcurrent protection ahead of the product when installed as intended because the available current will determine the heating of the grounding and bonding path. In general, the breaker rating is multiplied by 2 and the test is run for 2 minutes, because the CSA and UL standards for fuses and breakers will allow anything up to 2 minutes for a breaker to trip at 200% of it's rated current. For cord-connected products, it's 2 times the plug rating but not less than 40A because a 15A plug fits into the 15/20A T-slot receptacles and may therefore be protected by a 20A breaker. For permanently connected products it's 2 times the breaker rating for 2 minutes with a ceiling of 500A for breakers of 250A or more. You'll need to get CSA C22.2 No. 0.4-04 (ie 2004 version) for the latest requirements and details. However you'll need to discuss with CSA whether or not CSA 601.1 over-rules CSA 0.4 on this topic, or perhaps the product needs to meet both. Jim Eichner, P.Eng. Compliance Engineering Manager Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Any opinions expressed are those of my invisible friend. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. From: owner-emc-p...@listserv.ieee.org [mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of P. Peruzzi Sent: Thursday, March 31, 2005 1:03 AM To: emc-p...@ieee.org Subject: protective earthing test Dear group, Regarding medical devices, I knew protective earthing test was performed differently between EN 60601-1 and CAN/CSA 22.2 No.601-1. In particular, I read some articles talking of a 30 Amps, 2 minutes test, instead of 25 Amps, 5 seconds. Now, I've got CAN/CSA 22.2 N0 601-1, both 1990 and reaffirmed 2001 editions, and I can't find any deviation from IEC test. Could anybody help me to shed light on the matter? Paolo Peruzzi El.En. S.p.A. Via Baldanzese, 17 50041 Calenzano (FI) Italy Tel. +39 055 8826807 FAX +39 055 8832884 http://www.elengroup.com/ This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwellmcantw...@ieee.org 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://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwellmcantw...@ieee.org 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://www.ieeecommunities.org/emc-pstc
RE: protective earthing test
Look at the CEC and C22.2 No. 0.4 luck, Brian -Original Message- From: owner-emc-p...@listserv.ieee.org [mailto:owner-emc-p...@listserv.ieee.org]On Behalf Of P. Peruzzi Sent: Thursday, March 31, 2005 1:03 AM To: emc-p...@ieee.org Subject: protective earthing test Dear group, Regarding medical devices, I knew protective earthing test was performed differently between EN 60601-1 and CAN/CSA 22.2 No.601-1. In particular, I read some articles talking of a 30 Amps, 2 minutes test, instead of 25 Amps, 5 seconds. Now, I've got CAN/CSA 22.2 N0 601-1, both 1990 and reaffirmed 2001 editions, and I can't find any deviation from IEC test. Could anybody help me to shed light on the matter? - Paolo Peruzzi El.En. S.p.A. Via Baldanzese, 17 50041 Calenzano (FI) Italy Tel. +39 055 8826807 FAX +39 055 8832884 http://www.elengroup.com/ This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwellmcantw...@ieee.org 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://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwellmcantw...@ieee.org 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://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing Terminal Marking
I read in !emc-pstc that Peter L. Tarver peter.tar...@sanmina-sci.com wrote (in nebbkemlgllmjofmopleiedfffaa.peter.tar...@sanmina-sci.com) about 'Protective Earthing Terminal Marking' on Mon, 12 Apr 2004: I've brought this to the attention of a member of TC108 (others subscribe to this list). His comment was, I don't like it. Still, TC108 membership should be cognizant of this and consider it in their deliberations. TC108 needs some discussions with SC23G, responsible for IEC 60320, on the subject. But there appears to be a further problem. Filtered appliance couplers are said by manufacturers to conform either to IEC 60320 or IEC 60950. Neither standard actually covers *filtered* appliance couplers. These appear to come under IEC 60939-1, which is the responsibility of TC40. That implies that a 3-way liaison is required. These inter-committee liaisons often don't work well, and I think they should be carried out by: 1. Kidnapping the nominated experts to ensure that they actually attend the liaison meeting. (;-) 2. Locking them into the committee room until they have reached agreement. (;-) -- Regards, John Woodgate, OOO - Own Opinions Only. The good news is that nothing is compulsory. The bad news is that everything is prohibited. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.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://www.ieeecommunities.org/emc-pstc
Re: Protective Earthing Terminal
Martin Hi! Competitor's product is Class I. From: Martin Ansdell@MITEL on 03/19/99 09:20 AM Hello, This is the first time that I've replied to TREG, so I hope all goes well. UL requires two levels of protection. Class I equipment uses protective earth as one level, so the protective earthing terminal has to be permanent and hence the stud on the chasis method. Class II equipment satisfies two levels of protection without reliance on protective earth. Earth is only present for operational requirements. Could you confirm whether your competitor's equipment is Class I or Class II. The class makes a significant difference in the earthing requirements. Regards, Martin. From: pe...@itl.co.il on 03/18/99 11:47 PM ZE2 Please respond to t...@world.std.com To: emc-p...@majordomo.ieee.org, t...@world.std.com cc:(bcc: Martin Ansdell/Kan/Mitel) Subject: Protective Earthing Terminal 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).
Fw: Re: Protective Earthing Terminal
Posted for non-member: From: colin_mcgeec...@hp-unitedkingdom-om4.om.hp.com Subject: Re: Protective Earthing Terminal Date: Fri, 19 Mar 1999 08:54:17 + To: pe...@itl.co.il Cc: emc-p...@majordomo.ieee.org, t...@world.std.com Peter, You asked: Question 1: Can we rely on the two screws securing the appliance inlet as a means for bonding? Not for 3-wire, Class I products! As you have said the safety agencies don't like it. I expect this cannot be relied upun as these parts may be replaced in the field if they are found to be faulty. The replacement may be similar, but we cannot control that it will be an approved part if replaced by the end user themselves and necessarily have adequate grounding. Over the years, I have been told by various safety agencies that such construction is unacceptable. Question 2: Am I correct in assuming that the appliance earthing terminal for the above Listed/Certified products was considered as the main protective earthing terminal? This is true for the 3-wire, Class I product. Question 3: Why do most other ITE manufacturers use the stud on the chassis method for protective earthing terminal? To get past the agencies. Cheers, Colin. ---End of Original Message- -- Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: emc-pstc@listserv.ieee.org Date: 03/19/1999 Time: 07:37:47 -- - 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: Protective Earthing Terminal
pe...@itl.co.il writes: Dear All, Question 1: Can we rely on the two screws securing the appliance inlet as a means for bonding? Over the years, I have been told by various safety agencies that such construction is unacceptable. Over the years I, too, have been told that the metal part provided as part of the appliance inlet was not acceptable and that I would have to make a specific ground to a specific attachment point, i.e. the stud. The only explanation I recall is that the screws holding the appliance inlet may loosen (or be loosened) thus inadvertently losing the ground connection, whereas if the earth terminal is taken to a specific point where it is the first or only connection, then you must take a specific and intentional action to disconnect earth from the equipment. And, that first point of earth ground is protected with lockwashers and its own nut. Other grounds may be stacked on top of that, but it must have its own means of securement. Question 2: Am I correct in assuming that the appliance earthing terminal for the above Listed/Certified products was considered as the main protective earthing terminal? Yes. Question 3: Why do most other ITE manufacturers use the stud on the chassis method for protective earthing terminal? See my answer to #1. It was easier to give them a stud and not argue about it. It carries onward to this day. In retrospect, I don't mind it actually. It makes it clear that there is a specific point of earth ground in a system. PETER S. MERGUERIAN Regards, Scott s_doug...@ecrm.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).
Re: Protective Earthing Terminal
Peter, You asked: Question 1: Can we rely on the two screws securing the appliance inlet as a means for bonding? Not for 3-wire, Class I products! As you have said the safety agencies don't like it. I expect this cannot be relied upun as these parts may be replaced in the field if they are found to be faulty. The replacement may be similar, but we cannot control that it will be an approved part if replaced by the end user themselves and necessarily have adequate grounding. Over the years, I have been told by various safety agencies that such construction is unacceptable. Question 2: Am I correct in assuming that the appliance earthing terminal for the above Listed/Certified products was considered as the main protective earthing terminal? This is true for the 3-wire, Class I product. Question 3: Why do most other ITE manufacturers use the stud on the chassis method for protective earthing terminal? To get past the agencies. Cheers, Colin.