The protective earth conductor should be considered associated with the source of power for which the protection is needed. For example in a rack or other assembly of products you may have more than one power cord and the need is to provide earthing for the metal surfaces likely to encounter faults to the source of power associated with that earth. It is less important within products but in building wiring it is important for the neutral and earth conductors to be closely associated (run with) with the other power conductors to minimize impedances, particularly inductive barriers like going through separate holes in steel enclosures, which would interfere with overcurrent operation during faults. Products may have protective earths associated with other power sources, for example leakage from multiple telephone lines, as mentioned in IEC 60950 Cl 6.1.2.2.
Bob Johnson ITE Safety <http://www.itesafety.com> American Idle wrote: What if you have two or more power cords (redundant power supplies, for example)? Then I would think that you can say you have multiple protective conductors, even if only one is required/used. On Thu, Nov 12, 2009 at 2:36 PM, Richard Nute <[email protected]> wrote: Hi Doug: Your equipment has only ONE protective conductor (in the power cord). That one conductor connects the equipment to the external earth. Within your equipment, the point of origin to which the protective conductor in the power cord is connected is the PROTECTIVE CONDUCTOR TERMINAL. Since there is only one protective conductor in the power cord, there can be only one PROTECTIVE CONDUCTOR TERMINAL. Internally, you may connect one or more PROTECTIVE BONDING CONDUCTORS (used to internally connect other parts to earth) to the PROTECTIVE CONDUCTOR TERMINAL. There are some constructional rules for doing this. Best regards, Rich ----- Original Message ----- From: "Doug Kramer" <[email protected]> To: <[email protected]> Sent: Thursday, November 12, 2009 9:58 AM Subject: Protective Conductor Question In IEC 61010-1:2001 paragraph 6.5.1.2 b) it states "The integral protective conductor connection of an appliance inlet shall be regarded as the PROTECTIVE CONDUCTOR TERMINAL". Are there any cases where the protective conductor connection can be elsewhere when an IEC appliance inlet with ground is used? Can there be more than one protective conductor terminal? Thanks, Doug Kramer - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]>
