RE: Earthing through screws.
adding to a long screw with additional nuts and wires is OK, as long as the first lug/wire is tied to chassis with its dedicated nut, then more can be added, as long as the first is not disturbed.. Richard, -Original Message- From: Gary McInturff [mailto:gary.mcintu...@worldwidepackets.com] Sent: Tuesday, September 17, 2002 11:02 AM To: Chris Maxwell; David Sproul; Doug McKean Cc: EMC-PSTC Subject: RE: Earthing through screws. The primary screw has the ground symbol (upside down Christmas tree) in a circle, all other locations you want to indicate as ground, called PROTECTIVE BONDING SCREWS by the standard can use the symbol but without the circle, but it is not required to mark them. At least that's the word from UL 60950 section 1.7.7.1. Heck the screws that bond the cover to the base and its connection to the primary earthing connector are examples of this type of bonding. If you had two separate chassis with signal and other non-primary power interconnects, you might pass bonding through a braid strap or something as well. Reaching here, because I can't think of a time I didn't cram everything into a single enclosure. Gary -Original Message- From: Chris Maxwell [mailto:chris.maxw...@nettest.com] Sent: Tuesday, September 17, 2002 4:08 AM To: David Sproul; Doug McKean Cc: EMC-PSTC Subject: RE: Earthing through screws. David, Your question isn't so stupid as you say. It is correct that the primary grounding screw (the first screw connected to the ground wire from the AC inlet) shouldn't be used for any purpose other than grounding. However, the standards do allow that screws and fasteners can be used to pass this grounding on to other parts of the chassis. In that context (I guess you could call them secondary ground screws), your question is valid. It is worthwhile considering labeling these screws with a ground label; especially if a user could remove this screw and still operate the product. I guess what I'm trying to say is: your specific question may have an obvious answer; but the fact that you were thinking about how to make the product safe is just as important as quoting any standard chapter and verse. It is never stupid to use logic and reason along with the standards. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | A friend is a person who knows the song in your heart because they stopped singing their own song long enough to hear yours :-) -Original Message- From: David Sproul [SMTP:david.spr...@alexanderlynn.co.uk] Sent: Monday, September 16, 2002 5:46 PM To: Doug McKean Cc: EMC-PSTC Subject: RE: Earthing through screws. Hello Doug, I believe you are right. If I had taken the trouble to read EN60950 para 2.6.5.7, I would have saved my self from asking stupid questions. Thanks also to all those who responded to my orignial posting. regards, David Sproul. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list
Re: Earthing through screws.
[ John Woodgate wrote ] Oh, come on! There are dozens of safety standards; surely you don't expect me to search and list them all? [ Doug McKean wrote ] You can't possibly be serious. I was more interested in the fact that since this forum is basically ITE, Medical, Test, and SEMI that at least some brief mention of at least one or maybe even two standards of which you're aware without research would suffice. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Earthing through screws.
The primary screw has the ground symbol (upside down Christmas tree) in a circle, all other locations you want to indicate as ground, called PROTECTIVE BONDING SCREWS by the standard can use the symbol but without the circle, but it is not required to mark them. At least that's the word from UL 60950 section 1.7.7.1. Heck the screws that bond the cover to the base and its connection to the primary earthing connector are examples of this type of bonding. If you had two separate chassis with signal and other non-primary power interconnects, you might pass bonding through a braid strap or something as well. Reaching here, because I can't think of a time I didn't cram everything into a single enclosure. Gary -Original Message- From: Chris Maxwell [mailto:chris.maxw...@nettest.com] Sent: Tuesday, September 17, 2002 4:08 AM To: David Sproul; Doug McKean Cc: EMC-PSTC Subject: RE: Earthing through screws. David, Your question isn't so stupid as you say. It is correct that the primary grounding screw (the first screw connected to the ground wire from the AC inlet) shouldn't be used for any purpose other than grounding. However, the standards do allow that screws and fasteners can be used to pass this grounding on to other parts of the chassis. In that context (I guess you could call them secondary ground screws), your question is valid. It is worthwhile considering labeling these screws with a ground label; especially if a user could remove this screw and still operate the product. I guess what I'm trying to say is: your specific question may have an obvious answer; but the fact that you were thinking about how to make the product safe is just as important as quoting any standard chapter and verse. It is never stupid to use logic and reason along with the standards. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | A friend is a person who knows the song in your heart because they stopped singing their own song long enough to hear yours :-) -Original Message- From: David Sproul [SMTP:david.spr...@alexanderlynn.co.uk] Sent: Monday, September 16, 2002 5:46 PM To: Doug McKean Cc: EMC-PSTC Subject: RE: Earthing through screws. Hello Doug, I believe you are right. If I had taken the trouble to read EN60950 para 2.6.5.7, I would have saved my self from asking stupid questions. Thanks also to all those who responded to my orignial posting. regards, David Sproul. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Earthing through screws.
David, Your question isn't so stupid as you say. It is correct that the primary grounding screw (the first screw connected to the ground wire from the AC inlet) shouldn't be used for any purpose other than grounding. However, the standards do allow that screws and fasteners can be used to pass this grounding on to other parts of the chassis. In that context (I guess you could call them secondary ground screws), your question is valid. It is worthwhile considering labeling these screws with a ground label; especially if a user could remove this screw and still operate the product. I guess what I'm trying to say is: your specific question may have an obvious answer; but the fact that you were thinking about how to make the product safe is just as important as quoting any standard chapter and verse. It is never stupid to use logic and reason along with the standards. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | A friend is a person who knows the song in your heart because they stopped singing their own song long enough to hear yours :-) -Original Message- From: David Sproul [SMTP:david.spr...@alexanderlynn.co.uk] Sent: Monday, September 16, 2002 5:46 PM To: Doug McKean Cc: EMC-PSTC Subject: RE: Earthing through screws. Hello Doug, I believe you are right. If I had taken the trouble to read EN60950 para 2.6.5.7, I would have saved my self from asking stupid questions. Thanks also to all those who responded to my orignial posting. regards, David Sproul. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Earthing through screws.
I read in !emc-pstc that Doug McKean dmck...@corp.auspex.com wrote (in 006101c25dec$2b8d49e0$cb3e3...@corp.auspex.com) about 'Earthing through screws.' on Mon, 16 Sep 2002: [ Doug McKean wrote ] I wasn't aware that primary grounding securements could be used for another purpose. [ John Woodgate wrote ] It depends on the applicable safety standard; some allow it, some don't. [ Doug McKean wrote ] Then since you've got my curiosity up, which ones allow for primary grounding securement to be used for something other than primary grounding. Oh, come on! There are dozens of safety standards; surely you don't expect me to search and list them all? -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Earthing through screws.
[ Doug McKean wrote ] I wasn't aware that primary grounding securements could be used for another purpose. [ John Woodgate wrote ] It depends on the applicable safety standard; some allow it, some don't. [ Doug McKean wrote ] Then since you've got my curiosity up, which ones allow for primary grounding securement to be used for something other than primary grounding. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Earthing through screws.
Hello Doug, I believe you are right. If I had taken the trouble to read EN60950 para 2.6.5.7, I would have saved my self from asking stupid questions. Thanks also to all those who responded to my orignial posting. regards, David Sproul. -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Doug McKean Sent: 16 September 2002 18:58 To: EMC-PSTC Subject: Re: Earthing through screws. I wasn't aware that primary grounding securements could be used for another purpose. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Earthing through screws.
I read in !emc-pstc that Doug McKean dmck...@corp.auspex.com wrote (in 003e01c25daa$8da4b380$cb3e3...@corp.auspex.com) about 'Earthing through screws.' on Mon, 16 Sep 2002: I wasn't aware that primary grounding securements could be used for another purpose. It depends on the applicable safety standard; some allow it, some don't. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Earthing through screws.
I wasn't aware that primary grounding securements could be used for another purpose. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Earthing through screws.
Dear group, Could someone please remind me of the marking requirements for screws used for safety earthing purposes. The screws in question are also used to secure a small drawer into a grounded metal rack. Would it be sufficient to include a warning in the installation manual that the screws are also required for earthing purposes, or would they have to be visibly identified as part of the safety earthing? Your comment would be gratefully received. Best regards, David Sproul,
