[PSES] Serrated head screws for grounding/bonding
Good morning. I am reviewing the suitability of serrated head screws in grounding and bonding applications. I am aware that these screws are good at resisting vibration, but I've not seen them used for grounding and bonding purposes. I question this application since, while the serrations oppose loosening of the screw, they do not bite into the metal beneath the head and also seem unlikely to form a gas-tight connection, allowing degradation of the grounding/bonding interface over time. What are your opinions? Are you aware of any evidence of the reliability of an grounding/bonding connection using such screws? The screw will secure a wire, possibly with a crimp-on ring connector. (I also question the value of using a single toothed washer in these applications.) Regards, Peter L. Tarver This email message is for the sole use of the intended recipient(s) and may contain confidential and/or privileged information. If you are not an intended recipient, you may not review, use, copy, disclose or distribute this message. If you received this message in error, please contact the sender by reply email and destroy all copies of the original message. - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas sdoug...@ieee.org Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Serrated head screws for grounding/bonding
Hi Peter: If the serrated head screw is suitable for a mains circuit connection, it is suitable for a PE circuit connection. The biggest problem is whether a certification house will accept the construction. Be prepared (plan B) to replace the screw with a conventional screw and lockwasher. Best regards, Rich - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas sdoug...@ieee.org Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Serrated head screws for grounding/bonding
In message 16ad10a67c6df27b6a7e5fbe13b3c...@mail.gmail.com, dated Thu, 26 Feb 2015, Peter Tarver ptar...@enphaseenergy.com writes: I question this application since, while the serrations oppose loosening of the screw, they do not bite into the metal beneath the head and also seem unlikely to form a gas-tight connection, allowing degradation of the grounding/bonding interface over time. It obviously depends on the shape of the serrations and the tightening torque. What matters is the pressure at the junctions between the tips of the serrations and the substrate. Serrations that are less than sharp can still be OK because the contact area is greater, but a higher torque may be necessary. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk When I turn my back on the sun, it's to look for a rainbow John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas sdoug...@ieee.org Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Serrated head screws for grounding/bonding
I just checked my collection of extra green bonding screws that come with the listed metal junction boxes and lighting fixtures etc. for building wiring (US). Some of them are serrated. They would be used with solid copper or ring terminals. -Dave -Original Message- From: Peter Tarver [mailto:ptar...@enphaseenergy.com] Sent: Thursday, February 26, 2015 11:39 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] Serrated head screws for grounding/bonding Good morning. I am reviewing the suitability of serrated head screws in grounding and bonding applications. I am aware that these screws are good at resisting vibration, but I've not seen them used for grounding and bonding purposes. I question this application since, while the serrations oppose loosening of the screw, they do not bite into the metal beneath the head and also seem unlikely to form a gas-tight connection, allowing degradation of the grounding/bonding interface over time. What are your opinions? Are you aware of any evidence of the reliability of an grounding/bonding connection using such screws? The screw will secure a wire, possibly with a crimp-on ring connector. (I also question the value of using a single toothed washer in these applications.) Regards, Peter L. Tarver This email message is for the sole use of the intended recipient(s) and may contain confidential and/or privileged information. If you are not an intended recipient, you may not review, use, copy, disclose or distribute this message. If you received this message in error, please contact the sender by reply email and destroy all copies of the original message. - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas sdoug...@ieee.org Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas sdoug...@ieee.org Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Serrated head screws for grounding/bonding
Peter: The military doesn’t like that method. I think the primary reason is that the serrations form small point-contact connections, and, under heavy fault current, these little points will melt and/or vaporize. The military prefers a strap which terminates in a flat ring-lug, with the lug being clamped against the physical ground structure with a heavy nut and split-ring compression washer. The washer is placed between the nut and the top face of the flat lug, never between the lug and the ground surface. The purpose of the compresion washer is to maintain pressure of the lug against the ground structure. Ed Price WB6WSN Chula Vista, CA USA Good morning. I am reviewing the suitability of serrated head screws in grounding and bonding applications. I am aware that these screws are good at resisting vibration, but I've not seen them used for grounding and bonding purposes. I question this application since, while the serrations oppose loosening of the screw, they do not bite into the metal beneath the head and also seem unlikely to form a gas-tight connection, allowing degradation of the grounding/bonding interface over time. What are your opinions? Are you aware of any evidence of the reliability of an grounding/bonding connection using such screws? The screw will secure a wire, possibly with a crimp-on ring connector. (I also question the value of using a single toothed washer in these applications.) Regards, Peter L. Tarver This email message is for the sole use of the intended recipient(s) and may contain confidential and/or privileged information. If you are not an intended recipient, you may not review, use, copy, disclose or distribute this message. If you received this message in error, please contact the sender by reply email and destroy all copies of the original message. - 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 mailto:emc-p...@ieee.org emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas mailto:sdoug...@ieee.org sdoug...@ieee.org Mike Cantwell mailto:mcantw...@ieee.org mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: mailto:j.bac...@ieee.org j.bac...@ieee.org David Heald: mailto:dhe...@gmail.com dhe...@gmail.com - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas sdoug...@ieee.org Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Preamplifiers
In message 54eedb01.9060...@earthlink.net, dated Thu, 26 Feb 2015, CR k...@earthlink.net writes: A discussion on LinkedIn, in the EMC Experts group, topic RE02 on HF radio with fixed antenna (in Tx), includes a sub-topic about an active rod antenna that sees fairly strong odd-order harmonics of a 250KHz comb generator that doesn't produce them into 50 Ohms. Significantly, a later version of the same active antenna doesn't see them. I ascribe that to overload, and the onset of noticeable IMD. It is presumably some sort of 'overload', but these effects can be subtle if it's an intermediate stage that goes non-linear at an unexpectedly low signal level. Testing with a single signal is not enough; a comb generator is likely to show up any such effect but with digital processing there are so many possibilities, some remote (but can always catch you out). -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk When I turn my back on the sun, it's to look for a rainbow John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas sdoug...@ieee.org Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Preamplifiers
On 2/25/2015 12:37 PM, John Woodgate wrote: For example, if you expect to put in impulsive noise you should ask how well the instrument copes with it. A discussion on LinkedIn, in the EMC Experts group, topic RE02 on HF radio with fixed antenna (in Tx), includes a sub-topic about an active rod antenna that sees fairly strong odd-order harmonics of a 250KHz comb generator that doesn't produce them into 50 Ohms. Significantly, a later version of the same active antenna doesn't see them. I ascribe that to overload, and the onset of noticeable IMD. Cortland Richmond - 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas sdoug...@ieee.org Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
