Ken: That "...some arcing/sparking along the way..." can be very dramatic. I wouldn't be surprised to examine such a conduit / ground path after a strike and find the bottom equipment box blown off the pole or maybe a foot or so of conduit has been vaporized and embedded in the pole.
Also, ground paths can be very long; envision a 1,500 foot high broadcast tower standing on the Nebraska plains. I wonder how many strikes the Petronas Towers endure in a year? Ed Price WB6WSN Chula Vista, CA USA From: Ken Javor [mailto:[email protected]] Sent: Wednesday, May 15, 2019 10:06 AM To: [email protected] Subject: Re: [PSES] Just curiosity If the purpose of the copper conductor is to act as a lightning rod, and ensure the lightning doesn't travel through the wood, does it matter if instead the conductor is galvanized pipe and there is some arcing/sparking along the way? Ken Javor Phone: (256) 650-5261 ________________________________ From: Edward Price <[email protected]> Reply-To: Edward Price <[email protected]> Date: Wed, 15 May 2019 10:03:55 +0000 To: <[email protected]> Conversation: Just curiosity Subject: Re: [PSES] Just curiosity Ken: If a lightning path connects to the top of that conduit, what is the path to Earth ground for that charge? There are probably several screwed joints down the pole, and then, your photo shows the conduit running into an adapter (which itself looks to be clamped to the equipment box by an internal nut). And then, how is the box grounded? All those joints would be acceptable if they were welded, but chances are that each those joints has quite a bit more resistance than a welded joint. Perhaps some of those joints only have a few points of contact to effect the electrical connection. Dumping maybe 30 kA down that path could well result in some spectacular joint arcing. I suspect that instead of going to the trouble of welding all the joints, the copper conductor provides the Earth bonding for a lot less cost. Ed Price WB6WSN Chula Vista, CA USA - ---------------------------------------------------------------- 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.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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
