Posted by Mark Kw
on April 6, 2010, 6:55:22, in reply to "Re: your question"
71.48.250.25
Lightning does some interesting things. Sorry to hear about the fire, I hope it wasn't bad.
The coax likely survived because as I understand it, the bulk of the current doesn't flow through the conductor but around it. My first training was from a PA utility and later a private company selling somewhat sensitive equipment. Most all the bonding was done using flat braided straps made from extremely fine strand Cu and insanely expensive. In lieu of the flat braided straps, certain applications allowed for the use running parallels of diesel/weld cable.
Like I said, when I saw those pic's, Wolf's work threw me for a loop because it went against everything I was taught on the commercial side so I retract slamming him because I'm no expert, just going off what I was taught. The inspectors I dealt with (I went to the same classes with many of them) would have taken one look at that and had a conniption fit. We had to run all the lightning ground paths on arc-breaking standoffs even over a conductive surface like a steel roof/bulkhead. Minimum of 36" air gap to any utility conductor run, exceptions were point of entrance, equipment connections or other points of termination. Generally no one was too picky about the exact radius of bends as long as it was a long-sweep bend (IIRC the minimum radius was supposed to be 36").
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