Regarding the attachment of the overhead service mast to the meter/load panel, can teflon tape be used on the threads at the mast-to-flange connection? Or does this need to be electrically bonded (ie, no tape)?
I was thinking of waterproof vs. electrical bond, and couldn't decide.
Thanks.
Teflon tape will not interrupt the electrical connection, nor will pipe dope. There is plenty of metal to metal contact when you tighten that down.
This may vary by locale, but I had to install grounding bushings on the threads of the pipe within the meter box to bond the mast conduit to the meter box ground lug. Same with the metal conduit going out the bottom to the service panel.
If you have a hub to the mast, where do you put the bushing? The threads bottom in the hub. 250.92(B)(2) does say this needs to be made up wrench tight. I agree you do need bonding bushings on the raceways going through knockouts.
I have worked in areas were the utility required one of the hub screws to be long enough to accept a lug on the inside of the meter enclosure in order to bond the mast to the enclosure and the conduit to the Service Equipment.
-- Tom Horne
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