Main Bonding Jumper for Service

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jazer

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Gibsonia, Pa
I am doing some unrelated work on a home when I noticed in the service troff that a critical connection may be missing. I am having a hard time finding the correct code section to clarify. The troff has the main service conductors off of the meter, they are 250kcm alum. off of the troff is a 150 amp disco and a 150 amp main panel. The GEC is a 4 copper run to the troff, a #4 bonded to the troff, a #6 to the rods, and a #6 to each the disco and main panel all under one split bolt, but no connection to the neutral. My concern is that though the two "mains" are bonded appropriately, shouldnt the #4 GEC be bonded to the neutral in the troff as well? Please let me know if more description is necessary. Thanks.
 
IMO, if I underdtand correctly the #6's from the service panel is bonding the wireway. (depending on the fittings used it might be bonded by the conduits also).
There woudl be a violation with the multiple conductors under one split bolt,
 
the wireway is bonded with a #4 jumper to the GEC, however, if there a was a ground fault in the wireway, current would flow thru the #4 jumper, then thru the #6 to the neutral 2/0 in either the 150 amp main panel or the 150 amp disco. Yikes! Too small for the 250 kcm! And you are correct about the split bolt, that I will be changing to a terminal block.
 
You are correct, my old eyes fooled me. A 250kcmil AL requires a #4 Cu bonding jumper. That said, I would not be overly concerned as you have two #6s bonding the wireway,
( I re-read your OP.. are the neutrals bonded to the cans in your service disconnects ? )
 
Yes, they are bonded in the main panel and the disco. Good point on the parallel #6's. However, I cannot find this clarification in the code. I know there is verbage about bonding at the point where the GEC is brought to at the service....???
 
Yes, that is what I was searching for. I feel better. I didnt want to have to pull apart the neutral tap in the troff. Thank you much!!
 
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