Grounding CT Cabinet

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T DeNault

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New York
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Electrician
I have a 600 amp single phase 120/240 volt residential service. Utility feeders enter CT cabinet then 3 sets of 4/0 feeders feed 3 separate. 200 amp mains. My question:

Do I run a ground wire with the neutral from CT cabinet to main disconnects? ( do I run a 4 wire or a 3 wire feeder)
 
T DeNault said:
I have a 600 amp single phase 120/240 volt residential service. Utility feeders enter CT cabinet then 3 sets of 4/0 feeders feed 3 separate. 200 amp mains. My question:

Do I run a ground wire with the neutral from CT cabinet to main disconnects? ( do I run a 4 wire or a 3 wire feeder)
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You would have a SSBJ (supply side bonding jumper) which is sized differently since you are ahead of the first OCPD. Don’t know the table off the top of my head but somebody else will.
 
Dsg319 said:
You would have a SSBJ (supply side bonding jumper) which is sized differently since you are ahead of the first OCPD. Don’t know the table off the top of my head but somebody else will.
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don_resqcapt19 said:
The code permits the CT cabinet to be bonded to the neutral and does not require any additional conductors.
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I would say, For NEC purposes, you have your choice of bonding the CT can to the neutral (grounded conductor), or running SSBJ's back to the service disconnects. May want to check POCO specs too however, for example Seattle City Light says in their spec book that the CT can is not to be bonded to the neutral conductor (directly).
 
Our POCO has a nice detail drawing that shows bonding of the CT can, as opposed to Seattle City Light, we bolt a big neutral bus to the can, and land neutral there
 
Definitely contact your POCO and see how they want it. They have drawing for all different types of installations. Here's what Socal Edison Says

"

"The neutral conductor shall be continuous through the instrument-transformer cabinet and shall be
run at the rear or along the side of the cabinet. Where used as a terminating pull box, a double
neutral lug shall be provided. The neutral shall be bonded to the enclosure."
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SSDriver said:
"The neutral conductor shall be continuous through the instrument-transformer cabinet and shall be
run at the rear or along the side of the cabinet. Where used as a terminating pull box, a double
neutral lug shall be provided. The neutral shall be bonded to the enclosure."
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In my opinion, it would be much more accurate if they said. "The enclosure shall be bonded to the neutral."

After all, that's really what we're doing when we are assuring the low-impedance pathway back to the source.
 
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