Residential 400A CT service Questions

T

T. See

Member
Location
NY
Occupation
Electrician
I'm installing a 400 A CT service for one of my better customers this week and I've never done one before. The utility here provides the cabinet, CT's, and meter. I got them yesterday. The change over is scheduled for this Thursday and has been on the books for two plus months. This service comes to a private pole where the existing 200A meter is located. The plan is to reuse the existing feeders going to the house and we've run new 2" PVC to the detached garage and pulled 4/0, 4/0, 2/0 URD to a new 200A panel.

I met with a planner from the utility (he's the one that suggested the CT service) two months ago who signed off on my plan. He's been unavailable since then.

Going over the paperwork provided with the equipment, they require that the service neutral and CT cabinet be bonded to ground in the CT cabinet. Does this ground then become the GEC?

My boss and I have been going back and forth on this one but, I would like to add two 200 A disconnects on the pedestal on the load side of the CT cabinet. But if I do this wouldn't I be required to pull a ground with my feeders, or is there a way around this?

You're help is greatly appreciated.
 
The neutral will be the ground for the CT cabinet. If allowed by POCO, you would be better off to treat the "downstream" conductors as service and place your disconnects at the structures that way no 4th wire is required.
 
The CT cabinet should be just like a meter cabinet with the neutral lugs just bolted to the chassis and not isolated. If they are isolated, it would be nice if they give you a means to bond that bar to the chassis. If there is no disconnect in that cabinet, it is still line side of service where everything is grounded by the neutral. The GEC could originate here if you have an additional neutral lug or split bolt onto the neutral.

You don't separate to 4 wires until you hit the main disconnet(s).
 
Thank you both very much. This definitely helps.

Their instructions - "CT cabinet must be bonded to service with #4 copper ground. Please include terminal block for neutrals with extra space for #10 solid copper metering wire. Neutral bar to be directly connected to enclosure"

My plan is to add a ground bar with 4/0 lugs for the neutrals and enough extra space for whatever else they might need

I've spent a few sleepless nights on this one.
 
If the utility is providing the equipment would the necessary neutral bus and grounding lugs be installed?

That ground buss is only rated to be used as a ground buss. Not a current carrying neutral buss.
 
curt swartz said:
If the utility is providing the equipment would the necessary neutral bus and grounding lugs be installed?

That ground buss is only rated to be used as a ground buss. Not a current carrying neutral buss.
Click to expand...
You would think so but that is not the case.
 
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