One utility feed, one generator, two buildings

Status
Not open for further replies.
B

BigMike

Member
Saw a few topics that are close to mine, but not exactly. I'm throwing this out there for the experts here to help me!

I have one utility feed. The main switchboard is in Building A. There is a circuit breaker in the switchboard of A that feeds a panelboard in Building B. I am not carrying a ground wire in this circuit because the ground will be established at Building B's outside disconnect in accordance with 250.32 where the ground and neutral will be bonded together.

There is an emergency generator that feeds an ATS in Building A. On the load side of the ATS is an emergency distribution panel. This panel feeds 5 panels in Building A and one panel in Building B.

So where does the emergency panel Building B get its ground from? Do I connect to the ground in the service disconnect of Bldg. B just like the normal panel? Or is an ATS in Bldg. B the way to go?

Many thanks,
Mike
 
I'm not sure I understand the design Mike. If the one panel in bldg B is fed from the ATS in bldg A then it has nothing to do with the Main Disco at bldg B.

IMO this feeder from the ATS should be run with an EGC to a disco grouped with bldg B's main then to the PNL.

Or you can wait for these guys.

Big Mike said:
I'm throwing this out there for the experts here to help me!
Click to expand...
 
If I was doing this job, I would pull 4 wires from the main panel to the "B" building, and I would pull another 4 wires from the ATS to the "B" building... This would be allowed by 225.30 (A) (4)

At building "B" you would install your seperate building or structure grounding electrode required by 250.32 (a)


What you propose in your opening post would be a code violation of 250.32 (B)(2)
 
Last edited:
Status
Not open for further replies.
Top