Sub panel connection to main

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jsparks

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Ok, I read a recent post http://forums.mikeholt.com/showthread.php?t=130233&highlight=ground+wire+panel but I wanted to ask my question to clarify without bringing up the irrelevant parts of that post:

On a subpanel that is going to be connected to the main with emt, are we required to run the ground wire or will connectors wrench tight be sufficient for continuity? I am not talking about the neutral, but specifically the ground wire. I understand that neutral and ground wires are separate in subpanels with ground required to be carried back to main for termination.

Thanks in advance!
 
You need some sort of EGC run with the feeder for the subpanel. The section that Roger gave you will show what those code compliant EGC's are.
 
If over 250 volts to ground and you have concentric or eccentric KO's, or other oversized opening you may need a bonding bushing, bonding locknut, or other similar device.

See 250.97.
 
kwired said:
If over 250 volts to ground and you have concentric or eccentric KO's, or other oversized opening you may need a bonding bushing, bonding locknut, or other similar device.

See 250.97.
Click to expand...

Or just remove all the rings and use reducing washers with a lock nut. :)

Roger
 
Thanks guys. I like how 358.60 just puts it out there for you: emt = egc :grin:

The install will be for 100a sub, 120/240 a few feet away from the main in the garage of a residence.

Looks like according to 310.15b, #3 thhn under 75 deg will be ok for 100a.
The conduit satisfies ground wire req and according to annex c, 1" emt can be used for the 3 remaining wires (2 legs and neutral).

Did I misinterpret any of the codes?

Since its 120/240 service, are locknuts sufficient or would it be required to install grounding bushings?
 
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