WIring Detached Garage

btedford

I am wiring a detached garage with a 100 amp subpanel off my main 200 amp panel, I am running from the main panel 4 - 3 gauge wires. One is green insulated for ground and the other 3 are black identified as white, red and black. My plan was to run all 4 wires in 1 1/2 conduit from main panel to sub panel. I assume the ground I run from the main to the sub panel is sufficient grounding. My question is do I still need to ground the sub panel to a ground rod at the garage? If so do I just ground the can or do I ground to the grounding bar in the panel? I don't think I can sink it 8 feet because of rock. Is this an issue?

I will have a 100 amp breaker in my main panel to support the subpanel.

Thanks in advance

a7ecorsair

You will need a ground rod. You will also have to make sure the neutral bar and ground bar are separate and that there isn't a bonding screw installed in the neutral bar. The ground bar will need to be bonded to the panel case or directly mounted on the case. Check with your inspector and see if he will allow the ground rod to be laid in the trench or driven at an angle.

btedford

Thanks for the answer. If I sink a ground rod at the garage do I still need to run a ground wire from the 200 amp panel to the 100 amp panel or is the grouding rod sufficeint?

This work is being done in Newfoundland.

secutanudu

You only need a #8 ground wire for 100 amp:

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Andrew

J. V.

Are you using single wires or a cable? You mention white? Rarely do I see white sold separately at size #3. I am certain its available, but seldom would be used, as #3 can be re-identified.
If you have a cable, post what type of cable you have.

btedford

I'm using 3 gauge 7 strand black insulated for all colours. I already have the ground wire in 3 gauge green insulation.

If I ground to a separate ground rod at the garage do I still need to run a ground from the mainpanel to the subpanel in the garage?

secutanudu

What is the marking on the actual wire? Is it copper?

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Andrew

btedford

The wire is 7 strand copper.

secutanudu

Tha'ts not enough information, what does it say on the wire? THHN? THWN?

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Andrew

AllanJ

#4 or larger wires may be remarked as neutral or ground.

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