Putting in a Garage Sub Panel
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Putting in a Garage Sub Panel
I want to install a sub panel in my garage. The main panel is on the outside wall and the sub panel would be directly behind it on the inside wall. In the sub panel I want a 30A 220V breaker and a 20V 110V breaker. What size breaker and what gauge wire do I need in the main panel to feed the sub panel? And is there anything specific I need to know as far as what kind of panel to buy?
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Even though those are the only two circuits you are wanting, I'd do a little future proofing and install at least a 20 space 100A main breaker panel and feed it with a 60A breaker in the main panel. If using conduit use three #6 THHN and one #10 THHN. SER cable can be used if not using conduit, that will be 6-6-6-6. In a subpanel you will need to buy a ground bar kit because the neutrals are isolated from the grounds. This requires the bonding screw/strap to be removed from the existing neutral/ground bar to isolate it from the panel box.
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NM-b is fine only if directly entering from one panel to another and not run through outside conduit or exposed to the outside since NM-b is not allowed in damp/wet areas. SER is allowed in wet areas. A piece of copper SER is better than NM-b since it is being run to the outside of the structure. This is assuming the main panel is on the outside of the structure.
#5
The main panel is on the outside wall and the sub panel would be directly behind it on the inside wall
Based on the info above it sounded to me that the cable would not be installed in a wet location.