Hello all....I am getting ready to replace the 60 year old wiring thatgoes from my house to my detached garage. I recently had the houseservice upgraded from a 60 amp fuse service to a 200 amp circuit panel,and now want to replace the old wiring going to the garage. Theexisting wiring goes through an underground conduit from my cellar tothe garage. I plan on having a compressor and eventually a welder(automotive stuff...nothing too fancy), and nothing much else outthere. My question is; what guage or type of wire should I run outthere? I am planning on installing all the breaker panel, but notmaking the final connections...I'm new at this stuff.Any help would be greatly appreciated.

The size and amps of the welder will determine what you need. That is a big draw.No welder and for a 50 foot run or less I would think 10/3 wg and a 4 breaker subpanel would be all you needed. That would give you one 220 and 2 20's. Of course you could not use it all at once.Would not be surprised to see the load calculations for a welder double or treble that wire and box size.Maybe Doug will give you a better answer.Colbyt

Correct, only the main feeder(s) to the panelboard(s) qualify. If he has multiple service disconnects, and one of them fed the garage panel, it would qualify, but not if his garage feeder came off of a breaker from a panel which was on the load side of a service disconnect

What cable to use... (2026 Update)

Dec 16, 2006 Last reply: 1 month ago 25 Replies

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RBM 19 years ago

In a situation where the service disconnect is in the main service panel, there is no main feeder

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Doug Miller 19 years ago

And feeders from the main panel to subpanels don't qualify? As described in the Code, it seems that they would.

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RBM 19 years ago

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Doug Miller 19 years ago

Gotcha. "Load side of the service disconnect" seems to be the crucial part.

Thanks for the clarification.

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Tom Horne, Electrician 19 years ago

No such feeders to panels that supply only a fractional portion of the dwelling units load do not qualify. The use of the plural in the code language is intended to cover feeders to multiple dwelling units within a single structure. Each feeder must be the main feeder for the entire dwelling unit in question. The reduced conductor sizes are predicated on the diversity of loading that is inherent in the way an entire dwelling uses power. When only parts of the load are carried by a sub feeder that diversity is no longer assured.

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Tom Horne, Electrician 19 years ago

The section in question covers only dwelling units. A detached garage is not a dwelling unit. Residential outbuildings of any description that are not in fact dwelling units must be supplied with conductors sized in accordance to table 310.16.

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