Adding a subpanel to a garage !

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Old 03-14-17, 05:20 PM
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Adding a subpanel to a garage !

I want to add a subpanel in my garage. I would like to have two 220v circuits and probally two or three 110v circuits for outlets. One of the 220 circuits will be dedicated for a 80 gallon compressor. The other for a welder or whatever down the road. I would like to know what amperage subpanel I should get? What size breaker should I get to feed the subpanel? I have the wire already to feed the subpanel. Any help would be very appreciated.
 
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Old 03-14-17, 05:28 PM
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I would like to have two 220v circuits and probally two or three 110v circuits for outlets. One of the 220 circuits will be dedicated for a 80 gallon compressor.
Nominal voltage is 120v and 240v.
I have the wire already to feed the subpanel.
You have the cart before the horse. What size and kind of wire? The loads in amps you will have on at any one time determines the feed to the panel and the feed determines the wire size.

Is this an attached or detached garage?
 
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Old 03-14-17, 05:29 PM
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Welcome to the forums.

I have the wire already to feed the subpanel.
And what size is that as it dictates everything ?
 
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Old 03-14-17, 05:36 PM
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It is a attached garage and the wire has four 8 awg and one 10awg ground
 
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Old 03-14-17, 05:42 PM
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That sounds like 8-3 NM-b w/ground. #8 cable will yield 40A of power.

You would use a 2P40A breaker.
That would be rather small for a welder.
 
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Old 03-14-17, 05:56 PM
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That would be 8/4 with ground.
 
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Old 03-14-17, 06:00 PM
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The wire was given to me so I'm not out anything if it can't be used. So let's start over since I was ahead of myself. The compressor is a 230v/24A/1 phase, but can double the amps when the motor starts. Not sure on what a welder would need as far as amperage. And the other outlets I wouldn't think would exceed 20 amps.
 
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Old 03-15-17, 05:01 PM
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Ok I have a 100 amp subpanel and I would like to be able use all amperage available at one point or another. So what size feeder breaker can I install in the main panel? and what size and type of wire should I use to provide 100 amps? Routing the wire through the house to the garage would be very difficult, can I route it outside to the garage if I use conduit? That is alot shorter I would think and alot easier but I'm not sure if that's acceptable. Just looking for some advice. Thanks
 
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Old 03-15-17, 06:02 PM
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Sure you can go outside in conduit. Use a 100A breaker and use 1-1-1-3 Al SER and depending on how it's run you may not need much conduit at all, only where protection is needed. Make sure your main panel can take a 100A breaker, but most likely it can.
 
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Old 03-15-17, 08:29 PM
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SER cable cannot be used underground.
 
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Old 03-15-17, 08:37 PM
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You could use mobile home cable.
 
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Old 03-16-17, 07:04 AM
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SER cable cannot be used underground.
I know SER can't go underground and didn't say to run it underground. He can run conduit on the outside wall to garage if needed.

Pavs1029, when you say outside, are you asking about above or below ground?
 
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