Old 08-29-04, 05:54 PM
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I am building a 2400 square foot shop out behind my home. I am hiring subs contrs where I must. I need help with some electrical questions. Can I use a sub panel out in the new bldg fed from heavy wires direct from the inlet of the main breaker box at the house? What are the basic things that I need to know? How big of a sub panel do I need? How heavy of wire must I use to feed the shop sub panel? The sub panel is approximately 100 feet away from the main box. Any help will be much appreciated.
Old 08-29-04, 06:07 PM
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What are the basic things that I need to know?
One of the subs you should contact should be an electrician.

Sorry to be a killjoy but these questions you have are basically everything you need to do the job. If you do not have the basic electrical knowledge to start off you should seriously consider subbing this out.

For one thing, NO, you cannot use the "heavy wires" coming into your main panel to feed a sub.
Old 08-29-04, 06:12 PM
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First of all, you need to make a good estimate of the amount of power you will need. This will depend on what is out there and how much of it might be used simulataneously. If this is just a one-person shop, then perhaps only one tool plus a vacuum system will be in use at a time. Then think about how and if you will heat and/or air condition the space, and how much power that will take. Then consider whether you will have a refrigerator and/or freezer, a television, a water heater, or other stuff. If welding is in the picture, then that will play a very large role in your power needs. Small needs such as lighting and a radio, etc., will contribute very little to the total load.

A 100-amp feeder using #2 copper wires (three plus ground) from a 100-amp breaker in the main panel, buried at least 18" deep in conduit, is probably what you will come up with. This will provide 24KW of power, which should be enough.

The 100-foot distance is not so far as to require a lot of special consideration.

A careful assessment of your needs is the first step.

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