100 Foot Run for 20A Breaker

Old 09-25-20, 09:06 AM
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100 Foot Run for 20A Breaker

Hello all,

I am soon to be in the process of finishing the rest of my basement and have a quick question on running the wire. My planned shop is at opposite ends of Breaker box in the garage top level and planned shop in the basement. I like being able to use my table saw and or a 120V compressor in that location. Currently it pops the breaker every now and then when I turn on the saw and the vacuum at the same time... When the saw is under load. Right now I use an extension cord to reach a 20A outlet in another room. This was wired with the house.

My thought was to run another line of 10/2 to a 20A outlet so that the thicker line will more easily be able to handle the run of 100 feet or so. Is my thinking correct? If so, that 20A circuit would run all my outlets down there. Rarely would I have two machines on at the same time, other than the saw and the vacuum.. To keep dust down. I'd run another lighting circuit on 14/2 for the recessed lighting using LED lights.

Old 09-25-20, 09:11 AM
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Yes, your thinking is correct. A larger gauge wire can handle current with less of a voltage drop. You can search online for "wire length voltage drop" and charts and calculators will appear to allow you to calculate the voltage drop over your run for different wire sizes. But, bigger wire is better. The only downside to heavier gauge wire is the cost and difficulty of working with the wire.
Old 09-25-20, 09:26 AM
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Any room left in your panel?
If so and it was mine I'd be adding a double 60 amp. breaker and adding a 6 breaker subpanel in the shop.
That way you would have more then enough power, not have to run all the way back to the panel if one did trip, if you needed 220 volt it would be avalible.
The outlets in the shop also should be GFI's
Old 09-25-20, 10:37 AM
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I like Joe's suggestion. But if you wanted to go a middle-ground, another option is to run a 20A MWBC (multi-wire branch circuit).
I would use 12/3 (plus ground) cable and connect to a double-pole 20A breaker. In your garage, you can then connect to two separate GFI receptacles, using the red-hot and black-hot and sharing the neutral. For a little extra cost of the 12/3 over 12/2, now you have two 20A circuits for your use.

In my opinion, I would rather do this than bother with 10/2 cable for a 100' run. (If you had 150' or 200' run, I'd feel differently).

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