Upgrading a 15 amp circuit to a 20 amp circuit

Old 10-25-05, 02:51 PM
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Upgrading a 15 amp circuit to a 20 amp circuit

I have a fairly new house (10 years old) which has a garage outlet that has a 15 amp GFI circuit breaker. I just bought a new Craftsman air compressor which is rated at 120v/15amps. However, I suspect that the load is a little higher at startup and that it really needs a 20 amp breaker.

Can anyone offer some advice here? Is it possible to upgrade the breaker to a 20 amp breaker? This circuit is a short run (2 feet) just below the panel box.

Thanks in advance for any advice.
Old 10-25-05, 02:58 PM
Join Date: Sep 2000
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First, try your compressor on your existing circuit. It's possible that you need do nothing. A 15-amp breaker will allow an overcurrent long enough to start most motors. It might work for you too.

If you do need a 20-amp circuit, and unless your panel is full, I suggest you leave the 15-amp circuit alone and add a new 20-amp circuit. You can't use the existing wiring anyway because the gauge is wrong. For a short run, it's pretty easy, although working inside the panel has more hazards and requires more craftmanship than your standard receptacle wiring.

Read a few books on home wiring. These kinds of projects are typically well-covered.
Old 10-25-05, 02:58 PM
Join Date: Sep 2003
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You will need to replace the breaker and the wires to the receptacle. You need 12 gage wire and a 20 amp breaker. If you are in Canada you also need a 20 amp receptacle, whereas in the US you can use a 15 amp receptacle, as long as it is a duplex receptacle, or you can install a 20 amp receptacle.

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