I'll try to keep this short but there is a bit of background info that may be needed. Couple of days I rented a floor grinder to eliminate uneven concrete floor in the basement. The grinder kept tripping the breaker every 10 or so minutes. All the circuit breakers in the main panel are 10 amp. Needles to say I took the equipment back and was told that this kind of equipment requires a minimum of 15 or 20 amp circuits.

Quite disappointed not being able to finish the project I started thinking and I realized that recently I added a new sets of duplex GFI outlets (one GFI and 3 regular) in the garage using a #12 wire but only a 10 amp breaker to match the rest. Can I replace the 10 amp breaker for a 20 amp? I mean the 12 gauge wire should be OK, I just wondered why the builder chose 10 amp breakers in this house.

  • Also, 10A breakers? That's mighty strange for the USA... Jan 7 '17 at 23:17

The short answer is that the breaker protects the wire (otherwise, heat and fire can result). You can put a 20A breaker on a circuit if all the wire on the circuit is #12. If any of the wire is #14 you can put a 15A breaker on it. If any of the wire in the circuit is smaller than #14, then you cannot put a 15A breaker on it.

  • Thanks, I thought that was the case. All the wire is #12.
    – Risho
    May 26 '15 at 2:20
  • 5
    +1 But that means ALL the wire, including the wires to any light fixture, not just the wire to the outlet you are using for the grinder.
    – bib
    May 26 '15 at 2:48
  • Yep, all the way to the fixture itself (smaller wires inside of fixtures and devices don't count). May 26 '15 at 5:01
  • Also make sure the outlets are rated for that amperage. May 26 '15 at 12:50

99.999999% you do not have 10 amp breakers!

Recent Household breakers are clearly labeled 10kA interrupting, this rating can often be much easier to read than the Amp rating of the circuit breaker

The interrupting rating is the current (10,000 amps) that they can withstand and still manage to shut off. If such a catastrophic event did occur there is a pretty good chance they would not survive but they would have given their life to save the house.

The amp rating is often embossed or printed on the handle. 15, 20, 30, 40, 50 amp are commonly used for circuits in homes.

Most manufactures do make a 10 amp model but it is very rare, you will not find them at Home Depot, Lowes, or Menards and even an Electrical supply house usually would have to special order one.

I do realize this is an old thread, I hope this information will help someone who gets here from a search

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