I've just added a new garage and bedroom and am about to wire them. I've done a lot of wiring in my house, know all the basic requirements for how wiring is run, etc, never had a problem with inspection. But I've never done a garage or bedroom. I also haven't carefully explored which circuit I can easily splice into yet. I want to check the following assumptions.

Garage: going to splice into a circuit that has some outlets elsewhere. I will wire for 20A but use 15A outlets.

  1. One circuit in garage for outlets, wired for 20A, GFCI'ed, shared with other power in some other rooms at my discretion. I will make sure I'm not worried about so much shared that I will blow the circuit using power tools in the garage.
  2. Garage lighting to be run at 15A, most likely shared with some other lighting circuits in the house.
  3. Bedroom: Is it the case that I need an AFCI circuit breaker for any circuit (including lights and outlets) in the bedroom?
  4. Is is allowed to shared the circuits in the bedroom with the garage? Is it a bad idea to have the garage AFCI'ed and GFCI'ed?
  • 2
    Why are you looking to splice into an existing circuit? Does the service panel have room for more breakers?
    – wallyk
    Dec 6, 2013 at 19:14
  • 3
    In general, it is better to put everything on a separate circuit if possible. If you don't have room in the main panel, maybe it is time to upgrade. Also, is the garage attached? If not, just make sure to use a proper cable since you are not allowed to bury regular romex
    – Yuriy
    Dec 6, 2013 at 19:40
  • This question may be too broad to answer properly, in this short answer format.
    – Tester101
    Dec 6, 2013 at 21:38

1 Answer 1


As recommended by wallyk and yurly, add another circuit or two. There is usually no way to tell exactly how may outlet and switches etc., are on the same circuit. If there is no spare breakers in the breaker panel, use tandem breakers. This will allow two circuits to reside in the same space as one.enter image description here

There are tandem breakers available by all manufacturers, I believe.

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