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  1. #1
    Join Date
    May 2010
    Posts
    65

    Default Switches on 20A/12ga circuit

    Please confirm/deny my understanding of code -

    On a 20A/12ga circuit, one does not necessarily need to use 20A switches. Instead the switch rating is determined by the actual load being switched. Simple example being a 20A splitting off into two branches, each of which has an 8A load. Each branch would be fine with a 15A switch, correct? If the circuit comprised a single switched 16A load, then a 20A switch is required.

    I know that the physics hear is right, but physics and code don't always agree...

  2. #2
    Join Date
    May 2010
    Location
    New Mexico
    Posts
    35

    Default Re: Switches on 20A/12ga circuit

    That is my understanding. (I'm NOT an electrician) Switch sizing is based on the load being controlled by the switch, usually measured in watts. Most common, big-box store switches will be 600W. So, 8 - 60W light bulbs (80% of max rating).

    Also, I'd size for the maximum possible forseeable load. e.g. you can safely put 20 CFLs on the circuit, but the next homeowner my change them out for incandecents. Or you may decide you do more reading in one area and change out some bulbs to 100W instead of 60W. yadda yadda.

    High wattage switches are available from electrical suppliers, but they start getting expensive.

    John

  3. #3
    Join Date
    May 2010
    Location
    New Mexico
    Posts
    35

    Default Re: Switches on 20A/12ga circuit

    DS - been doing a lot of work with dimmers lately, so that was in the front of my head. Thanks for the clarification.

    BTW, did you know that a $150 Lutron 1500W dimmer will happily act as a circuit fuse, keeping you from having to reset your circuit breaker? Found this out after installing some new lighting and had a wire come loose. Expensive lesson.

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