I have a 20 amp breaker and 12 gauge wire running out to a shed that is wired with 14 gauge wire. The shed has 3 receptacle, 1 light switch and 1 light receptacle. Is this safe?

  • How. Far from panel to shed? What will you be plugging into shed receptacles? – Kris Sep 27 at 13:39
  • What are you using as a disconnecting means at the shed? – ThreePhaseEel Sep 27 at 16:46

No. You must not have any 14 Ga wire on a 20A breaker. Change the wire to 12 Ga or the breaker to a 15A.

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  • 6
    To expand on this. There will be no warning, no sirens, and it will seem things are ok. When you exceed 15A on that circuit, the wire will burn down whatever it is run through, and the fire department will find out the wrong wire is used and you will not have insurance coverage, if you lived to worry about insurance. – Nelson Sep 28 at 16:33
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    I would think it might be advantageous to the 12ga wire feed a subpanel within the shed that contains one or two 15A breakers. If one can split the shed wiring into two 15A circuits, this would allow the shed to safely use more than 15A provided that no more than 15A was on either circuit. Even if one only uses a single 15A circuit, I would think having a 20A breaker in the main panel and 15A in the shed could be advantageous both because moderate overload conditions would be likely to trip the shed breaker while leaving the main breaker untripped (note that short circuits... – supercat Sep 28 at 16:39
  • ...would likely trip both). If one would be using tools that might sometimes cause an overload (e.g. if a saw or drill gets bogged down in material) being able to reset a breaker in the shed may be more convenient than having to visit the main panel. – supercat Sep 28 at 16:50

You could install a pony panel in the garage. Where I live, the panel needs to be more than 3 feet above the ground, but within 6 feet of where the power enters the structure. Please check you local electrical code. You would install a small breaker panel with a 20A disconnect and then 15A breakers for your circuits on 14 Ga wire. This would allow you to have your light on one local circuit and the outlets on other circuits, so, if you trip one of the outlet circuits, the light will stay on.

You can use a single phase, 120V panel with 4 or 6 slots. One of the slots would be your 20A disconnect; a regular breaker with the "load" connected to the supply. It looks a little funny, but it will work and it should meet code.

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