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From a 240volt 50amp breaker in my main panel I've run 2 hots, a neutral, and ground to a sub-panel in my outdoor shed. Do I have to install 2 120volt breakers, is there a way to just use one?

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Main (240 volt) 50 amp -> 8 gauge stranded (2 hots, white, green) -> 16-50 outlet -> 8 gauge -> outside disconnect panel (30amp 120) -> 8 gauge -> shed panel 20 amp.

I ran the extra hot to the shed in case I ever needed 240 in future. But the 50amp is tripping when I try to turn on the 20 amp. Since it sounds like it's not unbalanced load, my outlets are maybe wired wrong?

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  • You have two hots in the shed. If you instal only one breaker on one hot, what is the other hot doing ?
    – Traveler
    Oct 15, 2022 at 19:00
  • Are you talking about the main breaker that the two hots connect to, or just placing a single breaker for a circuit in the building? Can have just a single breaker for a branch(room) circuit.
    – crip659
    Oct 15, 2022 at 19:31
  • I ran two hots because the breaker in main I am running the cable from was 240. Also in case I ever need 240 I don't need to run cable again Oct 15, 2022 at 20:28
  • Your description is unclear.
    – Hot Licks
    Oct 15, 2022 at 22:02

2 Answers 2

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What size cable did you run to the 50 amp breaker? If you only need 120 volts and it's for light load then you only need to install one single breaker. If you've got a lot of 120 volt load, two breakers on the two legs would be good for balancing the load. You'd also need the two breakers for any 240 volt load.

Since you have a GFCI for the 50 amp breaker, make sure your sub panel neutral goes to the load neutral on that breaker. If that neural goes to the neutral bus in the main breaker panel, the 50 amp breaker will trip on any load. There should be a white wire, sometimes coiled, coming out of the bottom of the GFCI breaker. That wire goes to the neutral bus. Then there should be another terminal, load terminal for the neutral to your sub panel.

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  • I am running 8 gauge stranded from main, to the shed Oct 15, 2022 at 20:29
  • The 50 amp is in main panel, then the sub panel is 20amp, but the 240 volt breaker is flipping when I turn on the 20amp. So was wondering if it was because the load is unbalanced Oct 15, 2022 at 20:31
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    If an upstream breaker is instant-tripping when you turn on a downstream breaker, then you probably have a dead short in the circuit you're trying to turn on. Unbalanced loads wouldn't trip a breaker
    – maples
    Oct 15, 2022 at 20:34
  • @SeanMcCully So switching on a 20 amp breaker trips a 50 amp breaker? Something's wrong with your circuit or the 50 amp breaker. Is the 50 am breaker a GFCI breaker?
    – JACK
    Oct 15, 2022 at 20:41
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    @SeanMcCully Move it to neutral load terminal on 50 amp breaker.
    – JACK
    Oct 15, 2022 at 23:09
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Yes, no problem. You can install just a single breaker on one of the legs, no need to balance unless you are running heavy loads. Imagine two breakers in the panel, one is running nothing at a particular time the other is running everything in use (probably not much), that would be same as having the first breaker not be there at all.

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