Using Half Of A Double-pole Breaker. - Electrical - DIY Chatroom Home Improvement Forum

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Old 04-04-2011, 04:11 PM   #1
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Using half of a double-pole breaker.

I have a 50amp/240V Spa GFCI disconnect panel on the back of my house. I no longer have a spa, and the panel is not being used for anything. I want to add a 20amp 110v outlet next to the panel.

Is there any issue with borrowing 1 of the hot wires from the panel, along with the neutral and ground? I would just put a cap on the other hot wire. I know the voltage would be right, but my concern is that the breaker back in the Main panel is 50amps, so it would take a lot to trip it.

Thanks in advance.


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Old 04-04-2011, 04:25 PM   #2
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I'd replace the disconnect with an outdoor subpanel with a couple circuits in it. You can pick up a 2/4 70 amp outdoor subpanel new at Lowe's for $20. That way you can size your breaker as you want. Either that or replace the breaker in the main panel with a single pole breaker of the correct size.


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Old 04-04-2011, 04:31 PM   #3
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You are right in that the breaker is too big to trip a 20 amp circuit. The 50 amp breaker is protecting the wire that is there now. The easiest thing to do would be to replace the breaker with a 20 amp breaker but the wire is likely a #6 and I am not sure that it would fit a 20 amp breaker. You could replace the spa disconnect with a small sub panel and install a 20 amp breaker in it and run your new circuit from there.
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Old 04-04-2011, 05:05 PM   #4
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Thanks for the replies, gentlemen. I like the idea of the outdoor subpanel, and will pursue that. Just for the sake of curiosity, would it have caused a problem to use just one half of that double-pole breaker? I know the amperage of the breaker was too high, but beyond that using 1 hot wire would just be a normal 110v right?
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Old 04-04-2011, 05:37 PM   #5
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Simply using one half of a double breaker is not a problem.
You will get the 120 volts.

But ordinary lights and receptacles must be protected by breakers not greater than 20 amps, hence the idea of a subpanel.
The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.
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Old 04-04-2011, 06:44 PM   #6
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If you're going to do that, may as well use the whole breaker and make it a MWBC. But since the breaker is over 20 amps I'd just go with the mini sub panel idea mentioned.


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