I need to install a 30 amp 120v RV outlet 140 feet from main box. I thought I would use a sub panel to allow for a few lights and two 110 outlets. Can I use a double pole 30 amp breaker with number 4 wire? My thoughts were since I was useing a double pole breaker I could use one hot to feed the rv plug and the other the rest. Thanks DC

  • Are you thinking of copper or aluminum for the 4AWG wire, and can you post photos of said main box? Dec 9, 2018 at 22:35
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    I would consider getting an RV power pedestal. You normally feed these with 50 amp 240v feeder. The pedestal has the breakers in it for the standard RV 120v 30 amp outlet, also a 50a 240v outlet and a 120v outlet this would provide the safety and multiple circuits you want with a future 50 amp outlet that many RV's are going to today in fact the 2017 code increased the requirement for 50amp % from 20% to 40% so this may be worth a little extra today to future proof the setup. They do make 30amp / 20 amp pedestals with the outlets and breakers.
    – Ed Beal
    Dec 10, 2018 at 16:44

1 Answer 1


To answer your question, the smallest sub panel you can find. You would need to use conduit and correct fittings for running wire. However, I wouldn't buy a sub panel for just one double poll breaker. Instead, since this is a sub panel we're talking about here, I would set up a two or three breaker sub panel. 1 or 2 for the lights and other outlets, and 1 for the RV outlet. For the RV outlet, if it is a 120V outlet, which I think it is, they make up to 50 amp single poll Square-D breakers. Although, you would need a 40 or 30 amp single poll. For the other breaker(s), I would use a 20 amp. Just a suggestion...

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    GAH! That's exactly backwards -- you want the biggest subpanel you can find, spaces-wise, so you don't have to go back and replace the thing when you run out of spaces down the road! Dec 10, 2018 at 12:46
  • Also the lights could not be on a 30 amp half of the single double pole breaker.
    – Ed Beal
    Dec 10, 2018 at 16:34

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