Forum Discussion

kohldad's avatar
kohldad
Explorer III
Nov 05, 2014

30A/20A pedestal

For some reason I'm drawing a blank though I could wire a complete house and have done so in the past.

Installing a 30A/20A pedestal with breakers at my daughter's house. I want to have full use of both outlets at the same time so when we have two campers they each have a plug. Purchased a pre-wired 30A/20A box which will only be about 15 feet from the meter combination box. I have room for two breakers in the box.

Thinking I should just install a double 30A breaker in the combination box, run 10-3 in buried conduit to he pedestal.

Problem I'm having is since I will be using each outlet separate, will the 10 ga neutral be sufficient or should the feed actually be #6 to have the neutral large enough to handle the return for 30a and 20a outlet combined?

16 Replies

  • #10 neutral is fine for 15' split phase service up to 30 amps.
    Split phase neutral only carries the differential in current so 30a max.
    Similar to the laundry connection using split phase on a duplex outlet.
  • DrewE wrote:
    For conduit, you need four separate wires rather than 10/3 + G cable. The wires need to be rated for wet locations (which commonly available separate wires generally are). So you'll either need to run the conduit all the way to the main breaker box, or have a box midway at some convenient place to transition from the cable to the wires in conduit.

    (I think the code doesn't technically forbid using cables in conduit, but it does impose some additional size and derating requirements. Regardless, underground wiring in conduit needs to be water rated, so ordinary romex is out of the question. Pulling individual stranded wires is also a lot easier than pulling multiconductor cable, especially as the cable usually has solid conductors.)

    If your pedestal allows for it, and I suspect it probably would, I might consider installing a 50A dual breaker for the main in the house panel and, of course, running the appropriately sized wires for 50A. That way, should there be a desire at some point in the future to upgrade to a 50A pedestal, only the pedestal needs to be changed.
    This works as long as the pedestal has its own breakers for the 30amp and the 20amp.
  • For conduit, you need four separate wires rather than 10/3 + G cable. The wires need to be rated for wet locations (which commonly available separate wires generally are). So you'll either need to run the conduit all the way to the main breaker box, or have a box midway at some convenient place to transition from the cable to the wires in conduit.

    (I think the code doesn't technically forbid using cables in conduit, but it does impose some additional size and derating requirements. Regardless, underground wiring in conduit needs to be water rated, so ordinary romex is out of the question. Pulling individual stranded wires is also a lot easier than pulling multiconductor cable, especially as the cable usually has solid conductors.)

    If your pedestal allows for it, and I suspect it probably would, I might consider installing a 50A dual breaker for the main in the house panel and, of course, running the appropriately sized wires for 50A. That way, should there be a desire at some point in the future to upgrade to a 50A pedestal, only the pedestal needs to be changed.
  • when running opposite phases, the neutral would only take the difference

    so with a 30 amp one side and 20 amp on the other side the neutral would only be pulling 10 amps


    That is where my thinking was flawed.

    I can get by with a double 30A in the combo box because the breaker only protects the run. The pedestal has a 30A and 20A breaker protecting the outlets.

    Reason for a 20A plug is it is GFI and will be used for other things. Only a small truck camper will be using it, not a large RV with high loads so the 20A will be enough.

    Thanks for the quick response.
  • kohldad wrote:
    For some reason I'm drawing a blank though I could wire a complete house and have done so in the past.

    Installing a 30A/20A pedestal with breakers at my daughter's house. I want to have full use of both outlets at the same time so when we have two campers they each have a plug. Purchased a pre-wired 30A/20A box which will only be about 15 feet from the meter combination box. I have room for two breakers in the box.

    Thinking I should just install a double 30A breaker in the combination box, run 10-3 in buried conduit to he pedestal.

    Problem I'm having is since I will be using each outlet separate, will the 10 ga neutral be sufficient or should the feed actually be #6 to have the neutral large enough to handle the return for 30a and 20a outlet combined?


    you would actually need a 30/20amp breaker, since the outlet rating would be over

    i would install dual 30's and use 10-3 with ground.

    when running opposite phases, the neutral would only take the difference

    so with a 30 amp one side and 20 amp on the other side the neutral would only be pulling 10 amps

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,283 PostsLatest Activity: Jul 17, 2025