I am running power through a conduit to a detached shop, 80 feet of wire, a 60 amp panel. What size and type of wire do I need?

  • Do we have a good canonical Q and A for these sub-panel questions? This is a good one as well as this one. We get the question a lot.
    – JPhi1618
    Mar 18, 2019 at 20:04
  • @JPhi1618 unfortunately not, as there are twists much of the time.... Mar 18, 2019 at 23:16
  • Do you have the panel installed already, or would you be open to a larger panel? Also, what size and type of conduit do you have in, how many square feet is the shop space, do you have HVAC there, and what sorts of tools are you going to be using there? Mar 18, 2019 at 23:17
  • 16mm^2 is adequate
    – DDS
    Mar 19, 2019 at 10:08

1 Answer 1


If the entire run is in conduit, you need individual wires rated THWN, THWN-2, or XHHW-2.

The size of wire is 6 AWG in copper or 4 AWG in aluminum. Either one is rated 55A but you are allowed to round up. Also you are allowed to use bigger wire than strictly needed; if you use #3 copper or #1 aluminum you could increase amperage later to 100A.

The panel is required to have a shutoff switch because it is in an outbuilding. The cheapest way to get a shutoff switch is use a panel with a main breaker. The main breaker can be any size, since it's only serving as a shutoff switch.

When your subpanel has a main breaker, that means the subpanel can be any size. We strongly recommend a significant number of spaces, many more than you immediately expect to use. Spaces are dirt cheap when you are initially installing the panel, but it is rather pricey to replace a too-small panel. Panels with more spaces tend to be larger than 60A, but it is fine to have a 60A breaker feed a 125A subpanel. It can't do any harm.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.