Electric Service to the Shop Building
I will be building a shop building later this year.
I have a buried 200A service to the house with a 200A breaker at the meter and space in the panel for additional breakers. There is also a 200A Panel in the basement with a main 200A breaker.
Other than saving two slots in the panel in the basement, is there any reason to run the service to the shop building directly from the meter vs. from the panel in the basement? The panel in the basement will be about 75′ closer to the shop building. I am planning to run at least 100A and possibly 150A service to the shop building (I’m still sizing the welder and phase converter in the shop and want to make sure I have sufficient juice for the minisplit and compressor while welding).
It seems like using the basement panel would make the most sense, especially if I install Solar in the future.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
You won't have any problems running the circuit from the panel in your house. You'll need to run a four wire cable though, since you'll have to keep ground and neutral seperate in the new subpanel in your shop. I would recommend running individual conductors in PVC conduit for this purpose, and I'd make sure to install at least one additional 1" PVC conduit in that trench to allow for future communication wires. Two 1" conduits gives other options, such as multiple switches allowing outdoor lights to be turned on from any building (something I did at my family's cabin, for example). This is all easy to do if you have spare conduit runs, but not so easy if you have to do more trenching in the future.
Note that you're usually limited to 100A breakers in typical residential panels, and when installing 100A breakers, you'll find the spaces opposite them in the panel (that share the same stabs on the bustbar in the panel) will be limited. This is because there is a maximum current rating to each breaker location on the panel busbars. If you want to run 150A service to your shop, you'll probably need a commerical-type panel that allows for larger breakers, you would then feed this panel from your meter (using the existing wiring), and that panel would then serve your house panel and your shop panel.
BTW, you can save some money using aluminum wire between your home and shop. This is fine, but I'd recommend using compression connectors (big crimp lugs), and not the mechancial screw lugs if you do this. If you do end up using aluminum wire and mechanical lugs, be sure to use the no-ox paste for aluminum wire and APPLY IT CORRECTLY (work it between the strands). This is important on any circuit that might seed occassional heavy loading. Compression lugs are much, much better if you have the tooling to install them.
Bill