I'm building a shed that will be housing a washer, dryer, hot water heater, and a freezer. The dryer and water heater both require 220V 30A and will be used concurrently.
The washer and freezer use 120V 15A connections (not sure how much they actually draw), the freezer will run continuously. I'd also like a light fixture and a 3rd 120V outlet.
The main is 200A service. I have an existing subpanel (100A) that supplies my camper.
For the shed, I'm considering another 100A subpanel. The shed is 30 feet away from the main, and I'm going to bury the cable underground (with or without pvc conduit depending on recommendations here.)
Is 100A sufficient? Or overkill?
What wire size would I need from the main panel to the subpanel?
I think I need to run 4 wires (two hot, a neutral, and an equipment ground).
Is this correct?
Best Answer
For the sub panel sometimes you can get a better deal on a 150 amp panel your panel really cannot be two large. Yes you will need a 4 wire feed but your main panel will dictate the size feeder wires , if I was doing this and could get a 125a breaker to feed my shop I would do it, however many panels will max out at 100 amp so size your feeder wiring on the size of your breaker. The size of the sub panel is not the controlling factor it’s the breaker in the main that feeds the sub your sub has to be at least that big but going bigger is usually considered better. Large feeders , most pros will pull aluminum no worry about voltage drop here and with large conductors conduit and individual conductors are the way to go the ground wire will be much smaller based on the size, yes the other conductors are based on size but grounds are a different table. You also need a local grounding rod for the sub.
So go big on the sub panel even If you only want 80 amps, use conduit PVC is easy to cut and glue schedule 80 above ground 40 below ground, IF you use a smaller wire size do your self a favor and over size your conduit 1-1/4” or 1-1/2” will make an easier pull with large aluminum and if you decide to go max size later it make using the existing conduit possible and a later upgrade simple. Newer code mandates all receptacles to be GFCI protected.