I want to provide electrical service to a home office located in an out-building about 75' away from the house. Because electrical service enters the house at the far end, the total one-way run length is about 150'. The calculators online say I need to use #8 wire for a 15a/110v circuit and #6 wire for a 20a/110v circuit. The first 75' will be in a crawlspace under the house. The last 75' will be in PVC conduit underground. Intention is to bring up the power adjacent to the home office on a pole with a waterproof in use cover, then take the circuit into the building via an extension cord.
I'd like you folks to validate what's above and these plans:
- do not run a ground wire. Use a ground rod at the destination.
- either run THHN wire in conduit under the house, or run shielded cable to a J-Box, then go from there with THNN wire in conduit underground.
- looks like 2 #8 or #6 wires will require 3/4' PVC conduit, but if I upgraded to 1" conduit, there would be room for another pair of either size.
- since the end of this is simply a jbox containing two 110v outlets, how do I connect #6 wires? Just use #12 wire from the outlet to the #6 wire and a wire nut?
- the equipment intended for the room is a space heater (1500w), a computer with monitor (not much) and a light (150w). That seems to me to be pushing a 15A circuit so a 20 would be better (actually 2 15's would be better but require bigger cables)