||07-07-2008 11:38 PM
Outbuilding wiring and underground wiring questions
First off, I am not an electrician, so my apologies in advance for any REALLY stupid statements/question. ;-) I plan on doing research for my project, doing the grunt work, like pulling wires/cables and such, and then letting a licensed electrician review it all, make connections, and power it all up! That said, here's my situation:
I have a 200A main service in the house I bought last year. I also have a 600 SF outbuilding I plan to convert to a small shop/studio. It is about 175 feet from the main panel in the house (in the attic level, actually) The previous owner had the same idea, and already ran a couple PVC conduits from the house to the outbuilding, underground, though I don't know the depth yet. Going by memory here, one conduit is 2" diameter and one is about 3/4" diameter.
My little shop will probably have a table saw, a drill press, a disc sander, scroll saw, and radial arm saw as its main "equipment", along with some shop lighting, maybe a window mounted air conditioner, stereo system/radio, and hopefully, computer capabilities. It will be only me in this shop, so only one "tool" would be running at any one time.
My questions are: How would I determine the wire size for this load and this length of run? Would a 60A sub-panel be adequate? Is PVC conduit OK for this kind of thing, and what depth is required by code?
From my reading, I believe that the panel size is OK, and will require a separate grounding rod bonded to the ground terminal in the sub-panel, and the ground and neutral will need to be separate in the sub-panel as well. Right? Additionally, my GUESS is that romex is the wrong way to go, and that maybe 10/2 wire is OK to pull for this application, on a GFCI from the main panel?? Another post I read said something like "Pull 3, #8 THWN (2 blacks and one white) and a #10 green" for a similar situation?? Was planning on a 12 space/24 circuit panel.
So what have I got right, and what have I got wrong? Any other suggestions/comments are most appreciated.