metagami
Sep 26, 2006, 02:39 PM
My winter project is to build a 12x20 shed in the far corner of the back yard. I'd like to run electric service for lights and power tools. On the outside of the house about 30' from the main panel I have a 240V pullout switch that at one time supplied an AC compressor (since relocated to the other side of the house). It's connected to two 30A breakers in the main panel. The electrician who did the AC work said the switch would be a fine starting point to run service to the shed, which will be 65' from the pullout switch. So here are my questions:
1. Given the total distance, what's the correct wire size? I'm guessing 8-3, but would 6-3 be better?
2. The wire will run underground across the back yard. Is there a special rating or designation for wire that will be buried about a foot deep?
3. Do I need to run conduit from the switch down the wall and into the ground? I would probably want to do that even if it isn't actually required.
4. The shed will sit on a slab. I'll install conduit when the slab is poured so the wire can enter below ground then come up inside the wall. Can the conduit be cut off flush with the slab, or does it need to run all the way up to the subpanel?
5. Should I connect the subpanel ground bar to the ground wire coming from the main panel, or should I install a ground rod outside the shed and connect to that instead? I think the ground rod may be required. In that case, do I connect the ground wire coming from the main panel to anything at all? I understand the neutral bar must not be bonded to the subpanel ground.
6. Should the subpanel have its own main breakers, or should the incoming supply simply connect directly to the buss bars?
7. The receptacles will all be 20A using 12-2. Should (or must) they have GFCI? If so, is it better to use a GFCI breaker, or just use a GFCI receptacle as the first one in the circuit, with the other receptacles connected to the first? Is there a limit to the number of receptacles that can be connected "downstream" from a GFCI receptacle?
8. Is there a maximum number of receptacles allowed on a single 20A circuit?
9. I'm not planning on finishing the inside walls, so the studs and all the wiring will be exposed. Can I still use Romex, or is armored cable required? If the walls were going to finished, I'd just drill holes through the center of each stud and run Romex straight from box to box. In this case, though, that seems like it would create a hazard. Perhaps the wire should drop straight down along each stud from the ceiling?
10. Since I know I'm not going to be finishing the walls, should I still mount the boxes so they stick out 1/2" from the studs, or just mount them flush with the studs?
11. My plans call for ten 120V/20A receptacles, two 240V/30A receptacles, two interior fluorescent lights, and two exterior incandescent lights. In practice, at most the lights and a single power tool would ever be in use simultaneously. Are the two 30A breakers enough, or should I figure out some way to upgrade to 50A from the main panel?
Thanks for any advice you can offer!
Tim
1. Given the total distance, what's the correct wire size? I'm guessing 8-3, but would 6-3 be better?
2. The wire will run underground across the back yard. Is there a special rating or designation for wire that will be buried about a foot deep?
3. Do I need to run conduit from the switch down the wall and into the ground? I would probably want to do that even if it isn't actually required.
4. The shed will sit on a slab. I'll install conduit when the slab is poured so the wire can enter below ground then come up inside the wall. Can the conduit be cut off flush with the slab, or does it need to run all the way up to the subpanel?
5. Should I connect the subpanel ground bar to the ground wire coming from the main panel, or should I install a ground rod outside the shed and connect to that instead? I think the ground rod may be required. In that case, do I connect the ground wire coming from the main panel to anything at all? I understand the neutral bar must not be bonded to the subpanel ground.
6. Should the subpanel have its own main breakers, or should the incoming supply simply connect directly to the buss bars?
7. The receptacles will all be 20A using 12-2. Should (or must) they have GFCI? If so, is it better to use a GFCI breaker, or just use a GFCI receptacle as the first one in the circuit, with the other receptacles connected to the first? Is there a limit to the number of receptacles that can be connected "downstream" from a GFCI receptacle?
8. Is there a maximum number of receptacles allowed on a single 20A circuit?
9. I'm not planning on finishing the inside walls, so the studs and all the wiring will be exposed. Can I still use Romex, or is armored cable required? If the walls were going to finished, I'd just drill holes through the center of each stud and run Romex straight from box to box. In this case, though, that seems like it would create a hazard. Perhaps the wire should drop straight down along each stud from the ceiling?
10. Since I know I'm not going to be finishing the walls, should I still mount the boxes so they stick out 1/2" from the studs, or just mount them flush with the studs?
11. My plans call for ten 120V/20A receptacles, two 240V/30A receptacles, two interior fluorescent lights, and two exterior incandescent lights. In practice, at most the lights and a single power tool would ever be in use simultaneously. Are the two 30A breakers enough, or should I figure out some way to upgrade to 50A from the main panel?
Thanks for any advice you can offer!
Tim