Looking for a little electrical advice from the pro's on CP. Planning to finally run power out to a small shed ~110' total from my main house breaker. Just looking to run two 20A 110 circuits and switched lighting (since 220 and 110 would require much more).
Two options are currently tempting me: running a 12-3 multi-wire circuit or a 10-2 (or 10-3) to a sub-panel and distributing from there.
Any thoughts/considerations are welcome!
-Dirty
To properly understand what you are trying to accomplish you would need to set down and on paper get a good understand what you need and want to do with the shop. What are your needs in the future. Today is easy... tomorrow ??? But then I read and you are also referring to it as a shed.... This tells me a couple circuits as you describe with a light. Not a 220 volt table saw, nor a double phase planer and a 220 air compressor all running at the same time.
If it were the latter the shed I would run a small sub-panel with a disconnect and a direct burial line in a 10 - 2. If you are looking at the former and not the latter I would look at of course a separate service and lots of $$$.
Where is the power for the shop/shed originating from? If the shed/shop panel is a sub panel you'll need to run 3 wires for 110 or 4 wires for 220 as well as grounding the panel to a couple grounding rods. And like Rick said, I'd tend to go heavier rather than lighter on the cable to cover future uses. I'd seriously consider running 220 out there, it's only one more cable.
Alan
QuoteJust looking to run two 20A 110 circuits and switched lighting
Does that mean you want to be able to run two things at one time, things that might use up to 20 amps each? Lights can be LED so they don't use much power at all. Does the 110 feet include the vertical distances up and down the walls? BTW, line voltage is 120 VAC in most places today, not 110 VAC.
12 gauge wire over a 110 foot length for 120 VAC, 20 amps will have a voltage drop of 7.33%. 10 gauge would = a drop of 4.4% or 5.28 volts. Usually system designers try to limit the drop to 5%. Of course when less than 20 amps is being drawn the % drop will be less; 10 amps = 2.20% voltage drop (2.64 volts) over 10 gauge wire.
Will there need to be an inspection? There may local rules on wire sizes for outbuildings at certain distances.
Will you want a sub panel w/breaker(s). Long walk back to the main panel. ;D
You are sort of 'ifffy' on your voltage drop at 110 feet assuming it is 110 ft total. If it is surface distance and you start adding in the rises to the runs you will be maxing out MD's 5% I have gotten away with it around here some how ??? It should not work as well as it has. I do not attempt to over tax the system other than an irrigation pump on my longest run. :o
If you are running the wire, and digging the trench, my thought is you might as well go 220 to a sub panel. You can get really nice square d homeline box that comes with breakers for under 50 bucks. You can feed how ever many amps you want into the sub panel as long as you match up wire size with the breaker. I ran 40 amps to my shed.
With that much distance 10 gauge would be the minimum. I got into the voltage drop thing when running a line to my cabin. It had to go over 300 ft so they had to bring the high voltage lines into a box which then dropped down to the "normal" stuff. I think the maximum for the normal stuff was 150-200 ft. I can't really remember now. Point is you don't want too much voltage drop.
This is a linedrop calc I wrote awhile ago;
http://www.timbertoolbox.com/Calcs/linedropcalc.htm
A 220 line can carry double the amperage, or at the same amperage the % voltage drop is halved. For the money the extra wire is worth it.