need some advise

Hoonin · 01-25-2004, 05:10 AM

I wired a storage building I just bought. For now I have all four 120v/15amp outlets and two lights wired with a pig tail that I plug a cord into to put power to the building. What I would like to do is straight wire it. I plan on putting a 120v/20 amp outlet in when I do this for a 110v welder I am fixen to buy. I will run the 120v/20 amp outlet on a breaker by itself. I just don't know how I should do the rest of the outlets and the lights. I thought about putting the three 120v/15 amp outlets on a 15 amp breaker and the switch & outlet on another 15 amp breaker. Is this the way it should be done? When I wired the building I used 12-2 wired wich is rated for 20 amps, my outlets are rated at 15 amps, do I need to use a 15 or 20 amp breaker on these? Any advise would be helpfull. Thanks for the help.

01-28-2004, 08:53 PM

Were it I... I would have two circuits to the shed. 1 - 20A 120V for the welder and 1 - 20A 120V for the lights and receptacles. You can use 15A duplex receptacles. Make sure the receptacles are GFI protected. One GFI feed-thru receptacle will protect those receptacles. Use a separate GFI receptacle for the welder. If the welder has a 20A plug you will have to use a 20A recept. When in doubt, hire a pro.

benfranklinpa · 09-02-2005, 12:45 PM

just run a service enterance to the shed @ 240V 30A with #10AWG 3 conductor+ground UF wire and throw a sub-pannel in the shed. this will give you 2 120V 30A cuircuits or 2 120V 15A for lights and outlets, and 1 120V 30A for the welder. this would be the correct way to do it as you need to have a service disconnect at the external building. also you need to drive a ground rod at the external building ( shed) and bond it to your new sub-pannel and connect it to the ground wire from the feeder ( all grounds common) the only difference for the sub pannel is that the neutral does NOT get bonded to ground

sum up... feeder to shed with ground neutral and 2 hot wires
2 hots go to the 2 hots of the sub-pannel, neutral goes to the neutral bar of the sub pannel, ground from feeder goes to ground bar of the sub pannel, grounding rod gets wired to ground bar of the sub pannel. and the green screwor bonding screw for the neutral bar is NOT used (this connects or bonds the neutral bar to the grounded case of the subpannel)

if at anytime your running over 100 feet of wire you need to de-rate it, that is go up to the next highest guage ( 150 feet to shed at 30A would use a #8AWG)

Speedy Petey · 09-04-2005, 05:41 PM

Ben, I hope you do realize this post is more than a year and a half old. I would assume this project is completed.

Also, yes, in the situation you describe, a 4-wire feeder, the grounds and neutrals are not bonded. In the case of a 3-wire feeder though the grounds and neutrals DO get bonded. This point needs to be clarified.

Voltage drop is not dependent on distance only, and a feeder is not calculated at full amperage. You need to know the actual load or demand load in addition to the distance to make an accurate suggestion as to wire size and voltage drop. Of course bigger is usually not any worse other than cost wise.

I see in another thread you are an electrical novice. If you insist on giving electrical advice PLEASE be very certain any advice you give is well researched and documented. A disclaimer would not be a bad thing either.
There is WAY too much erroneous advice given over the web and electrical is no place for off the cuff advice.