Electrical Question

[obanion]

I know the basics on residential wiring, and have done various indoor wiring projects, but I have a question for you regarding an outdoor project. I want to install a 30 amp 110V receptacle for an RV. I purchased a receptacle that is already mounted inside of a metal box. I am planning on mounting it to a metal shed. The receptacle will be on its own 30 amp circuit on 10# wire. From the factory, the receptacle is grounded to the metal box by a wire from the grounding terminal on the receptacle to a terminal mounted on the box. If the receptacle is grounded to the metal box, how should I ground the box? If I were to remove this wire and connect the receptacle to the grounding wire going back to my service panel, the box would not be grounded. Would this be safe? Any advice that anyone could give me would be much appreciated.

[I-zheet M'drurz]

This is a tough call, on whether to answer this one or not. It's a super simple answer to anyone with the experience you've described, so you -may- be blowing some smoke up our butts about your knowledge level.

BUT...I'll give you the benefit of the doubt and just assume you're putting -way- too much thought into it, and overlooking the obvious. Here ya go...

The "terminal mounted on the box" -- is there room to put -two- wires in the "terminal"? Or is it simply the wire wrapped around a screw?

If there's room for two conductors, that's your answer. Loosen the screw, slide your new ground wire in next to the existing one, and tighten it down again.

If not, simply remove that wire from the box terminal and pigtail it with your incoming ground conductor and a short jumper that you'll make. your jumper goes to the terminal on the box, and all 3 ground wires get twisted together and wire nutted.

[Joe]

[obanion]

Thanks for your help. I had thought about that but wasn't sure if that was the right thing to do. The wire connected to the terminal on the recepticle actually has a flat connector on it...i should be able to secure a wire on top of that under the screw...thank you very much for your help

[Joseph Meehan]

DON'T use pipes for electrical ground!

[Joseph Meehan]

As I-z suggested, your supply line should supply an electrical ground (in this case it is very important that it does) and that should be tied to your new box/outlet.

I suggest that since this is a metal building you isolate the box from the building and/or provide a separate electrical ground for the building. I don't know what the code calls for, but I don't like the idea of a failure possibly creating a whole hot building.