I am running some wire in my garage for an outdoor receptacle. From the replies I received to a previous post, I determined that the best way to handle this project was to run my 12/2 Romex to a junction box, then to run THHN down a metal conduit (since I wanted to protect the wires) through my garage wall to the outdoor box holding my receptacle.

My current question is how to properly handle the grounding here. Do I...:

1. ...just connect the ground wire from the 12/2 ground wire to the junction box, as that will be sufficient to ground the conduit, outdoor box and receptacle since they are all connected with no gaps?

Or,

2. ...connect the 12/2 to the junction box, then connect a separate ground wire to the 12/2 ground wire and run the new ground wire down the conduit and connect that ground wire to the outdoor box and receptacle? If I need to use this scenario, can I use a bare wire that is contained in a spare piece of Romex, or do I need to use another piece of THHN (green insulation)?

I thought I could be OK with scenario 1, but I wanted to make sure before I continue.

Thanks,
Guy

 

#1 is okay with one addition. You need to add a grounding pigtail from a ground screw in the outdoor box to the outdoor receptacle. Simply mounting it to the metal box is not an acceptable ground.

You can also install a separate ground wire in the conduit if you choose. Bare wire stripped from romex is okay.

My personal policy is to only use the conduit as a ground if you use compression fittings. The set screw fittings can come loose and rust over time weakening the ground path.

 

SS fittings are not listed for outside use are they ibpooks? Actually basic compression fittings aren't either. They need to be listed for raintight applications. There is a difference.

 

If your outside box is a surface mount box, you won't need to ground (bond) the box if at least one of the insulating washers from your receptacle (the washers that holds the screws in) is removed. 250.146(A)

 

Thanks for all replies.

[QUOTE=wirenut1110;1481337]If your outside box is a surface mount box...QUOTE]

My box is not surface mount; it is cut a rectangular hole in some brick. The back of the in-use cover is flush with the face of the brick.

 

No, you're right. I didn't make the connection that the outdoor receptacle was actually outside.

 

But if the box is not surface mounted, why would it be considered outside?