I'm trying to add an outlet at my wife's business. Usually I don't have any issues with small jobs like this. I was having trouble finding a place to tap power from. I decided on an outlet on an opposite wall where I can run wire in an unused utility closet.

Long story short is that I found the outlet I'm tapping from has 3 prong but the ground wire is only attached to the metal box. I don't see any wire grounding the box to anything. I need a 3 prong outlet where I'm putting the new outlet. I've already actually run the wire through the walls to the old outlet when I found the issue with only grounding to the box. My new work box is plastic. Is there anything I can do to easily get the new outlet safely connected? I already have to put another metal box in the closet and to make my connections because there simply isn't enough wire length in the old outlet box to make my connections.

So you have two wires (hot, neutral) coming into the box, no ground? And then a jumper from the green screw on the outlet going to the box?

You need one of these.



They are using self grounding outlets likely or it's old construction. Just need a pigtail to attach to the outlet. If it's really old wire "BX" then there is no ground and the jacket to the cable is the ground.

Edit. I just re-read that. So you are using Romex in a commercial location? Can only be done with construction under 4 levels tall first off, second off it's not a best practice in commercial.

It is legal to do under four stories with certain types of construction, not dropped ceilings.

If this is commercial building your likely looking at BX without a ground. The jacket of the BX is the ground.

It may not be legal to use Romex or plastic boxes if it is commercial construction.

edited I think Skin covered it while I was typing.

No idea what be is. I'm using cable in metal conduit. What I bought looks like what is in the building. It's 20 amp so I got 12 gauge wire. My wire has black/white and green. The existing has no ground wire. The existing outlet has a piece of copper wire from the outlet green screw to the screw on the metal box. I can go grab a metal box for my new outlet. Just not sure what to do about ground. Also no idea what that picture above is. Also not sure what a self grounding outlet is.

I've read I can put a gfci outlet in if it's labeled no ground.

quote:

...the ground wire is only attached to the metal box. I don't see any wire grounding the box to anything.

I think this statement appears contradictory and confusing. Is the box grounded and the outlet isn't, or vice versa? What Skins2881 has posted is a pigtail to screw into a metal outlet box so that it can be grounded. You'd include it, along with another pigtail to the outlet, and wire them together with the ground wire coming into the box.

Skins2881, wasn't the height restrictions on NM removed in the more recent NEC, and type NM use now depends on building construction type and use? Of course that doesn't mean local building codes still don't maintain the restriction, I guess. I suppose it's just better to use MC and not have to worry about it.

The building must be an older one that uses BX, as comet and I said the jacket is the ground there. You can not use a plastic box for MC wire (the type you are using).

Click on the link I provided with the picture. It's a piece of ground wire that has a ground screw attached, you can easily make the same with a ground screw and a piece of scrap green wire.

On the old side attach the new green wire to the box using a ground screw. On the new outlet side attach the pigtail to the metal box. Attach that pig tail to the new ground wire and a short piece of ground coming from the outlet, wire nut those three wires together. This grounds the box and outlet.

quote:

Originally posted by sigcrazy7:

quote:

...the ground wire is only attached to the metal box. I don't see any wire grounding the box to anything.

I think this statement appears contradictory and confusing. Is the box grounded and the outlet isn't, or vice versa? What Skins2881 has posted is a pigtail to screw into a metal outlet box so that it can be grounded. You'd include it, along with another pigtail to the outlet, and wire them together with the ground wire coming into the box.

Skins2881, wasn't the height restrictions on NM removed in the more recent NEC, and type NM use now depends on building construction type and use? Of course that doesn't mean local building codes still don't maintain the restriction, I guess. I suppose it's just better to use MC and not have to worry about it.

We were typing at the same time. I don't really know if they got rid of the height, it doesn't matter anyways because as you said before it was height combined with type of construction. I go with matching what is already there. If no wiring exists and unless the building looks like a house, stick built with drywall then I use MC.

In the old box the outlet green screw is connected to the box green screw. Not trying to sound contradictory. I thought the green had to go to ground somewhere and just connecting to the box wasn't really grounded.

Again I'm not sure what BX is. Does the metal conduit the wire is inside somehow act as a ground? Sounds like I can just run the new outlet from the old and use a metal box.

ETA: I don't know that I need a pigtail screw unless new metal box doesn't have a ground screw. I'd just need some extra wire.

The BX/AC (existing wire type) grounds the box through the connector's connection to the outer jacket of cable.

The new wire MC has a ground wire in it, that is your ground for the new outlet. The wire becomes grounded by the box of the old outlet via a ground screw.

The new outlet is grounded with the green wire being attached to the metal box and outlet using a pigtail.

The pigtail does not have to be a premade one, you can make your own using a ground screw and scrap wire. You really just need two ground screws.

Also make sure to use MC connectors and redeyes to install the wires at both boxes, don't just put the wire through the knock out. No plastic boxes allowed.

BX is wire inside a flexible metal conduit.

The metal sheathing on BX is the ground in older buildings. There was no green/ground wire. The BX is connected to the metal box making the box itself a ground. The outlet is grounded to the metal box with the screws you use to attach the outlet to the box.

quote:

Originally posted by comet24:
BX is wire inside a flexible metal conduit.

The metal sheathing on BX is the ground in older buildings. There was no green/ground wire. The BX is connected to the metal box making the box itself a ground. The outlet is grounded to the metal box with the screws you use to attach the outlet to the box .

Only if you use a self grounding outlet. I still always connect the outlet to the box with ground screw and wire scraps when I change one.

Okay now I understand Bx I was trying to use some old conduit and a thin part of the metal was wrapped tightly around the wire. So now I assume that was what is running as ground. So I think I know what to do. Gotta go get a metal box and a few things.

quote:

Originally posted by comet24:
BX is wire inside a flexible metal conduit.

The metal sheathing on BX is the ground in older buildings. There was no green/ground wire. The BX is connected to the metal box making the box itself a ground. The outlet is grounded to the metal box with the screws you use to attach the outlet to the box.

Thanks everyone. This is what I needed to know to do the job. I was thinking there was no ground in the existing wire. I've completed the job with metal boxes and wired the ground wires. I ended up buying the grounding wire pigtails as they made things easier and the new metal box needed it as it didn't come with a grounding screw.