I have an enclosed porch on my house that appears to have been added sometime after the house was built in 1910. There's a live, but old and ungrounded receptacle out there that I wanted to change out to a GFI receptacle. I got the circuit shut off and pulled the receptacle out, inside the box there was a ground wire but tucked back in there and not hooked up. It was attached inside to the metal box. Look at how thin that is? The wiring appears to be maybe something from the 60's, it's a NM cable with a silvery outer sheath and the white and black wires appear to be 12 gauge but that crazy thin ground wire bothers me. Can I still use this for a GFI receptacle? I traced the run back to the panel and it's not long at all, maybe 12 to 15 feet.

The house has 200 amp service and a new really fat service connection out to the pole with a new panel, meter etc when we bought this place 3 years ago. There are the telltale signs of the original K&T wiring all over but that's all been removed. What I see running everywhere is maybe 50% of this NM with the silvery sheath and 50% brand new yellow 12-2 NM.

Am I ok to remove this old receptacle and put in a GFI one and use that thin ground wire?

Yes. It would be good if it's actually connected, but you could put a GFI in there even if it's not though.

Nothing wrong with that ground wire. And, from the sound of it, "connected to the box" your receptacle was picking up its ground from the ears contacting the box. The box was grounded.

You should be fine to replace that with a GFi outlet.

That said, I am not a licensed electrician but do much of my own household electrical fix/replace work.

Why would they make the ground wire such a smaller gauge in this old NM cable? I know the modern stuff is all the same gauge, right?

Yes. Some of the old stuff was manufactured in that fashion. Hell of a lot better than two wire. A lot of times I've seen those wires cut off or wrapped around a clamp screw with two wire receptacle installed. Like yours.

It is common (especially in larger wire sizes) to run the ground at least one size smaller than the hot and the neutral. Not an electrician, but I've seen electricians I respect do it and I've seen it on plans I got through the lead building inspector, so I assume it is to code.

quote:

Originally posted by PASig:
Why would they make the ground wire such a smaller gauge in this old NM cable? I know the modern stuff is all the same gauge, right?

Not necessarily. When I recently did some wiring, I used some 10/2, 8/2, and some 6/2. All of the ground wires were 10 gauge in those wires.

Well, it was all for nothing after all.

I got the GFI receptacle wired back up and tried to put in back the the box and it was so tight that the side screws were rubbing right onto the metal box sides. A big no-go.

I guess since this IS a covered porch I could get away with using a non-GFI receptacle but I didn't want to do that.

I think I'll just pull that cable out of there, it seems like it is it's own run and maybe re route it to the side of the house where I wanted to put an outdoor receptacle anyway.

I once lived in a house without the ground in the socket. Was a real pain. Adapters were supposed to ground to the center box screw, but they probably were not the safest either.

You could install a GFIC breaker.

I pulled the cable out and the outer sheath was really crumbly and fragile which makes me worry about all the rest of it in my house. I guess if I'm not screwing with it and it's just sitting, it should be ok theoretically?

I'll get help and run some new 12-2 right from the panel to a spot where I can take it outside which is what I wanted to accomplish anyway as a project.

For future reference , A GFCI receptacle does not need a ground wire to function . That small ground wire in your box was a non issue .

quote:

Originally posted by selogic:
For future reference , A GFCI receptacle does not need a ground wire to function . That small ground wire in your box was a non issue .

^^^ Absolutely true!

quote:

Originally posted by PASig:
I pulled the cable out and the outer sheath was really crumbly and fragile which makes me worry about all the rest of it in my house. I guess if I'm not screwing with it and it's just sitting, it should be ok theoretically?

I'll get help and run some new 12-2 right from the panel to a spot where I can take it outside which is what I wanted to accomplish anyway as a project.

You probably have what I call "rag wire" cloth wiring with tar and paint around it. It's fine, don't worry.

As selogic said a ground is not required in any way for a GFI to work. It measures the power going out on the hot and returning on the neutral. If that is off, even a tiny fraction then some of the neutral wire power is gong somewhere other than returning to the panel, and it will trip.

The ground only needs to be large enough to trip the circuit breaker incase of a hot/neutral fault, it was quite common in ragwire for it to be sized smaller than the conductors.

As far as the GFI touching the metal box, that is perfectly fine. The screws should be recessed in from the outlet so it's physically impossible for them to short to the box. Take the outlet out and put a straight edge against the plastic and verify for yourself this. If for some reason you got an oddball GFI that the screws would touch, then buy a different brand.

I have also made a wrap of tape around the receptacle to protect the screws from rubbing the sides of the metal box .

quote:

Originally posted by Skins2881:


You probably have what I call "rag wire" cloth wiring with tar and paint around it. It's fine, don't worry.

I think I have a couple pieces of that in my basement, it's black and pretty thick but the stuff I just pulled looks exactly like this (pic from internet) but the lettering on mine is green and it says "HATFLEX" I believe: