Two Circuits Sharing Ground Circuit

[jyl]

Electricians -

I have a receptacle circuit in one room that is not grounded (because it is powered by an old lighting circuit - weirdness of 100 y/o house). I've put a GFCI receptacle in first position on that circuit, to get some protection.

When I add receptacles to the adjacent room, I'll be able to pull a ground wire from the adjacent room circuit to serve as the ground for this currently ungrounded circuit. I read NEC, it seems to permit two circuits to share the same ground conductor, if the circuits originate in the same enclosure, which these do.

So . . . sound ok?

[red 928]

When it comes to spark-tricity I'm no help at all, but what I can do is share this






PS seems to me if you install a combo GFCI/AFCI outlet, you would have all the bases covered.
With a grain of salt.

[jyl]

Is it better to do GFCI/AFCI protection at the breaker or at the receptacle?

[red 928]

A little voice is telling me that I've already over-commented on this subject because of my limited expert-tease.
But what does he know.

[masraum]

Originally Posted by jyl

Is it better to do GFCI/AFCI protection at the breaker or at the receptacle?

I'm not an electrician, and I am not a code expert.

I believe new/current code is that the protection should be at the breaker.

I assume that for practical purposes (protection of humans) as long as the GFCI works, it shouldn't matter which position it's in.

I don't know about the code-iness of having one ground for 2 circuits. It seems like it should work, and certainly be better than no ground.

I'm sure none of that really helps, but I'll be watching to see what the expert consensus is once it arrives.

[gacook]

Originally Posted by jyl

Electricians -

I have a receptacle circuit in one room that is not grounded (because it is powered by an old lighting circuit - weirdness of 100 y/o house). I've put a GFCI receptacle in first position on that circuit, to get some protection.

When I add receptacles to the adjacent room, I'll be able to pull a ground wire from the adjacent room circuit to serve as the ground for this currently ungrounded circuit. I read NEC, it seems to permit two circuits to share the same ground conductor, if the circuits originate in the same enclosure, which these do.

So . . . sound ok?

Sounds fine to me from a technical perspective; can't comment on code in your area. In my area, depends where the circuit is. GFCI is only "required" in the kitchen/bathrooms for us and in the kitchen, EVERY outlet has to be GFCI (stupid).

[BK911]

GFI's are touchy.
Definitely no shared neutrals.
Shared ground should be no big deal.

[Tidybuoy]

I am not an electrician, but I would think that sharing a ground would be ok. In a normal, modern electrical box, all of the circuits use the same ground bar.

I too have an old house that I just acquired. I have noticed that many of my electrical receptacles have a separate ground wire that is attached to a plumbing pipe. This is where the original wiring is knob and tube with no separate ground. I will slowly replace a lot of the wiring with romex as I have access to the main floor electrical from the basement and so this project won't be too difficult. The upstairs will be another issue.

[Bill Verburg]

All the grounds both white and bare are connected at the breaker box, the connection is the central strip between the 2 hot sides and bonded to the box and a rod in the ground

all the hots, black or red, are connected on one side or the other of the braker box

[Arizona_928]

Originally Posted by gacook

Sounds fine to me from a technical perspective; can't comment on code in your area. In my area, depends where the circuit is. GFCI is only "required" in the kitchen/bathrooms for us and in the kitchen, EVERY outlet has to be GFCI (stupid).

I concur.

Also the breaker box and therefore all circuits share the same ground bar.

[jyl]

Originally Posted by Tidybuoy

I am not an electrician, but I would think that sharing a ground would be ok. In a normal, modern electrical box, all of the circuits use the same ground bar.

I too have an old house that I just acquired. I have noticed that many of my electrical receptacles have a separate ground wire that is attached to a plumbing pipe. This is where the original wiring is knob and tube with no separate ground. I will slowly replace a lot of the wiring with romex as I have access to the main floor electrical from the basement and so this project won't be too difficult. The upstairs will be another issue.

Upstairs, running NM cable under the baseboards and receptacle boxes mounted behind openings in the baseboards makes it easy to wire outlets around a room - you just have to find one central place where you can run a bunch of NM cable up from basement to second floor - like a stairwell or something - and then from that central place run one cable to the nearest corner of each upstairs room. If baseboards are too small, well tall baseboards look better anyway. Don't go fishing cable through walls, any more than you have to. Abandon the old wiring in the walls. Get all new NM cable and all tied to the panel ground.

[jyl]

Man, GFCI breakers are expensive. CAFCI/GFCI breakers are really expensive. $50-100 a pop. That's like $2,000 just in breakers!

[look 171]

Around here, AFCI breakers will break the piggy bank. I cheat on my rentals. We install AFCI required for breakers throughout house but the kitchen. Just about all are GFCII there. AFter final inspection, out the AFCI and back in with the cheap typical breakers just like all houses had for the past 80 years. Yep, we create solutions to problems we do not have.

[look 171]

I don't know about code up there but it is OK here technically. GFI wouldn't work without a ground. It will trip

[fintstone]

Originally Posted by jyl

Electricians -

I have a receptacle circuit in one room that is not grounded (because it is powered by an old lighting circuit - weirdness of 100 y/o house). I've put a GFCI receptacle in first position on that circuit, to get some protection.

When I add receptacles to the adjacent room, I'll be able to pull a ground wire from the adjacent room circuit to serve as the ground for this currently ungrounded circuit. I read NEC, it seems to permit two circuits to share the same ground conductor, if the circuits originate in the same enclosure, which these do.

So . . . sound ok?

I would say that as long as both receptacles are the same 15A (not one 15 and one 25), you are ok, but if I were pulling a ground from the adjoining room, I would just pull the power from there as well while I was pulling wires (and disconnect it form the light), keeping outlets on the outlet circuits and lights on a lighting circuit. Then you can use the single GFCI to protect both circuits.

[Rapewta]

Your house shares the same ground throughout. It is not considered a current carrying conductor. The only time it does is during a momentary short. Hopefully the shorted breaker trips open.
The GFCI has to have the dedicated neutral (white) for it to work correctly.
Get on line and order the "Ugly"s" electrical references booklet. It is perfect for homeowners that want to safely do some simple electrical troubleshooting around the house. Keeps you out of trouble.
It is a small pocket book size.

[jyl]

Originally Posted by fintstone

I would say that as long as both receptacles are the same 15A (not one 15 and one 25), you are ok, but if I were pulling a ground from the adjoining room, I would just pull the power from there as well while I was pulling wires (and disconnect it form the light), keeping outlets on the outlet circuits and lights on a lighting circuit. Then you can use the single GFCI to protect both circuits.

That makes sense!

[zakthor]

I also have an old house with many two prong outlets. Solution when replacing those nasty outlets was a gfi at the first outlet in each room, this protects all the downstream outlets and code says all the 3 prong but groundless outlets need a sticker saying no ground but gfi.

In your case if I understand correctly you’ll be adding a ground wire to the gfi outlet, which I think means that one outlet can now live without the sticker.

I’ve read homeowners books about code and I’d put the ground on that gfi but I’d also like to know the answer from an actual expert. There’s some deep knowledge that went into the code and I love learning the whys.

[jyl]

Originally Posted by zakthor

I also have an old house with many two prong outlets. Solution when replacing those nasty outlets was a gfi at the first outlet in each room, this protects all the downstream outlets and code says all the 3 prong but groundless outlets need a sticker saying no ground but gfi.

In your case if I understand correctly you’ll be adding a ground wire to the gfi outlet, which I think means that one outlet can now live without the sticker.

I’ve read homeowners books about code and I’d put the ground on that gfi but I’d also like to know the answer from an actual expert. There’s some deep knowledge that went into the code and I love learning the whys.

Currently the room is like yours: no ground, GFCI in first position. Eventually I’ll ground the first receptacle, and all the subsequent receptacles have ground wires connected to the first.

Or, I’ll power and ground that room’s receptacles from the adjoining room.

Here is a table of the different circuit conditions and their risks.

[CurtEgerer]

Originally Posted by jyl

Man, GFCI breakers are expensive. CAFCI/GFCI breakers are really expensive. $50-100 a pop. That's like $2,000 just in breakers!

My brother has been making a small fortune for a few years re-selling new-in-the-box breakers on eBay he sources from Habitat, etc. The mains and obsolete stuff really bring crazy $$.