Equipment grounding wires outside of junction boxes

[marmathsen]

I'm a residential electrician in the Seattle and do a lot of remodels.

One thing I see a lot of is old work where the equipment grounding wires all come into the box with the old NM cable then are routed outside of the box and connected where it's inaccessible if the walls are all closed up. Why was this so common? What the the thinking in doing it this way?

This is almost always where the old cloth Romex with the undersized ground is used. I think typically 1950s or 60s.




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[infinity]

Same thing around here for stuff installed in the 60's. Not sure why but that is how they did back then.

 

[GerryB]

Same thing around here for stuff installed in the 60's. Not sure why but that is how they did back then.

View attachment 19871

That looks like it was done at a later time, I don't know. What I have seen is the old cloth romex ground wrapped around the the romex and making contact with the clamp. If you had two cables coming in the clamp and the box would be the bond between them, no actual splice.

 

[infinity]

That looks like it was done at a later time, I don't know. What I have seen is the old cloth romex ground wrapped around the the romex and making contact with the clamp. If you had two cables coming in the clamp and the box would be the bond between them, no actual splice.

The installation in the photo is from 1961 when the house was built. The AC cable was added later.

 

[marmathsen]

Same thing around here for stuff installed in the 60's. Not sure why but that is how they did back then.

View attachment 19871

This photo is exactly what I see all the time. Sometimes they used a crimp sleeve like in the photo, sometimes a wire nut.

I always imagined the thinking was something to the effect of...

"What the heck is with this new ground wire?! Why in the world would anybody want a bare wire inside the box with the hots?! I'm going to make this connection outside the box, that seems safest."

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[electrofelon]

Does anyone know the history of the equipment ground? Did people start using EGC's before it was required, or were there just few rules about installation practices or were they not enforced? One thing I never quite understood is I often see houses that have the same vintage NM, some have EGC and some dont. Was it originally only required on certain circuits?

 

[marmathsen]

Does anyone know the history of the equipment ground? Did people start using EGC's before it was required, or were there just few rules about installation practices or were they not enforced? One thing I never quite understood is I often see houses that have the same vintage NM, some have EGC and some dont. Was it originally only required on certain circuits?

I always assumed it was during a period of transition while they used up old ungrounded stock. But this is just speculation.

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[user 100]

Does anyone know the history of the equipment ground? Did people start using EGC's before it was required, or were there just few rules about installation practices or were they not enforced? One thing I never quite understood is I often see houses that have the same vintage NM, some have EGC and some dont. Was it originally only required on certain circuits?

Egcs were only required in certain areas in the 40's and 50's-----laundry (1947), kitchen (1956 I think), outside fixtures/receptacles (1956 or '59)..etc. So it really made no sense to connect the egc everywhere in a house or wire an entire house with the new fangled nm w/egc in jacket.

Egcs were also often ran separately along side 2w nm to metal boxes that were near plumbing-- one common practice was a light with a metal shell over a sink or receptacles next to the sink were grounded (egc either snaked its way back to the panel or was clamped to cw pipe---ntboad back then b/c all water pipe was metal), but a receptacle on an opposite wall in the same room wasn't.

It look cheesy and seems odd today, but it represents at least some concern for safety.....not exactly gfci, but certainly better than nothing: if a fault opened up the fixture over the sink, breaker tripped preventing electrocution. If no egc, and someone touched the fixture to change the bulb while touching the faucet that was connected to all that metal pipe......

 

[electrofelon]

Egcs were only required in certain areas in the 40's and 50's-----laundry (1947), kitchen (1956 I think), outside fixtures/receptacles (1956 or '59)..etc. So it really made no sense to connect the egc everywhere in a house or wire an entire house with the new fangled nm w/egc in jacket.

That makes sense. Now that I think about it, if I see a mix, it is usually the general use #14 that do not have an EGC.

Egcs were also often ran separately along side 2w nm to metal boxes that were near plumbing-- one common practice was a light with a metal shell over a sink or receptacles next to the sink were grounded (egc either snaked its way back to the panel or was clamped to cw pipe---ntboad back then b/c all water pipe was metal), but a receptacle on an opposite wall in the same room wasn't.

It look cheesy and seems odd today, but it represents at least some concern for safety.....not exactly gfci, but certainly better than nothing: if a fault opened up the fixture over the sink, breaker tripped preventing electrocution. If no egc, and someone touched the fixture to change the bulb while touching the faucet that was connected to all that metal pipe......

Ok good to know. I see that fairly often. I was never quite sure if the external grounds were something someone did later .

 

[marmathsen]

Egcs were only required in certain areas in the 40's and 50's-----laundry (1947), kitchen (1956 I think), outside fixtures/receptacles (1956 or '59)..etc. So it really made no sense to connect the egc everywhere in a house or wire an entire house with the new fangled nm w/egc in jacket.

Egcs were also often ran separately along side 2w nm to metal boxes that were near plumbing-- one common practice was a light with a metal shell over a sink or receptacles next to the sink were grounded (egc either snaked its way back to the panel or was clamped to cw pipe---ntboad back then b/c all water pipe was metal), but a receptacle on an opposite wall in the same room wasn't.

It look cheesy and seems odd today, but it represents at least some concern for safety.....not exactly gfci, but certainly better than nothing: if a fault opened up the fixture over the sink, breaker tripped preventing electrocution. If no egc, and someone touched the fixture to change the bulb while touching the faucet that was connected to all that metal pipe......

Very useful! Thanks!

Do you also know why the EGC was often connected outside the j-box?

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[user 100]

Very useful! Thanks!

Do you also know why the EGC was often connected outside the j-box?

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If I had to make a wild guess, the *only* thing I can think of is maybe they did it that way to have a little more room inside the box??

I say that b/c if you were to include (terminate/deadend) the egc(s) inside that particular box size in infinity's pic, and then you throw in the H & N's from multiple cables, then the device, and any needed joints, its gonna get a little tight.

 

[kwired]

If I had to make a wild guess, the *only* thing I can think of is maybe they did it that way to have a little more room inside the box??

I say that b/c if you were to include (terminate/deadend) the egc(s) inside that particular box size in infinity's pic, and then you throw in the H & N's from multiple cables, then the device, and any needed joints, its gonna get a little tight.

That box appears to be new enough it has threaded holes for bonding screws. Most the old boxes I ever run into that were made before EGC's were commonly used never had threaded holes in them for bonding screws.

Just an observation, don't know that it means anything for that installation.

 

[user 100]

That box appears to be new enough it has threaded holes for bonding screws. Most the old boxes I ever run into that were made before EGC's were commonly used never had threaded holes in them for bonding screws. .

^^^^
This too :thumbsup:

That also makes sense---you're right---many of those old boxes (old BMC is notorious for this) don't have the threaded hole for terminating inside the box. Ofc they could have relied on one of the clamp screws for inside the box termination, but if both clamps (like in infinity's pic) were being utilized that idea was out. So in order to connect the egc to the box, they HAD to terminate outside the enclosure. And even if the box did have the holes, they were so used to doing it the one way, the holes were ignored.

Gentlemen, I believe we have a winner----Kwired has solved the age old question of "why" the Boston backwrap!!

 

[MTW]

In the early forties, here in the Detroit area. Boxes near sinks and washing machines were required to be grounded by running a bare conductor to the local cold water pipe supplying the sink. If there were more than one box to be connected, the EGC was spliced behind the box and extended over, so only one pipe clamp was used. Bare Buchannan splice caps were the device used to splice the pigtails. The boxes has no tapped hole for a ground screw, so the clamp screws were used to connect a pigtail to. There were no devices that required a GEC connection, so the the GEC pigtail only entered the the box, to ground the box and make it accessible.

At the service fuse box, a bonding jumper was run from the neutral bar to the nearest available cold water line. No ground rods were used.

A 1940's bracket box, without the tapped holes, and before galvanizing was the norm. The cable was always 2 wire, each cloth covered conductor radially wrapped with paper, then an outer cloth sheath, impregnated with asphaltic compound.

MTW