Correct Use of Self-Grounding Outlets?

[908Jim]

Old 1940's house owner here, located in NJ and I think still on 2020 NEC, and not an electrician. Most of my home has modern NM-B but there are still 4 remaining circuits with original BX wiring. These will all be replaced over the next few years but this room needs some ugly and worn out receptacles replaced today. None of the original Appleton branded metal boxes have threaded grounding holes in them, and the outlets installed when we bought the home were three prongs just left ungrounded. In all the old single gang boxes, I used grounding clips for a ground lead but I am down to one 4x4 box with a mud ring. This means I can't slip these ground clips over the edge of the box. I have read you can drill and thread a hole but I don't know if I will get enough thread engagement and I didn't think you were allowed to modify listed boxes. These also appear to be painted black inside.

My question is: Can I use a self grounding outlet if the box is recessed past the plaster skim coat? This would mean the back of the outlet does not make contact with the metal box and the yolk mounting screw in contact with the brass self grounding spring clip thing is the only ground path back to the metal box. I was under the impression the brass was supposed to be making contact with metal but maybe I am misunderstanding the correct use. This seems better than the current state of free-floating receptacle with no ground, but I don't know if it is the correct application or if I have other options.

My other option is swapping to a GFCI/AFCI breaker I guess?

I would appreciate the help to make sure this is safe. Thank you.

 

[Firebrick43]

Self grounding outlets "MUST" have the yoke to touch the box/mud ring mounting flanges. 250.146(A), If not you need a separate bonding conductor is needed.

The mud ring/cover has to be flat as well where it mounts to the box with screws, no raised mounting areas.

You can add a ground screw as long as the box is thick enough to satisfy 250.8

"(6) Thread-forming machine screws that engage at least two threads in the enclosure"

So if the metal is 1/16th or thicker the self tapping green ground screws will work. All the old receptacle boxes I have seen usually are that thick.

Cheap metal enclosures are usually to thin to add grounding screws directly and need nuts.

 

[Chuckster in NJ]

Old 1940's house owner here, located in NJ and I think still on 2020 NEC, and not an electrician.

Good info on post #2.
FYI: NJ has adopted the the 2023 NEC on 8-17-26 and in your situation it doesn’t affect you.

 

[theoldwizard1]

My other option is swapping to a GFCI/AFCI breaker I guess?

A GFCI receptacle can be used on any old 2 wire circuit and protect the outlet. Anything downstream would also be protected.

 

[mm08822]

Self grounding outlets "MUST" have the yoke to touch the box/mud ring mounting flanges. 250.146(A), If not you need a separate bonding conductor is needed.

The mud ring/cover has to be flat as well where it mounts to the box with screws, no raised mounting areas.

You can add a ground screw as long as the box is thick enough to satisfy 250.8

"(6) Thread-forming machine screws that engage at least two threads in the enclosure"

So if the metal is 1/16th or thicker the self tapping green ground screws will work. All the old receptacle boxes I have seen usually are that thick.

Cheap metal enclosures are usually to thin to add grounding screws directly and need nuts.

Not so. The supporting screws on the receptacle (specifically the one with the spring clip) is considered making the ground connection to the metal box whether or not the receptacle ears touch the box. 250.146(B).

Non-self grounding recepts can be used with direct metal to metal contact between yoke and box/mud ring typical of surface mounted boxes/covers/mudrings. (That is what 250.146(A) states.)

 

[mm08822]

FYI: NJ has adopted the the 2023 NEC on 8-17-26 and in your situation it doesn’t affect you.

And I just went to the requried Code update class this past weekend for the 2026 revs.

Time for the 2023 refresher class.....8 hours is 8 hours!

 

[908Jim]

Self grounding outlets "MUST" have the yoke to touch the box/mud ring mounting flanges. 250.146(A), If not you need a separate bonding conductor is needed.

The mud ring/cover has to be flat as well where it mounts to the box with screws, no raised mounting areas.

You can add a ground screw as long as the box is thick enough to satisfy 250.8

"(6) Thread-forming machine screws that engage at least two threads in the enclosure"

So if the metal is 1/16th or thicker the self tapping green ground screws will work. All the old receptacle boxes I have seen usually are that thick.

Cheap metal enclosures are usually to thin to add grounding screws directly and need nuts.

Thanks! I can't find thread forming machine screws (that are green) locally. My HD only sells the regular green non-threading ones. I did look up 250.8 and notice it says "(5) Machine screw-type fasteners that engage not less than two threads ..." and now I'm wondering if this means I can drill and tap the box, or if this requires an existing hole.

Good info on post #2.
FYI: NJ has adopted the the 2023 NEC on 8-17-26 and in your situation it doesn’t affect you.

Good to know! Thank you!

A GFCI receptacle can be used on any old 2 wire circuit and protect the outlet. Anything downstream would also be protected.

Agreed, but I avoid that in this house because the old circuits make no sense. Maybe it was a war time shortage, but the house looks like it was wired to minimize wiring, not to be logical. This living room receptacle in question feeds the dining room chandelier and the light in one of the bedroom closets. I know this, but I cannot imagine somebody else trying to hunt down a tripped GFCI in the living room because the bedroom closet light isn't working. Plus the GFCI in the living room wouldn't look great.

Not so. The supporting screws on the receptacle (specifically the one with the spring clip) is considered making the ground connection to the metal box whether or not the receptacle ears touch the box. 250.146(B).

Non-self grounding recepts can be used with direct metal to metal contact between yoke and box/mud ring typical of surface mounted boxes/covers/mudrings. (That is what 250.146(A) states.)

I wasn't aware of this section but I read 250.146 and I think the discrepancy between the advice of @mm08822 and @Firebrick43 comes down to the distinction between the code for surface mount and flush mount boxes. As Firebrick states, I wasn't aware that I could use regular (not self-grounding) outlets on surface mount metal boxes without a wired ground. Because flush mount boxes are permitted to be up to 1/4" recessed behind the drywall surface per 314.20, I don't see how 250.146(B) could possibly allow self-grounding outlets unless the assumption was that the ground path was through the screw itself.

After reading this thread and the codes few times, I am more comfortable and think it is compliant to use the self-grounding outlet with a slightly recessed flush mount box. I appreciate the help!

 

[theoldwizard1]

A GFCI receptacle can be used on any old 2 wire circuit and protect the outlet. Anything downstream would also be protected.

Agreed, but I avoid that in this house because the old circuits make no sense. Maybe it was a war time shortage, but the house looks like it was wired to minimize wiring, not to be logical.

My daughter's first house was built in 1946, so right after the war. Same stupid kind of wiring. 2 entrances to the kitchen, one light switch ! Kitchen circuit shared with other rooms. Thankfully, they install a modern breaker panel when they installed the A/C in the early 1990s !

During the kitchen remodel, I added 4 circuits for the kitchen. Of course the ones on the countertop were GFCI. There wer 2 other locations were I install GFCIs on the old 2 wire circuits. In both case it was so that 3 wire power strips (for low current electronics) could be plugged in directly.

 

[908Jim]

My daughter's first house was built in 1946, so right after the war. Same stupid kind of wiring. 2 entrances to the kitchen, one light switch ! Kitchen circuit shared with other rooms. Thankfully, they install a modern breaker panel when they installed the A/C in the early 1990s !

During the kitchen remodel, I added 4 circuits for the kitchen. Of course the ones on the countertop were GFCI. There wer 2 other locations were I install GFCIs on the old 2 wire circuits. In both case it was so that 3 wire power strips (for low current electronics) could be plugged in directly.

Same story here. I had the panel and service upgraded when we moved in a few years ago and a kitchen and first bathroom renovation and an addition in the 20teens brought all modern wiring and several dedicated circuits to much of the first floor. HVAC, Laundry, exterior and Sump Pump is all modern. The 2nd floor main bath was also previously renovated but the bedrooms still have a mix of modern NM-B old work and a few circuits that still have original wiring.

I am going to pull a permit in the next few weeks to redo basement lighting and will replace a few NM (not -b) and BX circuits then as well. Little by little!

 

[whateg01]

Agreed, but I avoid that in this house because the old circuits make no sense. Maybe it was a war time shortage, but the house looks like it was wired to minimize wiring, not to be logical. This living room receptacle in question feeds the dining room chandelier and the light in one of the bedroom closets. I know this, but I cannot imagine somebody else trying to hunt down a tripped GFCI in the living room because the bedroom closet light isn't working.

Label ****! Put a diagram in the breaker box!

Plus the GFCI in the living room wouldn't look great.

Well as long as it looks good who cares what works and what doesn't, right?

 

[908Jim]

Label ****! Put a diagram in the breaker box!

The labeling was so insane I actually made a full floor plan and labeled every switch, light, receptacle etc with specific circuit numbers.

Well as long as it looks good who cares what works and what doesn't, right?

My point was that I can add the same GFCI protection at the panel and accomplish exactly the same thing while keeping the location of the reset exactly where a person would start to look if they had a problem, rather than somewhere random in the house.

 

[dave*99]

My point was that I can add the same GFCI protection at the panel and accomplish exactly the same thing while keeping the location of the reset exactly where a person would start to look if they had a problem, rather than somewhere random in the house.

Interesting concept. I usually get "Oh yeah, that receptacle hasn't worked for weeks, I forgot to tell you." Nobody here looks... And of course this is mentioned when I'm nowhere near to place and can't look easily.

 

[theoldwizard1]

I am going to pull a permit in the next few weeks to redo basement lighting and will replace a few NM (not -b) and BX circuits then as well. Little by little!

You do know, that the inspector may decide to inspect ALL of the wiring in the house !

 

[theoldwizard1]

Plus the GFCI in the living room wouldn't look great.

Well as long as it looks good who cares what works and what doesn't, right?

The one I installed in my daughter's house was under/behind a cabinet.

 

[908Jim]

You do know, that the inspector may decide to inspect ALL of the wiring in the house !

All work we had done is permitted and all work to be performed is going on the permit. The minimum permit charge doesn't really incentivize doing unpermitted work.

 

[mm08822]

All work we had done is permitted and all work to be performed is going on the permit. The minimum permit charge doesn't really incentivize doing unpermitted work.

While the inspector may comment on the condition/safety of "other things" observed, it's not within his scope/authority to challenge original as-built and prior inspected work. Unpermitted work observed can be another situation.

What part of 908?

 

[sparky 1971]

You do know, that the inspector may decide to inspect ALL of the wiring in the house !

Nope.

 

[dscheidt]

While the inspector may comment on the condition/safety of "other things" observed, it's not within his scope/authority to challenge original as-built and prior inspected work. Unpermitted work observed can be another situation.

What part of 908?

There's local variation in that. Inspectors aren't likely to go out of their way to find something, but if they see something unsafe or clearly not allowed, in many places they can require it to be fixed.

Thanks! I can't find thread forming machine screws (that are green) locally. My HD only sells the regular green non-threading ones. I did look up 250.8 and notice it says "(5) Machine screw-type fasteners that engage not less than two threads ..." and now I'm wondering if this means I can drill and tap the box, or if this requires an existing hole.

you can drill and tap 10-32, or drill and use a thread forming 10-32-tpi screw. It doesn't need to be green. Modern boxes have the ground hole (which often isn't threaded, because thread forming screws give better contact, and, bonus, it's cheaper not to) on a raised bump, because that ensures there's clearance for the screw to stick past the box.

I wasn't aware of this section but I read 250.146 and I think the discrepancy between the advice of @mm08822 and @Firebrick43 comes down to the distinction between the code for surface mount and flush mount boxes. As Firebrick states, I wasn't aware that I could use regular (not self-grounding) outlets on surface mount metal boxes without a wired ground. Because flush mount boxes are permitted to be up to 1/4" recessed behind the drywall surface per 314.20, I don't see how 250.146(B) could possibly allow self-grounding outlets unless the assumption was that the ground path was through the screw itself.

After reading this thread and the codes few times, I am more comfortable and think it is compliant to use the self-grounding outlet with a slightly recessed flush mount box. I appreciate the help!

A listed self-grounding device has spring-loaded brass contact that presses against the screw, and forces the screw to be in contact with the other side of the yoke. That ensures continuous contact between the device yoke, which is connected to the device goround, and the screw, and because the screw is screwed into the box or mud ring (which is screwed to the box...) with those not less than two threads, there's a ground path from the device to the box. Remember, the only time there's current on the ground is when there's a fault, and that only lasts until the OCPD trips, which for a dead short should be really damn fast, there is not much energy in the fault, so the screw threads are good enough contact. (It's also a bigger contact area than you might think.)

 

[mm08822]

There's local variation in that. Inspectors aren't likely to go out of their way to find something, but if they see something unsafe or clearly not allowed, in many places they can require it to be fixed.

I believe it gets accomplished in one of a few ways......each way increasingly more painful.

1) Comment to owner and/or contractor that x needs to be fixed. (It's the owner's problem not the contractor who contracted/permitted for separate unrelated scope of work.) This could be a milestone to get a CoA.
2) Provide written communication to owner with notice the structure will be condemned if x not fixed and a permit taken out for inspection of proper fix within # of days. If it becomes condemned, then a CoA is required for re-use or re-occupancy. Fines, etc can be imposed if use continues or re-use resumes w/o inspection/CoA.
3) Immediately condemn the structure if eminent failure/collapse/explosion, etc. with coordination from the relevant construction office. Then that puts the owner back into #2 above.

Passing the contractor's unrelated permitted work should not become a hostage for inspection approval against that permit. It's the owner's separate problem. A CoA maybe gets held up, but the contractor is clear of that problem. The (electrical) contractor's responsibility/obligation usually ends once the electrical permit inspection is passed. (A fire inspection is likely required for smokes installed by the sparky.)

The inspector is also not allowed to conduct a full on cavity search in areas unrelated to the permitted work, e.g. - cant tour the 2nd floor, attic and garage when all the permitted work in scope is only in the basement.

 

[Chuckster in NJ]

Simple! I did inspections on work that was ONLY on the tech section (permit) unless I saw a potentially hazardous situation that needed to be addressed with the owner.
EG: I go out to a job that has a permit for a generator install and I see a "in ground pool" without a barrier so I would talk to the owner about it and tell them they need to install a barrier around the pool and I will be sending a "Notice of Violation" for this violation (CYA) and it must be addressed within two weeks or the penalties will start building up…….. Most folks complied and "did the right thing" and a few would totally ignore the violation and at that point I would take them to municipal court after 30 days.
Basically, the State of NJ tells us that you are there to look ONLY at the work being inspected unless you see a true life safety violation and "IF" you are that type of "rogue/nazi code official" that does a tour of the house you will be spanked really hard for over stepping your boundaries inspecting previously installed work.…… My days were so busy I didn’t have time to "create" work for myself.

BTW! God forbid you had a fire or accident (deck collapse, grow operation, etc) at the property and I was called out to find out what was going on because the fire or police department noticed some visible violations at the property, only then I would start going through the house to see what else was wrong.
EG: Had a landscaper fall through à pool cover with a back pack blower on and he drowned so I got called out only to find a pool without a barrier and the owners defense was he had a cover that was advertised to hold the weight of an elephant.…… Owner had other violations on the property that he was cited for.
Had a few other properties where the owners got popped on a pot grow project and those houses had all sorts of violations.