Inspector said we need to ground existing metal boxes

Stevenfyeager

Senior Member
Location
United States, Indiana
Occupation
electrical contractor
Older two wire nonmetallic cable house we did some work in had metal boxes. Inspector said we need to ground those existing boxes. How does one do that without rewiring the whole house ?
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
I would use a saw zall and cut the nails holding the boxes, then replace with plastic old work boxes
 

Stevenfyeager

Senior Member
Location
United States, Indiana
Occupation
electrical contractor
You don't. You ask for the justification for such a ridiculous expectation.

If it was compliant when it was installed, it may remain under most conditions.

If it's a home inspector, you ignore him.
Thank you. I was too thinking that if it was compliant when the house was built, then we don't have to do anything. I just now realized I need to check something though. When my guys changed two hole outlets gfci outlets, would that require me to do something since they "tampered" with the existing outlets? I will check tomorrow. That could be what the inspector meant. (I couldn't be there for inspection)
Thank you.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
See 250.130 (C), I use that one often, for things like a fridge or freezer that 250.114 requires a ECG for and the 'no equipment ground ' GFCI exception in 406.4(D) wont suffice.
 
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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
When my guys changed two hole outlets gfci outlets, would that require me to do something since they "tampered" with the existing outlets?
No. If anything, you made the installation safer.

He may be mistakenly trying to test them with a plug-in GFCI tester, which requires an intact EGC pathway.

Neither the GFCI receptacles nor those downstream will respond to a plug-in tester.
 
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hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
When my guys changed two hole outlets gfci outlets, would that require me to do something since they "tampered" with the existing outlets? I will check tomorrow. That could be what the inspector meant.
So, let's see. You change the two prong receptacles out to GFCIs because there is no EG available. Now an inspector want's you to provide an EG for all the boxes. o_O

-Hal
 

suemarkp

Senior Member
Location
Kent, WA
Occupation
Retired Engineer
Thank you. I was too thinking that if it was compliant when the house was built, then we don't have to do anything. I just now realized I need to check something though. When my guys changed two hole outlets gfci outlets, would that require me to do something since they "tampered" with the existing outlets? I will check tomorrow. That could be what the inspector meant. (I couldn't be there for inspection)
Thank you.
Changing out a receptacle, however, can cause AFCI, GFCI, and TR rules to kick in. See 406.4(D)(1) - (8).
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
So, let's see. You change the two prong receptacles out to GFCIs because there is no EG available. Now an inspector want's you to provide an EG for all the boxes. o_O

-Hal
Is he looking at there is no bonding wire from the receptacle to the ungrounded metal box? Not sure that is even an issue. But no requirement to run an EGC from the source to the metal box if you are providing a GFCI on a replacement to an ungrounded old installation.
 

kwired

Electron manager
Location
NE Nebraska
Changing out a receptacle, however, can cause AFCI, GFCI, and TR rules to kick in. See 406.4(D)(1) - (8).
But nothing there would address whether he needs to bond the existing device box.

If anything you possibly may run into an old box without enough volume to install your GFCI, should you replace it with a metal box now maybe it gets more complicated as to whether you must bond that box to an EGC but leaving an existing metal box unbonded is ok?

I've used non metallic wiremold extension boxes before when doing something like that to solve box volume issues as well as not disturb plaster walls in attempt to replace the existing box. Maybe it is not compliant? Likely not required to be inspected when I have done it either making me essentially the AHJ in that situation.
 

suemarkp

Senior Member
Location
Kent, WA
Occupation
Retired Engineer
But nothing there would address whether he needs to bond the existing device box.
True. I was picking up the OPs comment of "When my guys changed two hole outlets gfci outlets, would that require me to do something since they "tampered" with the existing outlets?"

So yes, he has some things to do because he replaced the receptacle. But I agree that grounding the box isn't one of them unless maybe 250.114 requires it.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
But nothing there would address whether he needs to bond the existing device box.
Depends where the receptacle is, years ago when I first got hit by 250.114 it was when I changed a 2-prong receptacle to a 'no equipment ground' GFCI at a built in computer desk aka "information technology equipment".
The second time it was old kitchen 'reface' that had a counter top & back splash being updated, I tried the 'no equipment ground' inspector thought 250.114 applied because your likely to use "Hand-held motor-operated tools" on a kitchen counter top and the fridge.
Pulling the old metal boxes would have disturbed the new tile so I did 250.130(C)
Anything outdoors is also a no-go
 

kwired

Electron manager
Location
NE Nebraska
Depends where the receptacle is, years ago when I first got hit by 250.114 it was when I changed a 2-prong receptacle to a 'no equipment ground' GFCI at a built in computer desk aka "information technology equipment".
The second time it was old kitchen 'reface' that had a counter top & back splash being updated, I tried the 'no equipment ground' inspector thought 250.114 applied because your likely to use "Hand-held motor-operated tools" on a kitchen counter top and the fridge.
Pulling the old metal boxes would have disturbed the new tile so I did 250.130(C)
Anything outdoors is also a no-go
without additional local rules, I think the refrigerator is only one of your cases where it would be justified by NEC alone to reject those. You can't "what if" this or else you would end up "what iffing" all possibilities away.
 

garbo

Senior Member
Side note: Years ago you were allowed to run a ground wire to a metal box but thought that I read a few years ago that is no longer allowed. Believe article or person stated that if you are able to install a ground wire would be safer to pull in a new NMB cable to replace the NM cable without a ground wire that they stopped manufacturing in the mid 1950's. My parents house was built in the 1950's and had the 14/2 NM cable with a # 16 ground wire. Houses across the street were built a year later with 14/2 NM cable that did not have a ground wire. When my house was built they ran one 14/2 NM with the flimsy #16 guage ground to bottom of a wall case with beveled corners then cut the ground wire to 1" and wrapped it around the cable clamp screw then did the same with the second NM cable but entered top of box. Over the years I replaced most of the old NM with 12/2 NMB.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Side note: Years ago you were allowed to run a ground wire to a metal box but thought that I read a few years ago that is no longer allowed. Believe article or person stated that if you are able to install a ground wire would be safer to pull in a new NMB cable to replace the NM cable without a ground wire
Its still allowed, unless you have a local amendment banning it, see 250.130 (C).
I often find it easier than re-wiring or replacing a old metal box in lathe and plaster.
I have ran into situations where the old box has C shaped channel that the lathe sits in so there is no way to remove it without disturbing the whole wall.
I run a solid green back to the nearest point on the GEC.
What is illegal is running to something else like a metal water pipe.
 

kwired

Electron manager
Location
NE Nebraska
Its still allowed, unless you have a local amendment banning it, see 250.130 (C).
I often find it easier than re-wiring or replacing a old metal box in lathe and plaster.
I have ran into situations where the old box has C shaped channel that the lathe sits in so there is no way to remove it without disturbing the whole wall.
I run a solid green back to the nearest point on the GEC.
What is illegal is running to something else like a metal water pipe.
That once was allowed as well. I even remember doing so a time or two early on in my career. I think that went away about same time they started requiring the GEC to run to first five feet of entry on water pipe electrodes, so maybe about 1996 NEC? Though I think you still can run such an EGC to that portion of piping that qualifies as an electrode
 

letgomywago

Senior Member
Location
Washington state and Oregon coast
Occupation
residential electrician
Its still allowed, unless you have a local amendment banning it, see 250.130 (C).
I often find it easier than re-wiring or replacing a old metal box in lathe and plaster.
I have ran into situations where the old box has C shaped channel that the lathe sits in so there is no way to remove it without disturbing the whole wall.
I run a solid green back to the nearest point on the GEC.
What is illegal is running to something else like a metal water pipe.
I've done this before to utilize existing home runs in kitchen remodels. I pull the 1 or 2 circuits needed and add grounds from those to the new jumpers and it back tracks all the way to the old home runs with their GFIs.
 
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