Reduced size ground on older Romex

Status
Not open for further replies.
B

bjp_ne_elec

Senior Member
Location
Southern NH
A little unsure on this, but I have a situation where an existing bathroom has both a 15A and a 20A circuit feeding it - but what's the NEC say about continuing a circuit within the bathroom. Both pieces of ROmex have that reduced ground that they ran probably back in the 60's. Did find a nice splice in the ceiling, with not box, when the GC pulled the ceiling down.

To get a new HR from the panel would be a nightmare.

I know you can replace a ungrounded receptacle with a GFI, but what about the reduced ground, in this bathroom situation? Can you insert a GFI, even though the ground is undersized? Like to see a code reference, in what covers this situation.

Thanks
 
The EGC has nothing to do with the operation of a GFCI device. It contains a differential transformer which monitors the current flow between the ungrounded and grounded conductors detecting leakage.
 
Can I add to an existing circuit with the reduced sized ground?

Dcspector - from your response, I think you're implying that if one were just installing a GFI in an existing box - with the reduced ground - then it would be no issue. But in my situation, the circuit has to be extended.

Thanks
 
I would have to say no on extending from the small EGC per 250.122 but I have been known to be wrong. Also, I wonder if there is an EGC for the GFCI would it have to meet 250.122 as well even if one would not need it per 406.3(D)(3) when an EGC does not exist.
 
Last edited:
My guess is it's probably 16- or 18-guage.

Back in those days, T250.95 stated #16 ground wire for a 20-amp circuit. Full-size grounds we're required until 1968.
 
Last edited:
In my opinion the NEC is silent on this particular issue. It deals with 'no grounding means whatsoever' and of course it deals with modern grounding means.

It does not deal with 'it used to be OK and now it's not' so well.

Old BX and old NM with down sized grounds both have the same issues when extending from them.

Do you treat it like no ground present, or like there is a ground present?

I think the only 'correct' answer will come from the person inspecting the work.

I might extend from either old circuit but also install a GFCI breaker.
 
In Mass we have rule three it could be used as a good rule of thumb;

Rule 3. Additions or modifications to an existing installation shall be made in accordance with this Code without bringing the remaining part of the installation into compliance with the requirements of this Code. The installation shall not create a violation of this Code, nor shall it increase the magnitude of an existing violation.
Click to expand...


So does adding to this circuit increase the magnitude of the violation??
 
M. D. said:
In Mass we have rule three it could be used as a good rule of thumb;



So does adding to this circuit increase the magnitude of the violation??
Click to expand...



Without being on the job, I cannot say for sure, but from the description, I do not see an existing violation.
As Bob mentioned, the NEC is somewhat quiet on this issue - maybe time for a proposal.

I see two ways to look at this. If you are very concerned, install a new homerun.
Otherwise extend the circuit, using whatever is compliant today.
 
I kind of just ask myself " do I want to add more equipment requiring grounding ,..to a circuit with an undersized grounding conductor?"

Most of the time the answer is no. does adding such equipment increase the magnitude ?? I'm not sure but I think we went to a full size grounding conductor because the undersized ones burned off and were physically lacking strength.
 
I run across it all the time.


I employ the don't ask, don't tell policy.

In my mind it's a ground, it's fine.
 
M. D. said:
In Mass we have rule three it could be used as a good rule of thumb;

So does adding to this circuit increase the magnitude of the violation??
Click to expand...

I would say yes. You are adding to a circuit and, in efferct, undersizing the ground.
 
220/221 said:
I run across it all the time.


I employ the don't ask, don't tell policy.

In my mind it's a ground, it's fine.
Click to expand...

None of that will surprise the regular readers of your posts. :grin:
 
Status
Not open for further replies.
Top