replacing 2 wire outlets

Status
Not open for further replies.

Riograndeelectric

Senior Member
Ok so on an old romex system wired with 2 conductors and #16 bare ground wire from the late 1950s and having 2 wire outlets can you legally repalce them with 3 wire grounded outlets even though the grounding conductor is not full size.
I know you can install a GFCI outlet and protect all down stream outlets with 3 wire devices.
I do not think you can use a GFCI breaker instead of a GFCI outlet or can you and use 3 wire devices.
 

iaov

Senior Member
Location
Rhinelander WI
Riograndeelectric said:
Ok so on an old romex system wired with 2 conductors and #16 bare ground wire from the late 1950s and having 2 wire outlets can you legally repalce them with 3 wire grounded outlets even though the grounding conductor is not full size.
I know you can install a GFCI outlet and protect all down stream outlets with 3 wire devices.
I do not think you can use a GFCI breaker instead of a GFCI outlet or can you and use 3 wire devices.
If this installlation had a 16 grnd wire why did they use two prong outlets?? I believe you can ground fault protect them with either method but when you install the three wire devices hook up those ground wires!
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I am not sure. IMO the 16 gauge ground is better than nothing but I don't know how the NEC looks at that. You certainly can use a GFCI breaker and then use 3 wire recep, but would you connect the ground? I would..... I think
 

480sparky

Senior Member
Location
Iowegia
iaov said:
If this installlation had a 16 grnd wire why did they use two prong outlets?? I believe you can ground fault protect them with either method but when you install the three wire devices hook up those ground wires!

If it was the late 50s, maybe they had 2-slot receps on the truck since most homes then were ungrounded anyway. NM with a bonding wire was sumpin' new.
 

Buck Parrish

Senior Member
Location
NC & IN
I think the op wants to know if it is code compliant to use a 16 gauge grounding wire on a 15 amp circuit. With three prong oulets and With out gfci protection
I don't think it is.
 

480sparky

Senior Member
Location
Iowegia
buckofdurham said:
I think the op wants to know if it is code compliant to use a 16 gauge grounding wire on a 15 amp circuit. With three prong oulets and With out gfci protection
I don't think it is.

If so, we had a discussion about this just recently. But I can't find the thread on it.
 

Riograndeelectric

Senior Member
buckofdurham said:
I think the op wants to know if it is code compliant to use a 16 gauge grounding wire on a 15 amp circuit. With three prong oulets and With out gfci protection
I don't think it is.

this is what I am asking .

can I get by with out using GFCI prtection using a #16 bare ground wire on a 15 and 20 amp circuit
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Riograndeelectric said:
this is what I am asking .

can I get by with out using GFCI prtection using a #16 bare ground wire on a 15 and 20 amp circuit

I don't believe you will find a definitive answer in the NEC on this. I also cannot find another that say you cannot use the existing undersized ground with a 3 wire recep.
 

Buck Parrish

Senior Member
Location
NC & IN
Riograndeelectric said:
this is what I am asking .

can I get by with out using GFCI prtection using a #16 bare ground wire on a 15 and 20 amp circuit

I think the grounding conductor has to be the same size as the current carrying circuit .
That old 16 solid breaks very easy.
 

resistance

Senior Member
Location
WA
Dennis Alwon said:
I don't believe you will find a definitive answer in the NEC on this. I also cannot find another that say you cannot use the existing undersized ground with a 3 wire recep.

This I agree with. We have always used the existing EGC's on full face (new word) receptacle devices.

Yet, I'm sure someone will try to throw 250.122(A) in the loop.
 

tallguy

Senior Member
resistance said:
This I agree with. We have always used the existing EGC's on full face (new word) receptacle devices.

Yet, I'm sure someone will try to throw 250.122(A) in the loop.
Wouldn't the answer be in 406.3(D)(1)?

Sounds like one of those muddy "grandfather" issues... it's going to be up to the AHJ to opine as to whether or not that #16 is sufficient to say that "a grounding means exists in the receptacle enclosure". Strikes me that this is pretty deliberately vague -- else reference would be made to 250.122(A) there.

Presumably complying with 250.130(C) is not in view for the OP.

If he gets a thumbs up from the AHJ on 406.3(D)(1), fine. Otherwise, 406.3(D)(3)(b) or (c) is what he is stuck with. right?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I'd say you absolutely can use grounding receptacles on the existing under-sized-EGC NM cable. It was compliant when installed, and if any original receptacles were grounding, they were installed using that same undersized EGC.

You're simply replacing devices, not making a new installation. If you were installing a new circuit or circuit extension, that would be a different story. You'd need to use GFCI protection or run a new EGC-equipped cable.

Note: any time you use a GFCi device to protect a 2-wire circuit, you must not make any connection to any EGC anywhere, such as between receptacles. You could otherwise energize one appliance from a fault inside another.
 

Riograndeelectric

Senior Member
Presumably complying with 250.130(C) is not in view for the OP.

I can comply with 250.130(C) I am trying to determine if the orginal grounding condcutor would be sufficent.

what about 250.122 Tables
 

tallguy

Senior Member
Riograndeelectric said:
Presumably complying with 250.130(C) is not in view for the OP.

I can comply with 250.130(C) I am trying to determine if the orginal grounding condcutor would be sufficent.

what about 250.122 Tables
250.122 definitely isn't going to help, other than telling you what you'd need to do to be up to current code.

Larry gives his blessing. I say best to inquire of your local friendly AHJ re: 406.3(D)(1) than to get in a fracas about it later.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Riograndeelectric said:
what about 250.122 Tables
That's still using contemporary Code on an existing installation assembled under an earlier Code.
LarryFine said:
I'd say you absolutely can use grounding receptacles on the existing under-sized-EGC NM cable. It was compliant when installed, and if any original receptacles were grounding, they were installed using that same undersized EGC.
I agree with Larry, but with a caution.

When the requirement for NM to have an EGC manufactured in it went into effect, the installation techniques varied from electrician to electrician. The real question is whether the 16 gage EGCs, in the installation that is the subject of the Opening Post, are adequately spliced along the path back to the Service.

The first summer of my apprenticeship was the last summer that the reduced gage EGCs were manufactured. I was actually taught to do nothing more than twist the EGCs together for about five wraps and then to run one under the device grounding terminal. There was no bond to the metal boxes. There was no pressure connector, solder or anything else, used on the twisted EGCs. When we occasionally worked on weekends, outside of the local jurisdiction, the AHJ joined our crew (for a second job), and he instructed us on this exact technique.

Where I work now, the consensus is that existing Flexible Metal Conduit, of any length, as originally installed, IS an effective EGC. On such a circuit, a 2 wire receptacle can be replaced by a grounding receptacle, with appropriate bonding at the wall case. However, if I add or change conductors in the FMC, I must pull in an EGC.

Also, old AC, with or without the drain wire, is an "effective" EGC. On such a circuit, a 2 wire receptacle can be replaced by a grounding receptacle, with appropriate bonding at the wall case.

IMO, the real question is whether the resistance of the EGC is low enough to be "effective" as an EGC under the original Code in effect at the time of assembly.
 

220/221

Senior Member
Location
AZ
If this installlation had a 16 grnd wire why did they use two prong outlets??

Around here they started using ground wires several years before they started using grounded outlets. I see it all the time. They would just ground the box on the clamp screw. Sometimes they would poke it out of the box and ground it on the outside.

Like GFCI's, they started first putting them in bathrooms, then kitchens, then all circuits. Before they had the grounded cable, they would run a separate bare ground.

DSC01512.jpg


As far as code??? Sounds like a murky gray area. Personally, I never hesitate to use the ground, even though it is undersized.
 

hillbilly

Senior Member
al hildenbrand said:
Where I work now, the consensus is that existing Flexible Metal Conduit, of any length, as originally installed, IS an effective EGC. On such a circuit, a 2 wire receptacle can be replaced by a grounding receptacle, with appropriate bonding at the wall case.

Also, old AC, with or without the drain wire, is an "effective" EGC. On such a circuit, a 2 wire receptacle can be replaced by a grounding receptacle, with appropriate bonding at the wall case.

IMO, the real question is whether the resistance of the EGC is low enough to be "effective" as an EGC under the original Code in effect at the time of assembly.

Consensus??....More like assumption.

That last sentence says a lot.
If the resistance of that old AC armor is too great to open the fuse or breaker protecting the circuit, you can have a red hot piece of metal in the wall in the event of a ground fault.

No way would I assume the armor on any old cable is sufficient for use as a EGC.

Just a opinion
steve
 
Status
Not open for further replies.
Top