replacing 2 wire outlets

[growler]

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.

The first thing to do when you see this installation is to make sure the system is grounded in the first place. Having three wires at a junction box doesn't mean the service is grounded. If you have a good ground at the service and the wiring is still in good shape there is nothing wrong with useing the old #16 ground wire. It was legal at the time of installation.

Be suspicious when you see two pronged receptacles of the service not being grounded. Even if it was grounded it may not be now.

 

[480sparky]

The service ground and the branch circuit ground are two different animals.

You can have a service with a ground rod and a GEC to the water pipe, but not ground wire in the branch circuit.

You can also have grounded NM in the branch, but no grounding at the service.

 

[al hildenbrand]

Consensus??....More like assumption.

No, I meant "consensus" (def.: agreement in opinion). This is an AHJ consensus for the State.

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

I totally agree with your caution.

In a normal residential setting, because one cannot see the rest of "any old cable" when one is contemplating replacing a two wire receptacle with a grounding receptacle, one should, at least, check the continuity and resistance of the "apparent" EGC. For this thread, my comments are about reduced gage EGC NM. . .my comments about FMC and BX are meant to illustrate other "old Code" wiring methods my AHJ says can be used as EGCs while in their "as originally installed" condition.

Even with continuity and low resistance, as I describe in my post above, and as 220/221's post illustrates, the quality of the reduced gage EGC NM splices in the late 50s and thru the 60s is worthy of being cautious about. If one is familiar with the local installation techniques from that time period, one is in a better position to more quickly assess the particular branch circuit one is looking at.

Putting the grounding receptacle in, using the reduced gage EGC, is, in my area, a normal practice, for a simple receptacle outlet maintainance.

 

[LarryFine]

Larry gives his blessing.

Well, that's all that matters, right? :grin:

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.

One could certainly argue that the same caveat applies to existing installations with full-sized EGC's.[/quote]

 

[al hildenbrand]

One could certainly argue that the same caveat applies to existing installations with full-sized EGC's.

Absolutely.

 

[LarryFine]

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.

Same here, about the beginnings of EGC-equipped NM. In fact, on many older jobs, I've seen the home run go to, for example, the bathroom light, switch, and receptacle (if there was one), and then the circuit would continue with NM without an EGC for the rest of the circuit. Same with kitchen receptacles and near-sink switches.

 

[LarryFine]

You can have a service with a ground rod and a GEC to the water pipe, but not ground wire in the branch circuit.

You can also have grounded NM in the branch, but no grounding at the service.

The first thing to do when you see this installation is to make sure the system is grounded in the first place.

The system need not be 'grounded' as long as the EGC is connected to the supply neutral.

 

[LarryFine]

In a normal residential setting, because one cannot see the rest of "any old cable" when one is contemplating replacing a two wire receptacle with a grounding receptacle, one should, at least, check the continuity and resistance of the "apparent" EGC.

Absolutely, and with a solenoid or other type tester with a lower impedance than a typical voltmeter. And this applies to even a full-sized existing EGC. I would never suggest relying on an untested EGC method, regardless of size, type, or age.

 

[LarryFine]

One could certainly argue that the same caveat applies to existing installations with full-sized EGC's.

(Edited to remove oops)

 

[Riograndeelectric]

No, I meant "consensus" (def.: agreement in opinion). This is an AHJ consensus for the State.I totally agree with your caution.

In a normal residential setting, because one cannot see the rest of "any old cable" when one is contemplating replacing a two wire receptacle with a grounding receptacle, one should, at least, check the continuity and resistance of the "apparent" EGC. For this thread, my comments are about reduced gage EGC NM. . .my comments about FMC and BX are meant to illustrate other "old Code" wiring methods my AHJ says can be used as EGCs while in their "as originally installed" condition.

Even with continuity and low resistance, as I describe in my post above, and as 220/221's post illustrates, the quality of the reduced gage EGC NM splices in the late 50s and thru the 60s is worthy of being cautious about. If one is familiar with the local installation techniques from that time period, one is in a better position to more quickly assess the particular branch circuit one is looking at.

Putting the grounding receptacle in, using the reduced gage EGC, is, in my area, a normal practice, for a simple receptacle outlet maintainance.

Thank you all for your input. this is why I ove this site so much great help here. you brought up some very good points.

I never assume that since there is a grounding condcutor that the branch circuit is grounded.

I will always install either a gfci if there is room in the box or a 2 wire replacement . this is espceially true forwhen I run across old 2 wire BX cable

 

[zappy]

do you mean like a wiggy?hot to grd.

do you mean like a wiggy?hot to grd.

Absolutely, and with a solenoid or other type tester with a lower impedance than a typical voltmeter. And this applies to even a full-sized existing EGC. I would never suggest relying on an untested EGC method, regardless of size, type, or age.

to see if it reads 120V.

 

[220/221]

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

It was a transition period when grounded romex came into play but 3 wire receps were not yet required. I see it all the time and I use the ground.

It's a gray area. An inspector could find a code reference somewhere to turn it down.

 

[LarryFine]

do you mean like a wiggy?hot to grd. to see if it reads 120V.

That's exactly right. A 100w bulb might even be a better test.

 

[Mule]

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.

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

Is this ground a "snagged" ground? if so that was never legal was it? The way I understand it, is that "Snagged" or "Added" grounds would have to go all the way back to the bullseye bonding point or the electrode.