Another grounding question

[erickench]

....along with that any metal conduit that may be involved should be changed to PVC...

Actually if there is a metal conduit electrically continuous going back to the service then you should leave it as it is. You would'nt have to use a nonmetallic box. That conduit is the equipment ground. The fault current flows from the box through the conduit and then to the service neutral.

 

[ultramegabob]

Actually if there is a metal conduit electrically continuous going back to the service then you should leave it as it is. You would'nt have to use a nonmetallic box. That conduit is the equipment ground. The fault current flows from the box through the conduit and then to the service neutral.

odds are if they ran UF the cable is direct buried and any conduit would only be in place for physical protection of the cable where it exits the ground and is exposed on the structure.

 

[erickench]

Now I would like to ask a question. This GFCI receptacle that is bonded to the box, does anyone know if the grounding terminal is electrically tied to the neutral inside the device?

 

[ultramegabob]

this is what the original poster said...

All wires are terminated on there correct terminal screw: hot to gold, nuetral to silver and ground to green.

they make no mention of an intentional connection from neutral to ground.


***if you are talking about the actual GFCI having an internal connection from ground to neutral, it should not unless somthing is defective with it...

 

[erickench]

We would have to assume that the green wire is tying the GFCI receptacle to the box. My question is what is the internal wiring of the device? Where is the current coming from that is energizing the box with this small potential?

 

[ultramegabob]

thats where you need to go back and read my troubleshootin suggestions, it could be bad insulation between conductors in the cable itself, or the ground and neutral coud be wirenuted together in the house where they tied into the circuit.

 

[erickench]

But how is the current flowing from the receptacle to the box? Ground tied to neutral inside the house would not cause this because there is no ground wire inside the cable in question. Nor would the two conductors shorted out inside the cable bring this about because the OCPD would interrupt the circuit. There are two ways that current would flow from the GFCI receptacle to the box. Either through the metal yoke fastened to the box or the ground jumper connecting the box and the receptacle together. It just may be that the neutral inside the device is touching the frame or the grounding terminal.

 

[ultramegabob]

the way I picture what the original poster is working with is 12-2 with ground UF tied into a building that doesnt have ground wires in it.

 

[erickench]

That's right there is no ground connection between the house and the GFCI receptacle. The current can only be coming from GFCI recptacle itself.

 

[Dennis Alwon]

That's right there is no ground connection between the house and the GFCI receptacle. The current can only becoming from GFCI recptacle itself.

It is possible that the ungrounded conductor is nicked and is touching the box.

 

[ultramegabob]

I think this may be my final reply to this subject because I am getting a headache.... the groundwire in the cable could also "not" be connected inside the building and have a power to ground fault inside of the cable which would engergize the metal box and would be felt by touching it..... like I said before, you need to go back and read my troubleshooting suggestions....

 

[erickench]

Then the shock would be greater than a small tingling sensation. The neutral would'nt be as great.

 

[don_resqcapt19]

Don, what does 12/2 UF mean?

UF is like NM but intended for use underground. Just like 12-2 NM, it will have an EGC unless it was made a long time ago. I think a full size EGC was required in these cables starting in the mid 60's and prior to that they had a reduced sized EGC.

 

[ultramegabob]

I am getting the feeling that you are a forum troll....

 

[erickench]

I think this may be my final reply to this subject because I am getting a headache.... the groundwire in the cable could also "not" be connected inside the building and have a power to ground fault inside of the cable which would engergize the metal box and would be felt by touching it..... like I said before, you need to go back and read my troubleshooting suggestions....

But there is no ground wire. You yourself confirmed that there are only two conductors inside the cable. One would have to be the hot lead and the other would be the neutral. No ground conductor.

 

[ultramegabob]

I havent decided yet for sure, either you cannot read, or you are a troll, still debating....

 

[erickench]

UF is like NM but intended for use underground. Just like 12-2 NM, it will have an EGC unless it was made a long time ago. I think a full size EGC was required in these cables starting in the mid 60's and prior to that they had a reduced sized EGC.

Don if the cable has two #12 conductors then where is the third wire for the ground?

 

[don_resqcapt19]

Don if the cable has two #12 conductors then where is the third wire for the ground?

They don't call out the grounding conductor on NM or UF cable. A 12-2 cable will have 3 #12 conductors, assuming it was made after the mid 60s, one white, one black and one bare.

 

[erickench]

Okay, you settled it.

 

[tryinghard]

That's right there is no ground connection between the house and the GFCI receptacle. The current can only be coming from GFCI recptacle itself.

Not true at all especially with multi-outlet branch circuits! In fact most often the neutral is broken towards the supply and routes through many outlets. If this is the case you need to think about where the neutral current will be traveling from 110v usage ahead of this outlet in question, especially if someone has done what your suggesting upstream (which is very common in old homes).

Neutral current will travel all paths according to each level of resistance. Hence what I mean when I say to qualify the circuit neutral. Drape a new one from panel to outlet if needed to prove, but fix the problem. Premises wiring systems have never been exempt of equipment grounding including effective ground fault paths, not 40's/50's/60's or ever regardless if the non metallic including the equipment ground conductor or not. 12-2 means two insulated conductors and one equipment ground, 12-3 includes three insulated conductors and one equipment ground?

Bonding past the service disconnect is not allowed as the rule with few exceptions, this is to eliminate parallel neutral current where it does not belong. I bet the reason there is potential right now is because someone did what you?re suggesting in violation and erroneously but I bet there is illegal (hazardous) bonding involved.