Line -> Ground not 120...

[sw_ross]

On a service call yesterday for a "non-working" receptacle:

Structure is an old building that is described by owner as a "Hostile" (nightly accommodations).
She was told of a receptacle (fridge) that wasn't working so I was called out.
Original wiring of structure is conduit and metal boxes, additional wiring various renos is NMB and plastic boxes.

When I looked at Recep it showed power with my NCV tester. I pulled the Recep out and checked voltage. It had 120v L->N, but only 30v L->G (metal box & conduit- no ground wire).
Thinking that was a little odd I opened up another nearby Recep (NMB & plastic box, different ckt) it had 120 L->N, and 50v L->G.

I ohm'd out N->G with no continuity.

The panel is a mess. I wasn't able to find a bonding jumper (yet).
When I checked continuity between the neutral bar and the conduits coming into panel my tester (fluke t5) rang out for continuity but also rang out for voltage (additional warning sound).

I plan to go back after the weekend and do some further checking with my other fluke meter.

...Ever have one of those service calls that just eats at you at 2am when you're trying to sleep but you can't stop trying to process the issue?... Ruins a perfectly good Saturday night sleep and sleeping in on Sunday morning!

 

[ptonsparky]

On a service call yesterday for a "non-working" receptacle:

Structure is an old building that is described by owner as a "Hostile" (nightly accommodations).
She was told of a receptacle (fridge) that wasn't working so I was called out.
Original wiring of structure is conduit and metal boxes, additional wiring various renos is NMB and plastic boxes.

When I looked at Recep it showed power with my NCV tester. I pulled the Recep out and checked voltage. It had 120v L->N, but only 30v L->G (metal box & conduit- no ground wire).
Thinking that was a little odd I opened up another nearby Recep (NMB & plastic box, different ckt) it had 120 L->N, and 50v L->G.

I ohm'd out N->G with no continuity.

The panel is a mess. I wasn't able to find a bonding jumper (yet).
When I checked continuity between the neutral bar and the conduits coming into panel my tester (fluke t5) rang out for continuity but also rang out for voltage (additional warning sound).

I plan to go back after the weekend and do some further checking with my other fluke meter.

...Ever have one of those service calls that just eats at you at 2am when you're trying to sleep but you can't stop trying to process the issue?... Ruins a perfectly good Saturday night sleep and sleeping in on Sunday morning!

Why didn’t you post at 2 AM? Slacker. You could have been back to the job by now.

Are you sure the fridge isn’t toes up? Run a cord to a known good receptacle (install a temp if need be) and test it. Did you check L1-L2, L1-N, L2-N?

Sounds like you’re missing a Neutral bond at the Service entrance but the fridge may still be TU.

 

[sameguy]

Homerun in pipe? That's your ground. Sounds like frig is doa.

 

[augie47]

not that you should, worry. Now that you have touched it, IF the fridge is DOA it will be YOUR fault

 

[jaggedben]

The readings might make sense for half-decently earthed equipment grounds but no main bonding jumper on premises. Metal water piping network in neighborhood? Possibly something is faulted to ground and flowing back on the water pipes to someone else's service neutral, but that's a high impedance path. Result is a large voltage drop on the ground, and equipment grounds are hot to neutral because the neutral is ready to trip that breaker once the main bonding jumper is installed. If there's no main bonding jumper, turn off everything before installing one, so that the MBJ doesn't arc as you're putting it in. Then turn everything back on one by one and see if something trips.

I agree with other posters that there's no evidence this is related to the fridge dying, and you need to determine if it still works at all. Charge extra for solving two problems.

 

[electrofelon]

You should test with a low impedance meter as it will be more meaningful. That would tell you if the "ground" has a no connection back to the source, or a "poor" connection back to the source.