Can ac electric “leak” to ground?

[vavet]

Rental house we’ve owned since 2006 and lived there until 2015. While we lived there, I hired an electrician to come out and install an outlet in the living room floor so we could have an end table with lamp there.

Our current tenants, moved in there last month, noticed the outlet didn’t work. Previous tenant did not mention it, but maybe they didn’t use it.

I pulled the outlet cover off and measured 20v ac with my meter across the black and white wires.

I go down in the crawl space, I know this is on the same circuit as the crawl space lights. Those are working, as is a receptacle in the crawl space. I go to find the outlet box. It’s just one piece of 14/2 times going in, then I find a junction box a few feet away that is feeding that single piece of romex. It has romex running back towards the crawl space light switch where it gets power. It also has a piece of romex running perpendicular towards the front of the house. The third piece is feeding the floor outlet.

I remove the blank cover plate off the jb. Nothing is wire nutted. One of the black wires kinda falls loose from the other two black wires that are half- heartedly twisted together. The two that are together are the source line and the mystery destination that appears to run through the front foundation wall. The black wire that fell loose is the one for the floor outlet.
I can’t imagine what the power going through the foundation wall is for. But does this somehow explain the 20v ac on the floor outer?

Ultimately, I disconnected the mystery wire, reconnected and wire nutted the floor outlet to line voltage, and reattached the face plate. The floor outlet now has 120v, although… plot twist… I can only insert my outlet tester into one of the receptacles. It’s not one of the child proof outlets. Perhaps something fell down in there and is jamming it? That’s another mystery for another day.

So It seems like whatever was happening with the mystery wire running through the foundation wall was causing the drop to 20v. If that wire is running underground and got partially or completely cut, would it “leak” to ground? Wouldn’t the circuit breaker trip?
For the record, there is a planting bed just on the other side of that foundation wall and there is a black round cable in that area- I always figured that was an abandoned cable tv line, but I don’t really know. I did some digging in that area a couple months ago to put in some new bushes. Maybe I hit it then?
The circuit looks something like the attached drawing.

 

[manwithtools]

What you had was just a poorly made wire junction in the wire nut.

 

[65ranchero]

Could the line going out of the wall might have powered a post lamp that is no longer there?

 

[wyliesdiesels]

A "leak to ground" wouldnt cause the voltage to drop. that defies electrical theory.

what you had was a poor connection, that when resistance is put on it, causes the voltage to drop because the connection is poor.

 

[rattle_snake]

Yes, the current all goes to earth ground. That is the other half of the circuit from the power plant.

Actually the electrons come out of ground not in.

A GCFI is a ground leak detector.

 

[wyliesdiesels]

Yes, the current all goes to earth ground. That is the other half of the circuit from the power plant.

100% wrong for a split phase or 3 phase service to a building. the current returns to the source (transformer). The earth is a very poor conductor of electricity especially at low voltages. the current returns to the transformer via the service drop or lateral.

and comparing electrical service on a building to a SWER (single wire earth return) primary power distribution is a flawed comparison.

Actually the electrons come out of ground not in.

wrong again. where do you come up with this ****? The EGC on a circuit isnt even used during normal operation so how could the electrons come out of the ground?

A GCFI is a ground leak detector.

yup and a GFCI doesnt even measure current on the ground. there goes your bogus theory about electrons coming out of the ground

 

[vavet]

What you had was just a poorly made wire junction in the wire nut.

so a poor connection would drop the voltage from 120 to 20?
I didn’t know that.

Could the line going out of the wall might have powered a post lamp that is no longer there?

it certainly could. There’s no other evidence of that and no other houses have that, at least not that I’ve noticed. I think most houses in the neighborhood were built around the same time by the same builder. I will take a drive around next time I’m over paying attention to the presence or absence of post lamps.

A "leak to ground" wouldnt cause the voltage to drop. that defies electrical theory.

what you had was a poor connection, that when resistance is put on it, causes the voltage to drop because the connection is poor.

I didn’t think it did, but I also didn’t think a poor connection would drop the voltage like that either. Both you and manwithtools are thinking the same thing, so…what is it, Ockhams razor that says the most likely cause is the one that requires the least assumptions.

 

[manwithtools]

so a poor connection would drop the voltage from 120 to 20?
I didn’t know that.

Ywp, it can be any kind of weird voltage when a poor connection is in the circuit. It can even be induced voltage from another current carrying conductor in a cable.

 

[dave*99]

so a poor connection would drop the voltage from 120 to 20?
I didn’t know that.

What type of meter did you use? If it is a digital multimeter with the typical 1 or 10 megohm input resistance, it's quite possible you are measuring capacitively coupled (phantom) voltage. The broken connection at the wire nut you mention can provide such a voltage.
An analog meter or a DMM with a Lo-Z (low impedance) setting for AC volts would read zero is this is the case.

Try sticking the red meter probe into the receptacle (the side connected to the black wire) and leave the black lead on the floor.
This receptacle is properly connected to 120 VAC, but the open lead makes it read 17.07 VAC. The bad connection you found can yield similar results.

 

[dcg9381]

100% wrong for a split phase or 3 phase service to a building. the current returns to the source (transformer). The earth is a very poor conductor of electricity especially at low voltages. the current returns to the transformer via the service drop or lateral.

So, explain it to me like I'm an engineer. The "main" has a bonded N/G connection, so it's always going to "leak" some current to "earth" based on the split between neutral connection (high impedance?) and that N has "low impedance" by residential GFI? AS long as the split doesn't trigger GFI limits, you're good...

Basic ohms law... School me.