Trouble shooting question for the old timers

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nickelec

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I'm pretty stumped here the run down currently in the process of redoing a service for a customer the old panels are completely rotted with old cloth wiring through out I have one ckt thats giving me an issue and I didn't even touch the old stuff yet! What a coincidence we all been there. The issue is I have a few lights out on one ckt when I test from hot to ground I get 120 ground to nutreal 120 and hot to nutreal 120 but no lights ? I'm thinking bad nutreal somewhere ?

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And also I was thinking maybe it's possible that since there's no ground due to all the corroded cable panels boxes Etc. There could possibly be a short somewhere but it's not tripping on blowing a fuse cause there's no path back to the ground

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nickelec said:
I'm pretty stumped here the run down currently in the process of redoing a service for a customer the old panels are completely rotted with old cloth wiring through out I have one ckt thats giving me an issue and I didn't even touch the old stuff yet! What a coincidence we all been there. The issue is I have a few lights out on one ckt when I test from hot to ground I get 120 ground to nutreal 120 and hot to nutreal 120 but no lights ? I'm thinking bad nutreal somewhere ?

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You should not be getting 120V from neutral to ground. You might have a small amount of voltage due to voltage drop in the neutral but no where near 120V.

Without being there or more info, anything I would say would just be a guess. I would take the circuit apart in the middle and see if you have 120V. Maybe make a test light out of a pigtail socket to confirm the voltage. Work your way either away from the middle towards the end or back towards the panel, depending on what you find midway.
 
use a light bulb instead of your digital meter.
 
Draw the circuit. We need to know where in the circuit you are taking measurements.

Old cloth covered rarely has an EG so how are you referencing ground?

An open neutral would give you 120v to EG, or earth, but it would show 0v to line at that same point, or 240 if you hit the other leg.
 
I forgot to mention this is BX ac cable and right now there's only one phase to the house

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So your ground isn't a ground in the 12/2 with ground BX?

Does it leave the panel in the correct configuration. If so find the first box and go from there, you can take them all apart or start with and 3-way looking ones.
 
neutral is the switched conductor in the light circuit and the switch is open at the time you are taking measurements?

Was pretty common to switch the neutral in K &T wiring and cloth covered cables are about as old and maybe some carryover of that practice when it was installed.
 
The neutral isn't switched the way that the older homes are commonly wired here is the feed is brought up from the panel to the first receptacle from there it goes to all the celling points that are on that ckt. Then from the celling point there is 12/2 that goes to a switch so there are no neutrals in the switch location.

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I was saying yesterday that I needed a pigtail and bulb. Had none on the truck!! I don't think if I go across the hot and neutral the bulb with light .. Unless we wouldnt be having this discussion. It was 1030 pm when this happened I gave the customer a lamp and told her it can not be fixed until service is completely done.

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nickelec said:
The neutral isn't switched the way that the older homes are commonly wired here is the feed is brought up from the panel to the first receptacle from there it goes to all the celling points that are on that ckt. Then from the celling point there is 12/2 that goes to a switch so there are no neutrals in the switch location.

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So you have both 120 volt conductors at the light outlet box and a switch loop, switch loop can switch either of the 120 volt conductors and the light will still turn on and off, but if you switch the neutral every point on lampholder with an installed working lamp will be 120 volts to ground when the switch is open.
 
kwired said:
neutral is the switched conductor in the light circuit and the switch is open at the time you are taking measurements?

Was pretty common to switch the neutral in K &T wiring and cloth covered cables are about as old and maybe some carryover of that practice when it was installed.
Click to expand...
But as you said in OP "bad neutral somewhere" is your guess. Open neutral is my guess as well, was just suggesting that intentionally switching the neutral creates the same situation and that you should consider that as a potential issue that is present. A failed switch that won't close can easily mislead you if it is switching the neutral conductor instead of an ungrounded conductor. If you measure voltage across the switch when it is in the "on" position then the switch is failing to close regardless of whether it is switching the grounded or ungrounded conductor.
 
kwired said:
So you have both 120 volt conductors at the light outlet box and a switch loop, switch loop can switch either of the 120 volt conductors and the light will still turn on and off, but if you switch the neutral every point on lampholder with an installed working lamp will be 120 volts to ground when the switch is open.
Click to expand...

He didn't say that the neutral went from the receptacle to the switch, but is that how you see it? From his description the switch is at the far end of the hot leg.
 
The switches are on the neutral side of the fixture. Turn the light off, and the neutral is no longer a grounded conductor.... it is an ungrounded conductor. Hence, 120v to ground.
 
gadfly56 said:
He didn't say that the neutral went from the receptacle to the switch, but is that how you see it? From his description the switch is at the far end of the hot leg.
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he said home run went to a receptace, then a run was made to the ceiling, from there a switch loop to the switch location, he did not say which circuit conductor was being switched at all. If the neutral conductor is the one that is switched the conditions he is encountering is exactly what you will see when the switch is open. It is also what you will see if the neutral is open any place else, I just wanted to remind him that the switched neutral would give the impression something is wrong, which code wise it is, but operational wise it would still work.
 
Hey all so I finally finished the service. And the problem presist. The nutreal wasn't switched I determined there was a broken nutreal conductor some where and just re fed the location that was failing. It will remain a mystery. But I will point out that when I was using the pig tail tester when I went from ground to nutreal the bulb would light up dim and also turn on a lamp that was plugged into an outlet on the same ckt.

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