This ever happened to you, Trouble shooting call, problem elusive?

[dmagyar]

I received a call Friday from a new client. They had a power outage in a sizable portion in their house and needed some help. I went over and started to look over the problem. In the first switch box I opened up the upstream neutral had voltage to ground, along with the ungrounded conductor. I've done some other calls where the circuit has lost the power, but this with the neutral becoming energized was a new twist. (without it being the fault of bad three way conneciton using the white wire). I began to open boxes and isolate the upstream feed and neutrals, but the circuit was not installed by any logic that I could discern. I pulled out some of my test equipment, my Greenlee 2011 for tracing the circuit, low voltage toner, and my trusty voltage tester but to no avail. Three hours later I called it quits for the night. I came back the next day and continued in the same fashion opening boxes and splices looking for the problem, but no smoking gun. Anyway after about three hours the second day I hadn't found anything that would cause the initial problem, so I start reconnecting the splices in the boxes furthest downstream first. When I had completed the splicing and turn the breaker back on, I see that the problem had disapeared, & the lights are now working as installed. Client was happy, he paid me and I left. But I was still stumped by whatever had caused this in the first place. Any thoughts on what it might have been?

What I did find was: three ways installed correctly by owner, alot of plug strip loads plugged in, a non functioning smoke detector on the same hot, removed no change and alot of switches that had been replaced by the owner, with very small tails which were cut out of the stab in slots, and then re-termed under the side screws. Also were two large groups of neutrals and hots inside one red wire nut respectively (about six wires each, replaced with gray wire nuts). (I did remove the small cut off wires from the slots of the switches).

 

[mcclary's electrical]

I received a call Friday from a new client. They had a power outage in a sizable portion in their house and needed some help. I went over and started to look over the problem. In the first switch box I opened up the upstream neutral had voltage to ground, along with the ungrounded conductor. I've done some other calls where the circuit has lost the power, but this with the neutral becoming energized was a new twist. (without it being the fault of bad three way conneciton using the white wire). I began to open boxes and isolate the upstream feed and neutrals, but the circuit was not installed by any logic that I could discern. I pulled out some of my test equipment, my Greenlee 2011 for tracing the circuit, low voltage toner, and my trusty voltage tester but to no avail. Three hours later I called it quits for the night. I came back the next day and continued in the same fashion opening boxes and splices looking for the problem, but no smoking gun. Anyway after about three hours the second day I hadn't found anything that would cause the initial problem, so I start reconnecting the splices in the boxes furthest downstream first. When I had completed the splicing and turn the breaker back on, I see that the problem had disapeared, & the lights are now working as installed. Client was happy, he paid me and I left. But I was still stumped by whatever had caused this in the first place. Any thoughts on what it might have been?

What I did find was: three ways installed correctly by owner, alot of plug strip loads plugged in, a non functioning smoke detector on the same hot, removed no change and alot of switches that had been replaced by the owner, with very small tails which were cut out of the stab in slots, and then re-termed under the side screws. Also were two large groups of neutrals and hots inside one red wire nut respectively (about six wires each, replaced with gray wire nuts). (I did remove the small cut off wires from the slots of the switches).

It sounds like you found the problem under the big wire nut of neutrals. An open neutral with a lighting load will read energized to line voltage. I believe you made better connections putting it back

 

[dpeter]

My vote is that you corrected an open neutral and did not realize it. It is sure there was an open in the neutral between the first box you opened and the panel.

 

[shepelec]

I've found 90% of this type of problem to be from back stabbed plugs and switches. It can drive you nuts when the circuit starts working and your only half way through checking it out and you don't know why.

 

[Philip Barr]

I had a similar problem with a client last week. I was getting 120v to ground on the neutral, backfeeding through a plugged in load or light fixture upstream of the fault. The problem was a bad backwired receptacle resulting in an open neutral.

 

[cadpoint]

Maybe I missed it, you didn't asked what happened before you got there!

Beside the client involvement; was there a power lose in the neighborhood, someone kiss a power pole?
Anything odd electricial in the house? Someone change hair blower locations?

Oh and why are you working at no charge? :grin:

 

[jumper]

Oh and why are you working at no charge? :grin:

From OP "he paid me and I left", he got paid.:-?

 

[LarryFine]

It can drive you nuts when the circuit starts working and your only half way through checking it out and you don't know why.

That's because you're not monitoring the trouble while you're working.

I always have someone watching the light, or plug in a cord for one if I'm alone, so I see the light flickering when I mess with the right connection.

 

[cadpoint]

Let's review

.... What I did find was: three ways installed correctly by owner, alot of plug strip loads plugged in, a non functioning smoke detector on the same hot, removed no change and alot of switches that had been replaced by the owner,...

No charge, now you could argue that there was no power, But the key is removed ...

 

[George Stolz]

Jude, wipe your glasses. "No change".

 

[e57]

Odds are you may have re-spliced a bad one - and you may never hear of it again... But there have been times where under load a neutral would be resistive - the condition apparent.... Then allowing the load to be removed (You shut the circuit off to re-splice) - the connection cools and it appears the problem is gone. You then think you have done - something.... The reality is all you have done is alter the load - or maybe just breathed enough next to it that the connection is less resistive.

The lost neutral can be elusive that way - specifically if you have not mapped out the circuit completely. Otherwise it would be difficult to tell a good reading in one place may not actually be on the affected portion of the circuit, and you may not know the dividing line of the affected, and non-affected parts.

Since this type of problem can be damaging to the customers appliances and may types of loads they might have on them - I remove them, and unless I find it right away - I put my own 'disposable loads' on the circuit and load it as much as possible. Usually a few 1000w halogen floods, or 500w floods. With the condition still present I open all the boxes and map the circuit and take temp readings of the connections with an IR thermometer - the hot one is it....

Since the high/low voltage condition is dependant on load - while I'm maxing out the circuit to get full current on the neutral to get it to 'fail', I also do the same after I'm done by maxing out both legs of the circuit one at a time before I leave just to make sure I got it.

 

[growler]

Three hours later I called it quits for the night. I came back the next day and continued in the same fashion. Anyway after about three hours the second day I hadn't found anything that would cause the initial problem, Client was happy, he paid me and I left.

Yes it's very unusual to have a happy customer when you spend six hours trouble shooting and still can't give them some sort of explanation of what the problem was.

I'm not saying it can't take time to solve a problem but most customers just assume that all problems can be solved in about an hour.

I agree with the others that it was an open neutral and the problem was probably under the wire nut with all the neutrals not properly spliced ( twisted with proper sized wire nut ). I would have tried to figure out how much of the circuit was still working and that would give an indication of where it was open.

Actually I find there are just about as many problems with the neutral side of a circuit as there are with the hot side. If you think about it then it's about a 50-50 chance of which conductor will open or have a loose connection.

 

[satcom]

Problems like these, are common service calls, and over the years we found that most of them were do to back wired push in devices, splices were a rare cause, something that speeds up the process is to remember that a device that is still working is usually the cause, looking for the dead devices will have you there all day looking.
We had a good one where the power went off every time a truck hit a pot hole in the road, and the power return when another truck hit the pot hole, you just have to love those push in devices!

 

[480sparky]

...........We had a good one where the power went off every time a truck hit a pot hole in the road, and the power return when another truck hit the pot hole, you just have to love those push in devices!

I found one that was caused by the furnace turning on and off.

The back-stabbed device was right above a register. A few minutes after the furnace turned on, the circuit would go off. After the furnace turned off, the power would come back on.

 

[cadpoint]

Jude, wipe your glasses. "No change".

I stroke out on this one, I did read it three times!

Glad to know I'm on a first name basis with some here...

 

[Sierrasparky]

Well I had a similar situation on a service call recently where there was current flow hot to nuetral , Hot to ground , but when you plugged in anything like a lamp you would get nothing. I checked all the recepts and switches on the circuit. But still did not find the problem. The little 7 watt night light worked.
I Scratched my head a bit?????
any guess?

 

[dmagyar]

Wife was happy, Husband happy I was leaving

Wife was happy, Husband happy I was leaving

Yes it's very unusual to have a happy customer when you spend six hours trouble shooting and still can't give them some sort of explanation of what the problem was.

I'm not saying it can't take time to solve a problem but most customers just assume that all problems can be solved in about an hour.

I agree with the others that it was an open neutral and the problem was probably under the wire nut with all the neutrals not properly spliced ( twisted with proper sized wire nut ). I would have tried to figure out how much of the circuit was still working and that would give an indication of where it was open.

Actually I find there are just about as many problems with the neutral side of a circuit as there are with the hot side. If you think about it then it's about a 50-50 chance of which conductor will open or have a loose connection.

I think the husband was OK and he couldn't argue as the lights were back on. I did hear from the wife during the process that "WOW this must be a big problem to take so long". I also think the husband had put in some time before giving up, he stayed close during the whole time, so he noticed that I wasn't just running up the clock. Also they are in the process of moving to a new house, having this type problem before closing just added to the overall anxiety. Knowing that you've got to break the circuit to see what's still working was a problem as the wiring wasn't too easy to map. I thought that I would have found the problem faster, but it ended up taking alot longer than I thought. Going forward I just wanted to reinforce that I didn't take too many missteps. P.S. they did have a few back-stabbed receptacles but this time they weren't the problem.

 

[e57]

~ Also they are in the process of moving to a new house, having this type problem before closing just added to the overall anxiety. Knowing that you've got to break the circuit to see what's still working was a problem as the wiring wasn't too easy to map. I thought that I would have found the problem faster, but it ended up taking alot longer than I thought. ~

What I do - if it is only one circuit - I shut everything else off. If it is more than one circuit - I'm dealing with feeders anyway... (You should have checked the panel voltages already, and the wire side of all of the connections. Making sure the problem is not right there in the panel.) I put a piece of blue tape at those items that still have power in the effected way (High/Low) - then I can turn everything else back on.

On occasion I will even enlist Joe Schmoe HO to help depending on the circuit affected - like outlets. With all but the two circuits in question off - hand him a flashlight, and cord with a halogen on the other end - looking for outlets with either dim or bright... (they feel like they are helping, and are... This is after I send them un-plugging everything in the house & moving furniture...) Then once you have a clue where all the affected outlets are - the ones in blue tape - open all of them and make a quick floor plan. Note which leg the outlet is on, and if the other leg is present. (Since you can affect voltage by adding or removing load on one leg, you can make it really obvious which leg is which the high one is one the low one the other.) Then you can start connecting the dots of how the circuit is run. Then ask yourself 'how you would have wired it' - and confirm that with what is there. Obviously the outlets that do not have both circuits present will not be where the 'problem' is.

Since you are looking for where they split, or before they split, in this type of situation. You can focus on them and follow the circuit back toward the panel. Load up one leg heavier than the other to get some good amperage on the neutral connection, and take temp readings of the connections, and take voltage readings of where the good neutral ends, and the bad neutral starts - someplace in there is where the problem is.

You should find one of two things - either an OPEN neutral - or a RESISTIVE one. The completely open one could very well be a cold connection, and won't seem to self-correct. A resistive one - with no load on it could cool enough to make the problem 'seem' like it went away - under unbalanced load - that one will be hot, or arcing, doing the snap crackle.....

Anyway - my point is I never trust the 'it just went away' answer. And will give the circuit some 'exercise' by loading it heavy on one leg then the other just to make sure... Because an evenly loaded, or unloaded circuit with a completely open neutral will look just fine voltage wise.

 

[e57]

One of our previous members here - who seems to have found another place to haunt... (Marc) Had the meter base version of this item, which we have discussed at length here before, and value it brings to the hunt for a lost neutral.

The Beast

I do much the same with my halogen lamps... A few others have mentioned using base-board heater elements...

 

[220/221]

In the first switch box I opened up the upstream neutral had voltage to ground, along with the ungrounded conductor.

That tells you that the neutral is open between that sw box and the source......right?

A simple resi troubleshoot like this shouldn't have taken nearly that long. I've had repairs take six hours but never a simple tshoot.

I think you jumped around too much.

A wiggy is the only tool you usually need on something like this.

There are only a handful of jboxes on a typical circuit. You knew from the first switch box that the issue was downstream. That shold have cut the number of possible places in half.

You said you had power at that switch box. 1) Turn off the breaker and see where the circuit goes. 2) Kill power going OUT of the sw box and you will know what outlets are upstream and which are downstream of that location.

If you believe in karma, send them a refund.