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I have an 100 year old house that has one lighting circuit that controls most of the ceiling lights in the entire house. Yesterday all lights on that circuit stopped working so I checked the breaker but it was not tripped. I pulled a three way switch to check for power at that location (using a Fluke VoltAlert) and found out that not only was there power at that box but I would get an alert if I moved the tester anywhere within 4 inches of wall (up to 3+ feet away from the box). Seeing as the minimum reading to activate the VoltAlert is 90 VAC I am guessing I have a melted/ broken/ damaged hot wire somewhere in the wall that is touching the inside of the wall. I have since turned off the breaker and want to start troubleshooting the circuit tonight.

The circuit only has a hot and a neutral. There is no seperate ground.

Why didn't the breaker trip?

I am guessing that I need to figure out where power is fed from then check for continuity between each wire from fixture to fixture to see where there may be a break? If so then open up the wall and replace the wire?

Any other possible senarios to cause this type of issue? Thanks.
 

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all lights on that circuit stopped working
the breaker . . .was not tripped.
Why didn't the breaker trip?

There was no short or the breaker is bad, either one or both.

Any other possible senarios to cause this type of issue? Thanks.
Breaker contacts have failed to an open state?
Try slamming the breaker handle on and off a few times. A guy at the electric supply counter did this once, which taught me something and saved my customer $38.
 

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First I'd try slamming the breaker like yoyizit said. (no, don't hit it)

What you need to do is check for voltage with a multimeter, I do not trust those touch meters. It could be a bad splice...have you done any drilling, nailing, working in the attic, etc.?

The wall (assuming it is sheet rock) can't conduct electricity unless you put 7.2 kv trough it or something, thats 7080 more than your standard outlet voltage!
 

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Jeez how many times does this problem occur? 4 or 5 a month on this site maybe more.

If you have power present in your electrical device boxes but nothing works you have an open neutral in the branch circuit somewhere. In this case it sounds like he has lost the entire branch circuit. So his open is between the first device box on the circuit or junction box and the panel.
 

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Very true and he has no equipment ground to trip a breaker so it is possible that he is faulted to the metal lathe and lost the hot to the circuit. I would check to see if I had power in some of the other boxes on the circuit. If so I'm still betting on open neutral. But it sure sounds like the metal lathe might be energized. I didn't catch the 3 foot from the box statement.
 

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Oh, I didn't catch the 3 ft away part...is there any chance you could shut the circuit off and carefully chip away some plaster to get to the lath? Then use a multimeter to test between the lath and a neutral.

I do not recommend anyone looking in the panel while its energized! Unless they are experienced and comfortable with electrical work.
 

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Before tearing open your wall, I would suggest testing other switches and see what you get. Also trace wiring in the attic/basement if you can.

The wiring should go in some logical manner from one device to the next. So you would get power up to a certain point, then no power.

If you verify that power is in fact lost at that point and the wire is not going into another wall on the back side of that wall or terminating on the back side of that wall at a light fixture, etc., then maybe there was a splice in the wall at that location.

This was common with knob and tube wiring, although all the splices I have seen were done quite well! But who knows what someone else might have come along and done later (inside the wall).

FYI - A circuit breaker will only trip if there is a short. Not if a wire breaks.
 

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but I would get an alert if I moved the tester anywhere within 4 inches of wall (up to 3+ feet away from the box)
About the voltage detector, static charge can set them off. I have those white plastic tables with folding legs, and if I move my voltage detector across the plastic surface, it goes off.

Without knowing more about the situation, you should assume it's a true reading though, until proven otherwise. Best to be safe.
 

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I carry a light stick (fluke non contact AC detector) in my pocket all the time, but I don't use it to troubleshoot. If you were testing it at a 3 way switch, both of your travelers will always set it off, and both sides of any switch leg (once you get used to this you can figure it out by spreading the wires apart and seeing which one lights up first). The cable doesn't even need to have any power on it and your light stick will go off if it is run next to (bundled) another cable for any length (induced voltage).

The point about "3 feet away" I wouldn't worry about either because you might be reading the cable feeding the box through the wall.

Sometimes you can put it close to the conductor, get it to light up, and then pull it much farther away and it stays lit.

In other words, nobody can give you a true answer, without guessing, as to what is really going on until you get a "contact style" tester and check the circuit out.

Go and get yourself a solenoid style tester if you're going to do any electrical work.

Now I know you're going to go out and get a Digital multimeter because it looks much cooler, but you're going to have the same problem because the "Dead" leg will still show a voltage only a few volts less, or you're going to see 115 and then miss the little "mv" next to it.
 

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Now I know you're going to go out and get a Digital multimeter because it looks much cooler, but you're going to have the same problem because the "Dead" leg will still show a voltage only a few volts less, or you're going to see 115 and then miss the little "mv" next to it.
:laughing: That never happens with my analog!
 

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One of the best industrial electricians I've ever worked with did the little "mv" error many times. The guy was practically a genius when it came to troubleshooting, but I guess because he was always in such a hurry he missed those little things some times. That's why most maintenance electricians keep the fluke in the shop on the bench.
 

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I missed the "analog" part, You really are old school. Cool :thumbsup:
I keep meaning to get around to buying one of those fancy auto-scaling digitals, but I never get a round-tuit. So I have cheap digitals that I hate and a nice analog that I love. :)
 

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Discussion Starter #16
Update

First off thanks for the input to date. So here's where I am at so far. The walls are actual plaster over wood lathe (not metal). I swapped the breaker with an extra new one I had on hand and there was no change. I then proceeded to trace how the wire was run throughout the basement. It went into a metal junction box and is secured with wire nuts. Tested with a Fluke digital multimeter and read 120VAC (actually 119 and change). Then it ran uniterupted into what looks like an old, original fuse panel (metal box about 12" square 3" deep with a D-ring pull to open the box). Tested at that point and had 120VAC.

Now it gets interesting. In the old fuse panel it is connected to the classic knob & tube cloth sheathed wire that heads up to the first floor. The closest outlet box that is not working is about 6 feet or so away from were the other wires are fed up from and is the end of the run (only 2 wires enter the box). So I know that the feed probably heads up to the ceiling fixture first and then goes from there. I have not pulled that fixture yet as I had go to work the rest of the weekend.

Issue #2 that has come to light from working on this is the amount of items fed off of this circuit. The list is as follows: Living room light, living room outlet, parlor light, dining room light, 1st floor bedroom light, 1st floor closet light, stairwell to 2nd floor light, 2nd floor office closet, 2nd floor hallway light, 2nd floor bedroom lights (3 seperate bedrooms), 2nd floor closet lights (2 closets), and all 2nd floor bedroom outlets (6 total). I'd say too much for one 15A circuit to handle.

The items on the 2nd floor were from an attic remodel in the mid 1950's. I am guessing that they fed everything off of a single attic light and more than doubled the load on the circuit. Even if I can find what the issue is it may not matter as I am guessing rewiring these spaces may be a must.

Thoughts? Next steps? Is it time to start cutting openings in the walls to feed new circuits?
 

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First off thanks for the input to date. So here's where I am at so far. The walls are actual plaster over wood lathe (not metal). I swapped the breaker with an extra new one I had on hand and there was no change. I then proceeded to trace how the wire was run throughout the basement. It went into a metal junction box and is secured with wire nuts. Tested with a Fluke digital multimeter and read 120VAC (actually 119 and change). Then it ran uniterupted into what looks like an old, original fuse panel (metal box about 12" square 3" deep with a D-ring pull to open the box). Tested at that point and had 120VAC.

Now it gets interesting. In the old fuse panel it is connected to the classic knob & tube cloth sheathed wire that heads up to the first floor. The closest outlet box that is not working is about 6 feet or so away from were the other wires are fed up from and is the end of the run (only 2 wires enter the box). So I know that the feed probably heads up to the ceiling fixture first and then goes from there. I have not pulled that fixture yet as I had go to work the rest of the weekend.

Issue #2 that has come to light from working on this is the amount of items fed off of this circuit. The list is as follows: Living room light, living room outlet, parlor light, dining room light, 1st floor bedroom light, 1st floor closet light, stairwell to 2nd floor light, 2nd floor office closet, 2nd floor hallway light, 2nd floor bedroom lights (3 seperate bedrooms), 2nd floor closet lights (2 closets), and all 2nd floor bedroom outlets (6 total). I'd say too much for one 15A circuit to handle.

The items on the 2nd floor were from an attic remodel in the mid 1950's. I am guessing that they fed everything off of a single attic light and more than doubled the load on the circuit. Even if I can find what the issue is it may not matter as I am guessing rewiring these spaces may be a must.

Thoughts? Next steps? Is it time to start cutting openings in the walls to feed new circuits?
It is code to have all of that on one circuit. So its ok, but probably not satisfactory if your tripping breakers all of the time.

First off, check the old fuse panel...maybe a fuse is blown, it happens...

If that doesn't work, cut the power and open that close outlet, what does it look like in there? Check some of the switch boxes. You might just find a burnt connection.

Always test even if you assume its dead.
 

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Discussion Starter #18
Found the Problem

I found the problem (only had to cut one hole in the wall and two in the ceiling to find it). I backfed power through one of the outlets on the circuit while the breaker was off using a length of 14 ga. NM (plugged it in directly to a good circuit). Found out that the issue was between the first light fixture and where the circuit was fed from the basement. It turns out the first splice for the neutral was not making good contact. I removed all old tape and cleaned the wires thoroughly. Insulation looked good so I just used some linesman's pliers to crimp down the wires, soldered the connection and retaped with heavy gauge 3M electrical tape. Now we're back in business.

I still can't figure out why the probe tester gives false readings though. Maybe something to do with lack of a true ground? Oh well.
 
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