Need help

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Oakey

Oakey

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New Jersey
I need some help guys,I went to a service call tonite for flickering lights in a house. When the microwave was being used the lights would dim, the circuit was one of the ones controlling most common areas of the house. I measured 25 amps on the circuit notably on a Federal panel 20 amp breaker. Opening up a junction box near the panel for the same circuit I could see that it was burnt and darn well hot to the touch. Out of the 3 leads out of this JB one was unusable as I stripped the insulation back almost 4 feet on the old BX to find it still dry and burnt and it was converted to 15 amp at this point. I have to rerun a new wire to replace it, hopefully not to far:confused: ... Maybe megger it?
Here is my question finally:
This Federal panel actually looked fairly new and with new breakers also, obviously this this shoud've tripped. Was there ever a newer Federal that was safe to use? These ppl just bought the house and I dont want to stir up a bees nest without accurate info about these panels. Gotta love the reds as ground...Btw the neutrals are in the panel above..
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Oakey said:
Interesting, what kind of draw would it take to burn the wire insualtion?
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Was there a loose splice? Because even small currents through a high resistance connection can generate plenty of heat. e/m
 
I like you not wanting to panic the owners but the fact is some older wiring and wiring that has been exposed to hacks and homeowners "might" be unsafe. I would casually ask them if they keep their smoke detectors checked and in working order. I wouldn't want to panic anyone, heck, old wiring has been working since it was installed but when I move into a place, renting, I buy a battery smoke alarm and hang it in the bedroom I'm sleeping in rather than trust that whatever is installed will work 100% of the time.
 
I'll ask them about a warranty but I'm just asking opinions before I spew out anything. Its interesting that maybe its a bad splice, even though the splice was burnt and welded the wires appeared tight however there were no wire nuts on them only tape, it smelled so bad. Its just that Ive never seen this much burnt insulation so far down a wire, it appears the whole run is bad.
 
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I've seen old BX short out like that when it draws damp. Was this installed in a damp place? The conductor insulation is sort of absorbant when it gets old, and it semi-conducts phase to neutral.
 
is the jacket on the bx rusty? ive seen the jacket get rusty, and if theres some sort of phase to jacket fault in the cable, insted of acting as a return path, the jacket acts as a high-impendance heater, sometimes glowing red
 
There appears not to be any dampness/wetness on or around the wire. Basement seems dry but its an old house. Ill check out more of the run to make sure. I really appreciate the advice. I guess my main concern is why this happened and how much of this wire could be affected
 
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id megger it and clamp my ampmeter on it while it has a load on it, and if it doesnt read 0 then the current is going somewhere else. just be creative and make sure that you're not overlooking anything
 
Usually you do see it burned 4' away. Ive noticed that a fault will burn towards the feed (in this case the breaker) not away from it. Is it possible that the BX was damaged before the "burn" started
 
jamesguy10 said:
id megger it and clamp my ampmeter on it while it has a load on it, and if it doesnt read 0 then the current is going somewhere else. just be creative and make sure that you're not overlooking anything
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Ok I will Thx!
jrannis said:
Usually you do see it burned 4' away. Ive noticed that a fault will burn towards the feed (in this case the breaker) not away from it. Is it possible that the BX was damaged before the "burn" started
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It does not appear that is was but it was respliced at one point. This makes perfect sense guys a 4 ft + burn is just new to me. Its easy to blame Federal but would any other breaker sense something like this?
 
mdshunk said:
Hey, a good 20 amp breaker of any brand will hold 25 amps for a good long while. Hours, I'd suspect.
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I wouldn't say a "Good" one, but many will it's true - hold even more for longer. But a "Good" one should trip in ~ 15 minutes or less at 20 IMO.

I have also seen Fed Pac 'Stab-loc's' hold enough for long enough to have the conductor act as a fuse. I have little trust for the brand, and you won't find many who do.... (The switch gear was OK - but load-centers were garbage) IMO they are a poor design, and equally poorly made. Also the alloy used for buss-work and neutral bars and lugs were of an intemediate AL alloy that would sometimes cause dissimular metals type break-downs at terminations. Often I use the breaker cost - propensity for failure and liability as grounds for a panel up-grade. Gut it in place, and use a 2"+ nipple into a new one. Sure it's a cheap sleazy labor saver panel swap - but I feel better with a better breaker....
 
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