jamlove
Oct 2, 2006, 08:56 AM
Hello all, hope you can offer some trade secrets and help me out here...
This weekend I helped a friend add a light fixture in his remodeled basement. The project was simple and straightforward (ha ha ha). A hole in the wall exposed a modern 12/2 line feeding an outlet. We removed the outlet, and used that supply line as the power to the switch, which controlled the new fixture.
After wiring everything, I turned the power back on and tested the light. It did not work.
Turned the power back off and double-checked all my wiring. Everything looked OK. So I turned the power back on, and asked my friend if he was sure that outlet we'd removed DID work. He said yes. But I thought I should test for voltage at my new switch. Since my voltmeter is lent out, I did an ill-advised test: touching hot to ground with power on.
The first test, hot to ground, NOTHING happened. I thought "oh, we don't have power here after all". But then I tried hot to Neutral, and it sparked and popped the breaker.
So now I knew:
1) the circuit, even though it has a ground wire, is not properly grounded.
2) we DO have voltage at our switch, so the light fixture must be messed up.
Anyway, I turned power back off, rewired my light fixture (flourescent) again, and found that my neutral wasn't on as good as it should've been. Probably why it didn't work. I twisted it on much better, knowing it would work now.
Turned the breaker back on: nothing.
But NOW, the outlet and lights on the same circuit weren't working either! They had been before we started.
So I thought: I've blown the breaker. It must be old and that was its last trip.
Went and bought a new breaker. These are modern Seimens breakers, but note: the house was originally Knob & tube, and some of it is still there.
The new breaker did not work, but after installing it we discovered another outlet on the same branch (hadn't checked it before) which WAS working.
So now we did a THOROUGH survey of the whole basement room, mapping the whole branch. We found that there are a total of 4 outlets and 2 fixtures (including my new one) on this branch. Only one outlet, the one closest to the power panel, is working. The others are dead.
This is where it got UGLY. I started cutting exploratory holes in the walls, since this basement was totally finished out. I discovered what you've probably just guessed: Junction Boxes hidden under the drywall! Junctions from old knob & tube ALUMINUM wire to newer 12/2. This renovation appears to have been done years before the basement was finished.
Anyway, after cutting seven holes in the walls and tracing as far as I could, I found the box where two lines exit: one goes to the working outlet on the branch, and the other exits toward the side of the room with all the non-working stuff.
The best part: We CANNOT access that box. It's an old exterior light, which is now covered by vinyl siding!! And I can't reach it from the interior, it's in a crevice.
Here's another fun thing about the remaining three non-working outlets: One is wired BACKWARDS, and all three are TERMINATIONS. That is, each of their boxes only has one set of wires coming in. THis means they are not connected in series, but rather a kind of hub-and-spoke type of thing... they must have multiple other hidden Junction boxes!!
MY QUESTION: (Help!) how do I find out what went wrong?
When I shorted the circuit, I blew something OTHER than the breaker. This worries me because it's not supposed to happen that way, right?
With the evidence I've found so far, it's clear that somebody was lazy, inexperienced, and DID NOT get a permit to do the electrical work. There's no way it would have passed... there are Free-Floating wires up in the ceiling, terminated with nipples, just laying there going to nothing. There are ungrounded circuits. Hidden inaccessible J-boxes.
Anyway: do I just need to keep cutting holes until I've exposed EVERY junction box, then open them all and find out what melted or popped off or what? Is there a trick?
Or, should I take this opportunity to rip all this junk out and run a brand new 12/2 all the way to the panel?
NOTE: I was worried about a shared neutral being blown out someplace not even on this branch... but everything else in the house currently WORKS. No other branches seem to have been affected (although a lot of them seem to be wired in a similar way)
Any tricks of the trade are really appreciated, and I thank you for reading all of this. I figured you guys must run into this sort of thing regularly.
Many thanks,
James
This weekend I helped a friend add a light fixture in his remodeled basement. The project was simple and straightforward (ha ha ha). A hole in the wall exposed a modern 12/2 line feeding an outlet. We removed the outlet, and used that supply line as the power to the switch, which controlled the new fixture.
After wiring everything, I turned the power back on and tested the light. It did not work.
Turned the power back off and double-checked all my wiring. Everything looked OK. So I turned the power back on, and asked my friend if he was sure that outlet we'd removed DID work. He said yes. But I thought I should test for voltage at my new switch. Since my voltmeter is lent out, I did an ill-advised test: touching hot to ground with power on.
The first test, hot to ground, NOTHING happened. I thought "oh, we don't have power here after all". But then I tried hot to Neutral, and it sparked and popped the breaker.
So now I knew:
1) the circuit, even though it has a ground wire, is not properly grounded.
2) we DO have voltage at our switch, so the light fixture must be messed up.
Anyway, I turned power back off, rewired my light fixture (flourescent) again, and found that my neutral wasn't on as good as it should've been. Probably why it didn't work. I twisted it on much better, knowing it would work now.
Turned the breaker back on: nothing.
But NOW, the outlet and lights on the same circuit weren't working either! They had been before we started.
So I thought: I've blown the breaker. It must be old and that was its last trip.
Went and bought a new breaker. These are modern Seimens breakers, but note: the house was originally Knob & tube, and some of it is still there.
The new breaker did not work, but after installing it we discovered another outlet on the same branch (hadn't checked it before) which WAS working.
So now we did a THOROUGH survey of the whole basement room, mapping the whole branch. We found that there are a total of 4 outlets and 2 fixtures (including my new one) on this branch. Only one outlet, the one closest to the power panel, is working. The others are dead.
This is where it got UGLY. I started cutting exploratory holes in the walls, since this basement was totally finished out. I discovered what you've probably just guessed: Junction Boxes hidden under the drywall! Junctions from old knob & tube ALUMINUM wire to newer 12/2. This renovation appears to have been done years before the basement was finished.
Anyway, after cutting seven holes in the walls and tracing as far as I could, I found the box where two lines exit: one goes to the working outlet on the branch, and the other exits toward the side of the room with all the non-working stuff.
The best part: We CANNOT access that box. It's an old exterior light, which is now covered by vinyl siding!! And I can't reach it from the interior, it's in a crevice.
Here's another fun thing about the remaining three non-working outlets: One is wired BACKWARDS, and all three are TERMINATIONS. That is, each of their boxes only has one set of wires coming in. THis means they are not connected in series, but rather a kind of hub-and-spoke type of thing... they must have multiple other hidden Junction boxes!!
MY QUESTION: (Help!) how do I find out what went wrong?
When I shorted the circuit, I blew something OTHER than the breaker. This worries me because it's not supposed to happen that way, right?
With the evidence I've found so far, it's clear that somebody was lazy, inexperienced, and DID NOT get a permit to do the electrical work. There's no way it would have passed... there are Free-Floating wires up in the ceiling, terminated with nipples, just laying there going to nothing. There are ungrounded circuits. Hidden inaccessible J-boxes.
Anyway: do I just need to keep cutting holes until I've exposed EVERY junction box, then open them all and find out what melted or popped off or what? Is there a trick?
Or, should I take this opportunity to rip all this junk out and run a brand new 12/2 all the way to the panel?
NOTE: I was worried about a shared neutral being blown out someplace not even on this branch... but everything else in the house currently WORKS. No other branches seem to have been affected (although a lot of them seem to be wired in a similar way)
Any tricks of the trade are really appreciated, and I thank you for reading all of this. I figured you guys must run into this sort of thing regularly.
Many thanks,
James