This will be a long explanation of the problem but necessary. I REALLY need some help.
An HO asked us to upgrade his electric service to 200A and to move the panel to a new location. The house is all knob and tube wiring. It has a total of 3 circuits that I’ll call 1, 2, and 3 respectively. WE installed the panel and and ran extension wires over to the old panel location which was an old fuse box. We removed the fuse box, installed a j-box and tied into the new extension wires.
A word about the old fuse box. It was one screwed up mess. I could not figure it out, nor my partner. The electric company came out and was baffled. The HO was getting an electric bill but it appeared that at least one of the circuits was bypassing the meter and was directly tied into the utility drop wire which the electric company engineer confirmed was the case. He said it looked like it had been jumpered in some convoluted mess in such a way that the circuits obviously were working but he didn’t know how and he said for years someone was getting free electricity (the wire drop to the house was 10 ga. wire going into a 30A fuse box) buy jumpering directly to the drop wire, it wasn’t even fused.
So anyways…We hooked up circuit 1 which was a wire the fed the basement and had a black/white and no ground, it wasn’t romex but color coded at least. That circuit worked fine. Circuits 2 and 3 are knob/tube. I had a total of 4 wires remaining to be junctioned which to me was a hot/common for each of the two remaining circuits. Because of the fiasco jerryrigging in the fuse box we could not determine which of the two wires for circuit 2 was the common wire, so I junctioned up circuit 2 to the black/white extension I ran by taking a guess. I turned on the circuit and it worked (as it prob would as there is NOTHING in the house but a few switches and old style recepts, so nothing required polarity here). I next did the same thing to circ 3 again not sure which was the common wire, so I guessed again. I then went to the main panel to hook it up there. As soon as I touched the white wire to the neutral bar Circ 2 tripped, but I was working on circ 3. The white wire was hot. So knowing that in knob/tube there is a common wire that all circuits would be sharing I reasoned that I had the wires for circ 3 backwards in the J-box. So I reasoned I guessed wrong when I junctioned 3 to the extension, I went back over and flip flopped the two wires. This time the white wire didnt’ trip the breaker. It was only until inserted the black into the circ 3 breaker and flipped it on that the circ 3 breaker would immediately trip. So I thought, ok, I must’ve guess wrong when I junctioned circ 2 so I flip flopped circ 2’s wires. Bam, same problem, this time Circ 3 would trip.
Now, there are only 4 wires here, that represents only 2 combinations so at this point I”m baffled. I decided to unjunction all 4 knob wires in the j-box. I then took a hot wire from circ 2 and tied it to one of the knob wires leaving the other 3 exposed and turned it on. I put my tester on each of the 3 bare knob wires and touched the other lead to the ground wire in the j-box. I read 120 on all 3 bare wires. I wasn’t expecting to see that, I was expecting to see at least 2 dead wires. So I next removed the hot from the one knob wire and moved it to one of the other knob wires and repeat the test. Same thing, all 3 remaining bares were hot. I repeated this same test again for the 3rd and 4th bare knob wires, moving just one hot to it. Every time the one hot wire energized all 3 bare wires. I couldn’t understand that. To me that suggests that in the knob/tube wiring throughout the house that they crisscrossed somewhere the common over to the hot. If you’d see some of the rigging in this house you might conclude that yourself. But since the wires aren’t coded you can’t tell which is the common vs. hot. The house is gutted mostly, 90% of the knob/tube is exposed thru the house. It’d be easy to trace except for a few places it goes hidden and you don’t know what it does beyond your view.
Any advice, ideas on what is going on? I understand knob/tube mostly, maybe not fully. They’d run one hot wire throughout and jumper off it to feed lights and switches, etc. They’d run a single common all over to bring the current back, tapping onto it as needed. When they’d add another circuit they’d do the same thing. It’s not unlike wiring today except that our wires are as a cable together whereas theirs are run as separate conductors. Any help is appreciated, and if I’ve done something dumb here I’m up to being told and corrected. Fortunately the house is abandoned, the power doesn’t need on, so now it’s off, and I’ll resume troubleshooting Monday.
Edited 1/20/2007 8:59 am ET by WillieWonka
Replies
I suspect that the circuits are paralleled -- hot to hot, neutral to neutral. Any lightbulbs or other loads on the circuit will then make everything appear hot if you "hot" one wire. You need to disconnect all the loads and ohm it out.
BTW, check the fuses that were in the old box. Likely both hot and neutral are fused. Odds are that at least one fuse was blown, even though everything in the house was working.
I'm not sure what you mean by "paralleled" hot to hot neutral to neutral. I mean, I understand parallel wiring if that is what you're saying, I prob understand it if you clarified what you mean. Are you saying that if I have just one fixture, such as a light bulb turned on, that it can somehow make all the others look hot? I should make sure everything is turned off or something?
Maybe I do understand what you're saying. You're saying that the two circuits initially start out as individual circuits and are fused as individual circuits, but that somewhere down the line they're joined together in essence forming a single hot thru the house? That'd be weird because if you drew too many loads after they joined later on which fuse would blow?
This is 14ga wire, the fuse box had 30A fuses on these wires. None of them were blown. Obviously they were blowing fuses as their needs increased and kept putting in higher amp fuses to solve it. I understand that was common practice in those days. If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
Yes, with a case like this you can get into danger assuming that everything else is right except for trying to make the connectsion at the panel.Switch neutrals where not unknow.Like wise it was not unknow for the hot connection to be on one circuit and the neutral on another.And then you don't have any ideas of what kind of strange changes might have been make along the way. Thinks just to "make it work".Step by step ohming and signal tracing the wires is needed..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
> You're saying that the two circuits initially start out as individual circuits and are fused as individual circuits, but that somewhere down the line they're joined together in essence forming a single hot thru the house? That'd be weird because if you drew too many loads after they joined later on which fuse would blow? Yep. K&T wiring was pretty much the wild west -- whatever worked was "legal". And fuses were for wimps, as you found with the bypassed circuit.It would not be at all unusual for a fixture to draw its "hot" from one circuit and its neutral from another, especially a switched fixture. The "electrician" just looked for two wires at opposite potential. And don't even think about 3-ways.When you "hot" one wire and leave the rest disconnected, any lightbulb on the circuit will present about 100 ohms load, pretty much a short circuit when compared to the thousands of ohms load your voltmeter represents. The voltage on one side of the bulb might measure 5 volts lower than on the other (depending on the size of the light and the sensitivity of the meter), but that's pretty much "noise" in most cases.Actually, for K&T #14 wire may have been legal at 30A. Remember that the current capacity of a single wire is significantly higher than wires in cables, and no one back then worried about safety margin -- so long as it wasn't smoking it was safer than gas lights.
Half of the harm that is done in this world is due to people who want to feel important. They don't mean to do harm but the harm does not interest them. --T.S. Eliot
At the risk of appearing snide, this is the sort of job that really needs to be done by an electrician, and is best discussed in an electrical forum. There are several out there; one might start at electrical-contractor.net or electricalknowledge.com
Pennsylvania, I believe, does not license electrical contractors. Just because something is 'legal' does not mean it's wise.
As for this problem house .... I would consider a bypassed meter to be a major sign that some illegal work was done. There is no way of telling what else that hack may have done.
Knob & Tube, while not automatically a bad thing, is certainly old enough to have had many changes and repairs performed, usually by unqualified people. This, and the lack of a ground wire, makes any K&T home suspect, probably in need of a complete re-wire.
Your next step ought to be to map out every outlet and appliance in the house, then see which circuits power what places. Do it one circuit at a time, checking ALL places each time. This will help you find any connections between circuits.
The most likely cause of this problem is a mis-identification of the old wires. You may be energizing a neutral, mistaking a 'hot' wire for a neutral, or trying to feed the same circuit from two breakers.
BTW, I do hope you added a ground rod in this upgrade.
Actually, I added two ground rods in order to pass inspection, spaced 6 feet apart with #4 solid bare copper.
I have done a lot of electrical work, consider myself pretty experienced among the best of them when it comes to residential. However, I from time to time come across something I'm not sure of, and I'll troubleshoot to some degree and then realize I need to seek advice from someone who may have more experience. That is why I come here from time to time to seek answers. Not only is this a problem, but it is an opportunity to learn and grow my experience and make me all the better at doing electrical work when I do my home improvements. If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
Thank you for being gracious. We all get puzzles tossed our way from time to time, and for every task there is a 'first' time. Please note that my reply before was addressed to "all." The tendency for ambition to exceed ability seems greater where there is neither regulation, nor systematic training. Troubleshooting is one area where simply having 'run wire before' is not enough education. Anyone who works with electricity has had the 'pleasure' of sorting out messes made the "self taught." That's also one of the reasons I suggested the professional electrician web sites. There is a limit to what the well meaning handyman should do. Fine as this site is, it caters to a lot of folks whose electrical work is minor, and they might be misled by posts they did not properly understand.
I'm curious, why would you want to keep reusing knob and tube, historical restoration?
I agree, if it were my own house, I'd start from scratch and not re-use anything.
That's what my brother is doing with the house grandpa built in 1907, electricity added in '15 or so. Going to 100% new wiring.
3/4 of the time the wires were run inside the old gas light pipes.
Grandpas fuses were commercial electrical ceramic boxes of the time with pieces of solder between screw terminals. Cheap to replace anyway.
The HO inherited the house from his father who died. His father just lived in an old old house. The HO is planning on doing a complete rewiring. However, there is a sewer project going in and the township was forcing the man to hookup to it now. He requires an upgrade because the sewer pump uses electricity and he had no way to expand the old fuse box. The HO has most of the house gutted, it's a putzing arouind house for this man as he is retired, and he is slowly remodeling it. No historical renovation factors exist really, it's just that he is taking his time and only doing the upgrade for the panel now because the township is forcing him to.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
"However, there is a sewer project going in and the township was forcing the man to hookup to it now. He requires an upgrade because the sewer pump uses electricity and he had no way to expand the old fuse box."FWIW I like in place that had an old sewer lines installed when the place was developed in 1928 for SUMMER cabins around a lake.Of course now the homes are big and full time and the old lines where overload and in mayplaces completely deteriated. And houses have been build over them.So a new force main system was installed with sewer grinder pressure pumps at each house. They where in a tank in the yard.Because the homes electrical systems varied from 60 to 200 amps and no idea of what the inside panels where like the city worked with the power company and they tapped into the meter box PAST THE METER and feed a control box or disconnect with a 2 pole 20 amp breaker then to the pumps.Not that it has anything to do with your problems, but to show that there are other unusual systems out there..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.