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I live in a older house ( 45 yrs ) with original wiring, knob and tube mostly. I have replaced most of the old wiring but some still remains.
I am blowing bulbs on one circuit ( house lights and low amp draw ).
By blowing bulbs, I mean anywhere from 2 minutes of use to 3 weeks. The fixtures are the older white ceramic style, ( this is an old wire circuit).
How dangerous is this situation? Would replacing the fixtures alone resolve the problem, or should I immediately re-wire ?
Will leaving the lights off until I have time to re-wire reduce any risks I am taking ?
Thanks alot
Kevin
Replies
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Kevin,
Your house is trying to tell you something, but you're not just not listening.
I would get this looked at/repaired asap.
Not using the lights should keep you safe, but only if the circuit is in good order. Better go remove the (30 amp?) fuse till repairs can be affected.
CT
*Kevin,One thing that can make bulbs blow too quickly is a disrupted neutral on the main service, but I don't know if that would rypically manifest itself on just one circuit.It seems entirely possible that it is a fire hazard, although I'm not an electrician.Personally, I'd immediately disconnect that circuit at the panel until the situation is rectified. (And verify that it's been de-energized by testing at the fixtures.)How many volts is that circuit actually carrying? 110? 220? FWIW, if you have knob and tube, the house is almost certainly a lot older than 45 years. I've never seen a post WWII house with K&T; in my area (NW Ohio) it dropped out of use in the 1920's or so.Bob
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Thanks for the help, the circuit is a 15 amp, 110 volt to a new panel with breakers. I live in Toronto and the house was built in the late 40's, with knob and tube for ( I think only the typical light circuits ) and somthing that looks like old loomex for higher draw ciruits, fridges, kitchen receptacles and so forth.
Thanks for your help.
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Kevin,
I'm amazed that knob and tube was still used after WWII. Sure about the age? Or is it just Canada?
*If it's the original fixture, that may be the problem. Personally, if I couldn't trace the exact/specific problem, I'd call in an electrician. Knob and tube, with wires in good shape, and fused properly is safe. I'd still plan on upgrading in the future. Sooner or later, the wiring will wear out, better safe than sorry. A good electrician will be able to access the situation and advise. As I said, it could be the fixture, it could be a splice in a nearby box, could be a splice nearby that's NOT in a box, could be the wire, could be the door slamming near the light. Could be alot of things. Definitely is something though! Don't just keep replacing bulbs. Jeff
*Kevin:"the circuit is a 15 amp, 110 volt" or "the circuit is _supposed to be_ a 15 amp, 110 volt"?I'd measure it with a meter, myself. If its way off, it could be the source of the problem and, if so, could be a hazard.Bob
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I am positive about the age, built just after the second world war, with some knob and tube, like I said in my earlier post, it looks like the lower usage circuits were knob and tube, and the heavier draws an early form of loomex.
Thanks for your help.
*Thanks for all your help folks, I have disconnected the circuit at the breaker and made sure the lights and receptacles are dead.Next step pulling down plaster !!ThanksKevin
*I am positive about the age, built just after the second world war, with some knob and tube, like I said in my earlier post, it looks like the lower usage circuits were knob and tube, and the heavier draws an early form of loomex.Thanks for your help.
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Well at least now you have an excuse to buy a Sawzall... :)
*Kevin:You probably know this but there's no need to pull down plaster. Easier to just abandon the old wiring and pull new with a fish tape.
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Kevin,
Something strange is definately going on here. I'm an electrical engineer, so I like to think I know a little about electricity.
Q1: Am I right to assume this is only happening on one circuit? It's not house-wide - old and new circuits.
Q2: Have you measured the actual voltage with a meter? If you're getting higher voltage that would definitely shorten lamp life.
Q3: Do you notice any flickering in those lights or are they brighter than they should be.
Q4: What is the ampacity of the circuit in question (fuse size)?
Old wiring alone will not kill your lights. You need higher than normal voltage or voltage spikes generally. However older wiring might contribute to these happenings.
Certainly replacing the wiring would be a good call if this is the only circuit that is behaving badly. Considering it's knob and tube, it's time to say so long to it. My only concern is that without first figuring out the actual problem, it might rear it's ugly head again!
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First, check with a volt meter and find out what you have at every point you can conveniently measure. Start at the service entrance. It's unlikely, but you utility company could be running hot. Here, they're required to provide nominal voltage +/- 5% at the service entrance. What is far more likely is that you have a 120/240 volt three wire system, and somewhere there's resistance in the neutral. That's usually just a bad splice, or a loose screw in the panel. You might start by making sure your neutrals are all clean and tight there.
-- J.S.
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Q1: Am I right to assume this is only happening on one circuit? It's not house-wide - old and new circuits.
Yes, only on one circuit, which is an old one
Q2: Have you measured the actual voltage with a meter? If you're getting higher voltage that would definitely shorten lamp life.
My tester is a heavy duty, but not digital. The testers scale is hard to determine the exact voltage, but it certainly is not 240, but I can't really tell if it is 115 or 105 either.
and
Q3: Do you notice any flickering in those lights or are they brighter than they should be.
No flickering that I have noticed, nor brightness either
Q4: What is the ampacity of the circuit in question (fuse size)?
15 amp breaker.
*It sounds like all the basic stuff checks out. The problem is within your house. We can bet it's not a utility problem or a main service issue because your troubles are isolated to one circuit.The actual voltage your fixtures are seeing is quite possibly not the true 120V they should be seeing, but without a good meter you won't be able to tell for sure. To be honest it probably doesn't matter. If there's a CONSTANT resistance in the circuit somewhere, you would actually get a lower voltage at the lamps. They would be slightly less bright, but it would actually give you longer life, not shorter.Don't get me a wrong - constant resistance isn't good. But I’m digressing.Here’s what I think is happening – somewhere you have a not so solid connection. What you probably have is something that’s not making good contact, and is instead creating a small amount of arcing. The arcing in turn puts bad stuff onto your line. The bad stuff might be in the form of varying voltages and frequencies. Your lamps should be seeing a nice smooth sine wave but are instead seeing something that’s choppy. The choppiness translates to greater than normal vibration in your lamp filaments – it manifests itself as physical stress on the lamp. The stress shortens its life.It’s just like when you work on your car – the more times you drop the trouble light on the floor, the quicker it seems to burn out!But what can you do? Old lamp sockets have been known to create such a problem. It’s possible replacing the fixtures will cure your problem. However it’s odd that all your sockets would be misbehaving at the same time. Since the lights are wired in parallel, arcing at one light should not have a big effect on other lamps on the circuit.Probably a more likely culprit is where the wiring terminates in the panel or at one of the numerous junction boxes. Put another way, good luck finding it. You could replace your light fixtures (not a bad idea anyway), but it’s probably time to rewire.If you suspect your lamp sockets, you could shut off the power and bend the bottom tab of the socket up a bit (clean off any darkness on the contacts with sandpaper). This should cure that problem (at least temporarily). Another test would be to plug in a newer table lamp into one of the receptacles on the circuit – does the table lamp also burn out quickly?Whatever you do, don’t screw around with it too long. Remember any arcing or other resistance in your line will create heat. It’s that kind of heat that causes bigger problems. What I’m saying is don’t burn your house down while you are looking for this problem.
*Thanks J Belcher.Kevin O'Donnell
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I live in a older house ( 45 yrs ) with original wiring, knob and tube mostly. I have replaced most of the old wiring but some still remains.
I am blowing bulbs on one circuit ( house lights and low amp draw ).
By blowing bulbs, I mean anywhere from 2 minutes of use to 3 weeks. The fixtures are the older white ceramic style, ( this is an old wire circuit).
How dangerous is this situation? Would replacing the fixtures alone resolve the problem, or should I immediately re-wire ?
Will leaving the lights off until I have time to re-wire reduce any risks I am taking ?
Thanks alot
Kevin