What would cause light bulbs to blow out (like a flame) and to be dim for a few minutes on certain circuits?

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I realize I need an electrician - but may I get advice first?
Two electrical phenomena: 1. Once every few months, I turn on a light and the bulb just blows out (like a candle). It goes on and then poof. You can hear it blow the filament. Obviously there is a voltage spike of some sort.
2. Every night, when I turn on the lights to two different circuits in the house, all the bulbs on that circuit are dim - like about 1/4th the normal brightness - and then within a few minutes, they all get up to brightness.
They are all incandescent bulbs and there is no dimmer on the circuit (that I know of). It's just a switch.
I realize both these things are weird and that an electrician needs to look at it - but is this normal stuff for an electrician to debug?
Have you ever seen these weird happenings? Why would they happen?
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On 3/21/2011 11:24 PM, Harold Lathom wrote:

Number 1., the electrician will laugh at. That is how bulbs usually blow. Thermal cycling, a thin spot in filament, and at some point the stress is just too much. The thin spot has higher resistance, gets hot, and melts, sometimes with fireworks, but usually just quietly breaks. No voltage spike needed.
Number 2. sounds like a bad switch or loose connection.
--
aem sends...

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Harold Lathom wrote:

An incandescent filament has a resistance which varies on it's temperature. When you turn on a lightbulb, the filament is cold, and has very little resistance to current. As such, when you first turn it on, it passes a lot of current.
As the filament ages, some areas on the filament become thin, and, like a fuse, will disintegrate with too much current, which you find when the filament is cold.
Jon
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On Tue, 22 Mar 2011 03:24:41 +0000 (UTC), Harold Lathom

Classic example of a loose neutral connection. One side of the line is getting low voltage (dim lights) The other side is getting higher than normal voltage. I bet the breakers for those two circuits are either right next ot each other or opposite each other in the panel (not always, but often). The low voltage wont hurt lights, but it can harm motors and electronics. The high voltage is on the opposite breaker and is very dangerous for electronics, motors, and can burn out bulbs in seconds.
I highly suggest calling an electrician ASAP and not using electronics as much as possible, and especially try to avoid heavy loads such as electric heaters, until this is fixed. Losing bulbs is a minor cost, but it could destroy computer, tv, microwave, fridge, etc. At least shut off the breakers to the rooms affected. If you have any electric skills, you might remove the panel on your breaker box and look for burnt connections, and tighten all the screws on all white wires (IF YOU CAN DO THIS SAFELY). Either way, dont delay getting this fixed ASAP. It's dangerous. Some circuits may get 220volts and do serious damage and even possibly start a fire.
I've seen this several times. I know someone who lost almost all appliances, christmas tree lights fried, and over half the bulbs in the house burned out.
I had it happen in my own garage when the neutral wire came loose on the service entrance to the garage due to high winds. I lost 6 CFL bulbs (one started burning but went out quickly on it's own), some outdoor flood lights and the sensors, several power tools that were I turned on before I know of this problem (and what alerted me of the problem), a battery charger that was plugged in, the garage heater blower motor and the garage clock radio that was plugged in. All because of one corroded loose neutral at the entrance head. (The garage is on a separate pole since it's far from the house)
One last comment, youy could measure the voltage on both the too bright and the dim bulbs with a multimeter. If it's only lights, screw in one of those old adaptors that turn a light fixtuure into an outlet. I always keep one of those in my electrical tools for that purpose.
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On Tue, 22 Mar 2011 00:08:32 -0600, jw wrote:

I will do that. I don't have handy the screw-in socket but I know what you mean and will pick one up at the hardware store. I have a Fluke DMM so that should be accurate enough once I get the socket setup. The lights are in the ceiling (which is tall) so it's a little cumbersome but I can wing it.
Thanks for the idea!
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** I agree with Jw, it is a classic loose neutral condition. If you are not electrically savvy get an electrician out. This is an annoying situation when it affects lights, but it can be very damaging if it affects motor loads
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Concur. Loose neutral. If you are comfortable working with high power pull the breaker panel cover and check the tightness of the set screws for the mains coming into the panel from the meter. In particular the bare wire. Use a plastic handled screwdriver. Otherwise call an electrician asap.
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On Mar 22, 8:38am, "Stormin Mormon"

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Yes, sometimes they are allen. You can use a platsic handled tool. That's easy to find for slotted set screws. Harder for allen. You can get T allens that have plastic on the grip end.
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On Tue, 22 Mar 2011 06:37:32 -0700 (PDT), jamesgangnc

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Upu can get allen bits that can be used on a 1/4" nutdriver with insulated handle. However, the OPs problem is more likely the neutral which is pretty safe to tighten with any tool. Most smaller panels like 100A panels use screwdriver slots, at least the older ones did.
From what the OP described, it sounds like it's only part of the house doing this. In that case, it's likely a neutral feeding a portion of the house, not the mains. Almost anyone with enough sense to shut off the main breaker can check and tighten the neutral screws on all the white wires in the breaker panel. But some people are afraid to go into a panel, and the problem could be somewhere downstream from the panel too.
I'm experienced and not afraid of going in the panel. If this was my problem, I'd inspect and tighten every screw in the entire panel, except the hot mains. Those I'd tighten too with the proper tools. If that did not solve the problem, I'd proceed to open every light fixture and outlet affected and check for loose connections of screws and wirenuts. That can be time consuming, but it's the same thing an electrician will do and could be costly.
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On Tue, 22 Mar 2011 17:25:21 -0400, "Stormin Mormon"

Fear is counterproductive. Respect is mandatory, when working with electrons.
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On Tue, 22 Mar 2011 17:25:21 -0400, "Stormin Mormon"

I thought you were the guy who had Jesus there to protect you? You should be able to grab one of the mains in each hand and Jesus will save you. Isn't that why you religion freaks say "Jesus Saves".....
So much for your beliefs. I guess I was right, the only purpose of christianity is to rob people of their money. There is no God, except the almighty DOLLAR BILL !!!!!
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On Mar 22, 6:05pm, snipped-for-privacy@myplace.com wrote:

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Just an fyi the neutral is not safe when it's floating. If it's floating then there is a voltage difference between it and the real ground you are standing on.
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ooglegroups.com...
Please see my other reply on this topic of tightening the main lugs hot. It is an extremely dangerous task that ought only be done by a properly trained and equipped electrician. Plastic coated tools are no substitute for insulated tools that are wielded by a trained electrician wearing arc flash protective clothing. Attempting to tighten the main lugs of an electric panel while energized can lead to serious injury or death! -- Tom Horne
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On Wed, 23 Mar 2011 09:10:41 -0700 (PDT), Tom Horne

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The power company will come out for free, and turn the power off long enough for you to tighten and inspect the connections.
The problem may be on the power company's connections. They will check their's at the same time.
Our electrical co-op service guy loaned me his 1/2 Allen wrench and propped up on the wall and watched me tighten my side.
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wrote:

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On Wed, 23 Mar 2011 19:45:37 -0700, Smitty Two

Agent version 3.3 is totally free News reader. aioe.org is a totally free server.
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wrote:

** I'll check them out.
In the NY downstate region, if you have an electrical problem, even one that's most likely a meter box or outdoor connection issue, you have to hire an electrician first. He diagnoses the problem and either does the repair, or if it is the utility companies domain, he contacts the power company to make the repair. If it is the power compaies domain, they will reimburse the customer for the electricians service charge.

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wrote:

** We aim to please
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On Wed, 23 Mar 2011 09:10:41 -0700 (PDT), Tom Horne

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Arc flash is an unlikely occurence working on a hot feed with no heavy loads turned on. When working on live feeds ALWAYS shut off all load breakers or pull all load fuses so there is no LOAD on the system while working on it. No load means no arc flash unless your tool connects between live and neutral or ground. Common sense and a bit of care - combined with the right tools, will prevent that from happening.
Obviously, it is best to shut off the main before working on the switched side - but it is also good to shut off the main before working on the LIVE side for the same reason.
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snipped-for-privacy@snyder.on.ca wrote:

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It would be a bit difficult to get arc flash in loose load wiring, where the current is limited to the load current.
You get arc flash by shorting a high current supply. It can occur downstream from a fuse or circuit breaker, but is worse on service wires. In a house, it could be from an allen wrench shorting H-N service wire terminals where there is likely 5,000 to 10,000A available for short circuit current, with minimal overcurrent protection upstream from the utility. The allen wrench vaporizes into a conductive plasma that can maintain the arc. Vaporized metal expands rapidly - an explosion. Heat can produce severe burns, as can vaporized metal condensing on you skin. And the explosion can produce shrapnel, like the remains of the allen wrench. You can get killed several different ways.
--
bud--

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