I realize I need an electrician - but may I get advice first?
Two electrical phenomena:
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.
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?
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.
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.
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.
** 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
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.
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.
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.
If you call the electric co you might get it all fixed for free. When I had power cutting out they found a loose connection outside and checked and tightened the circuit panel screws and found a few loose, all free. Its possible that bulb is getting 220-240, it can ruin most everything you have if thats the case. Unplug things till its fixed.
No. You can NOT cause a "voltage spike" by turning on a switch.
The voltage absolutely, positively can NOT and will NOT go any higher than the voltage being supplied to your panel by the electric company. That's generally between 108 and 122 Volts AC per leg.
If it's "A" light, as in any one of a number of different lights in your house, then it's normal. Bulbs wear out and blow.
If it's always the same light, at the same interval, and you keep replacing it from the same box of bulbs, then you probably have a bad batch.
That bulb that's been burning for 110 years in Chicago notwithstanding, bulbs have a finite life span, and it isn't very log.
That is a fire hazard. You've got a loose wire or a bad circuit breaker or a bad fixture somewhere. That kind of stuff burns down houses. Call an electrician ASAP.
On 3/22/2011 10:16 AM snipped-for-privacy@snyder.on.ca spake thus:
What the hell are you talking about? That sounds like nonsense, or at least hand-waving. How would a "voltage divider" result in the behavior the OP described?
I have no doubt that at least one of the problems he has *could* be an open neutral (which would be exceedingly easy to determine with a little probing with a meter), but so far none of the explanations I've read here would explain why the lights gradually come up to full brightness. That *is* just plain weird.
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.
Does it glow either normally or with excessive brightness, first? Or do you get nothing but the Big Blue Flash?
Are you sure these are not CFLs? There are some CFLs with regular shape bulbs over them. Look for a plastic ballast housing at the base (indicates CFL) or some low rated wattage typical of CFLs.
You may have an open neutral or an intermittently open neutral. This is a very serious problem, because some loads would get excessive voltage, leading to a possible fire hazard.
You may have a poor connection in the wiring - which is a fire hazard because the poor connection can seriously overheat. This poor connection may be intermittent, clearing itself up temporarily when it heats up. If this is the case, it is still a fire hazard.
Electricians can normally figure these things out and fix them.
Because if there is a loose connection, there is arcing (tiny sparks). Picture a welder welding steel. The more it sparks, the more it fuses together and makes a better connection. Also, heat will build up, and heat expands metals, which makes them fit tighter. But this heat can also start a fire.
You did check the light switch too, right? An arcing light switch can cause this. Why not just jump across that switch with a wire, or simply replace the switch, they're cheap. It sounds more like a neutral connection, but start with the easiest things first. Changing a switch is pretty simple. If it's not the switch, save the old one and you're only out a buck or two.
Do you understand voltage deviders and center tapped transformers? If the neutral (the center tap) is "raised" it becomes the center of a voltage devider, with differing resistances on either side causing a change in voltage side to side. A lower resistance on side A will cause a lower voltage drop, causing the voltage on side B to go up, and vise versa..
Also, as the load increases a "bad" connection on the neutral will heat up, and the connection CAN improve as the connectors expand - that's assuming the bulb lasts long enough!
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