What Causes My Lights to Dim?

Old 10-02-03, 07:19 AM
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What Causes My Lights to Dim?

I recently purchased an older home (1952). I have not added anything to the electrical circuit. The system was previously upgraded. There are breakers (4) that contral the whole house inside and a panel outside. There is a detached garage that has electricity run to it via gray pipe and that circuit checks grounded.

Most of the wiring runs overhead but there is a green 600 volt wire running under the house that was for a window unit and previous owners added a bathroom and some of that wiring runs under the house (conventional floor with about 18" of crawl space.

The main house has one 3 prong plug that is grounded but the rest are all two prong. The main breaker says it is a 100 amp system. Is there an easy way to determine the gauge of wire in each outlet? Existing wire is black and white wrapped in black asbestos looking covering.

Here's the problem: when I run more than one circuit the lights dim considerably, almost a brown out situation. Would this be a grounding problem, an amperage problem, too many circuit on one breaker, or possibly a faulty breaker?

I do not plan on fixing the problem myself. I just don't want to end up paying for work on a recommendation when I'm really ignorant on the subject.
Old 10-02-03, 07:53 AM
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Is there an easy way to determine the gauge of wire in each outlet?
With experience, you can recognize wire gauge by looking at it. In the meantime, perhaps you can just go to Home Depot and buy one foot of each gauge wire to use for comparison.

Do your lights dim and stay dim, or just flicker (dim and rebrighten)? Dimming lights can be caused by overloaded wires, overload transformers, or bad connections (but not usually bad grounding or a bad breaker). The problem might be on your side or on the power company's side. I usually recommend that you first ask the power company to check out their stuff, since if it is their problem, it can be fixed with no money on your part. If the power company says that their side is okay (or refuses to check it out until an electrician says your side is okay), then call an electrician. He'll probably start by checking the connections in the panel.
Old 10-02-03, 08:59 AM
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I had something like this once in a new home...came home one day. Noticed that the airconditioner compressor was cycling on and off, over and over. When this occurred, the lights were also dimming at the same time.

Went to the electrical panel and smelled smoke. I took the cover off and found that many of the return wires were loose at their binding posts. The wire involved with the airconditioner had the insulation burned all the way up inside the wall and had destroyed the conductor.

The energy has to go somewhere, if it's not being consumed by the devices, it's lost in connections or cables.
Old 10-02-03, 05:48 PM
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What Causes My lights To Dim?

Maybe I need to do more tests on all the outlets. When the blower for the AC/Furnance comes on the lights dim and stay dimmed until it kicks off. Also, when using a high wattage applicance (shop vac for example) the lights dim and stay dim.

I'm rehabing the property and it seems that my air tank does not run at full speed. If the air tank is running and I turn on the shop vac you can hear the air tank really slow down.

I'll check to ensure the panel is screwed down tightly. I also remember someone who lost a panel becuae the screws were loose and a few wires burned.
Old 10-04-03, 05:04 AM
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too much load -- motors not running fast enuf due to low voltage. air compressors draw lots of amps -- part of problem could be too small of wire/ cord to larger motors.
Old 10-04-03, 07:30 AM
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This really sounds like a feed problem. Either the POCO or you portion of the feed might not be tightened correctly. If you do not now hot to work hot or pull the meter, call an electrician. Grounding would not produce this kind of problem. You could find circuits on opposite sides of the nuetral and see if any lights get brighter when you turn on a load. That would indicate a nuetral problem.
Old 10-04-03, 11:12 AM
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Bottom line is, this could be a possible fire waiting to happen. I would have it checked out as soon as possible.
Old 10-04-03, 07:30 PM
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Lights Get Brighter

I did do some more testing and there are some lights that do get bright when an additional high wattage load is turned on (vac or air compressor).

I'm going to call the electric company and have them check their connections. I did notice that the stringer cable was not connected to the riser and I think the power company will take care of that.

I really appreciate the input. I know how to wire circuits but the panel scares me.

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