Lights Dimming, Main Breaker Buzzing

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Old 11-09-13, 07:02 AM
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Lights Dimming, Main Breaker Buzzing

I've noticed for the past year or so that the lights dim whenever there is a significant load on any of the other circuits. For example, my wife was running a portable heater and her iron in the basement last night, and the recess lights in my daughters room were dimming. I also noticed this morning that the main breaker is buzzing. The panel is original to the home (30 years old). Is it possible to replace only the main breaker on such an old unit, or should I just replace the entire panel, which I planned on doing eventually anyhow. Panel is a Gould 2040MB1200 (200 amp service).
 
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Old 11-09-13, 07:09 AM
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Notice any of the outlets not working?
Got a picture of this panel with the cover off.
You have a potently very dangerous situation then and this should have been address long ago!
Loose wire, loose or lost or loose neutral in the incoming power, under sized wiring, all can cause a fire.
Time for a real electrician to come to take a look at this ASAP.
 
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Old 11-09-13, 08:00 AM
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You probably have a problem (loose connection) in the panel, likely the main breaker itself or where it connects to the metal bars behind it.

Loose connections heat up and more so when more current is drawn through them.

It is possible that parts in the back of the panel have oveheated, warped, or deformed by now in which case it may be necessary to replace the main breaker and possibly the entire panel.

Usually these parts are riveted together and it is not unheard of for the parts to oxidize and no longer make good electrical contact, particularly if the basement is damp without a dehumidifier.
 
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Old 11-09-13, 08:01 AM
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Is it possible to replace only the main breaker on such an old unit, or should I just replace the entire panel, which I planned on doing eventually anyhow. Panel is a Gould 2040MB1200 (200 amp service).
It's possible you can do this as a temporary solution IF a replacement breaker can be found, but you still probably should replace the panel in the not too distant future. Gould became ITE which became Siemens. The fact that the main breaker is buzzing tells me the problem is at a connection at the main breaker, either a main lug, where the main breaker attaches to the bus or internal to the main breaker. If there is damage to the busbars, you need to replace the panel immediately. You probably have aluminum busbars, they cannot take much thermal abuse without having irreparable damage. In my opinion, this problem is not due to a loose neutral condition.

This project will require coordination with the power company to disconnect power at the meter and usually also requires a permit and inspection. I'd contact a local electrician immediately to have them look at it.
 
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Old 11-09-13, 08:47 AM
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I used to be an electrician and have installed and replaced panels. I'll take a closer look and see if the main breaker can be replaced. If not, I'll be replacing it. Sounds like it could be potentially dangerous.
 
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Old 11-09-13, 09:31 AM
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I am thinking that since the lights have been dimming, you probably have heat damage to the busbars, but an inspection is necessary, it could be just a bad main breaker. You also need to look at the main breaker and get the "Type". Google it and you should find quickly if it is obsolete, I am afraid it will be.
 
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Old 11-10-13, 12:10 PM
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Not buzzing today. Weird.
 
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Old 11-10-13, 12:36 PM
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Not buzzing today. Weird.
Electrical problems do not heal themselves, keep an eye on it.
 
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Old 11-30-13, 06:29 AM
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Buzzing went away the same day of my original post, but came back today. Sounds like the noise is coming from the 60A air handler breaker, and only when the auxiliary heating coils are on. Think I'll just go ahead and replace the 60A breaker.
 
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Old 11-30-13, 06:41 AM
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And check the bus bars for pitting or discoloration when you do.
 
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Old 11-30-13, 07:21 AM
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Bus bar and breaker contacts look nice and clean. However, one of the ears/tabs on the bus bar that connects to the suspect breaker is somewhat copper colored, whereas the other ear/tab is silver. Does this indicate heat damage due to arcing? I turned the breaker back on and no buzzing so far. Think it may depend on how long the air handler has been running. I'll check it again tonight when the temps drop and it is running for an extended amount of time.

Also, while inspecting things, I noticed that the cold water ground wire is just sitting inside the ground bar loose. There is no set screw. No clue where it went, and I imagine that it won't be easy to come by. It's a 30 year old Gould panel.
 
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Old 11-30-13, 07:50 AM
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Bus bar and breaker contacts look nice and clean. However, one of the ears/tabs on the bus bar that connects to the suspect breaker is somewhat copper colored, whereas the other ear/tab is silver.
The bus could be tin plated copper, but I didn't think Gould made copper bus loadcenters. That being said, they may have offered some with copper bus as an option back then. I'd replace the 60 amp breaker and watch it.

Also, while inspecting things, I noticed that the cold water ground wire is just sitting inside the ground bar loose. There is no set screw. No clue where it went, and I imagine that it won't be easy to come by. It's a 30 year old Gould panel.
The ground wire is probably a #4 copper. I don't know if you would have any other holes in the neutral bar that will accept a #4. If so, use one of them. There are also forked adapters available that will bolt to two smaller terminals on the neutral bus that will accept a larger wire.

Siemens Collar Strap for Siemens Ground Bars-ECCS1 at The Home Depot
 
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Old 11-30-13, 09:40 AM
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The cold water ground is aluminum wire. Not sure of the gauge. Regardless, I was able to find a screw at HD. Bought a $5 ground bar kit that came with one
 
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Old 11-30-13, 04:38 PM
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The cold water ground is aluminum wire. Not sure of the gauge.
Should be #2 if aluminum.
 
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