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Discussion Starter #1
I've got a weird electrical situation at my home that I'm concerned about. I've already got a call in to discuss it with an electrician, but I'd like to be better informed when I speak to him.
My power through two different circuits started failing yesterday in an intermittent pattern, but there didn't appear to be a tripped breaker on either circuit, and resetting the breakers didn't help at all.
Oddly, what did help was resetting the AC system at the thermostat, though I'm pretty sure the AC is on a completely seperate circuit. Even more odd was that while the fan runs constantly, the AC doesn't seem to be cooling the air. If I shut the AC off, one or both of the other electrical circuits fail again. More confusing still is that the breaker switches for the failing circuits appear to be on the other side of the electrical panel from the AC breaker... if I have them identified correctly. The circuits weren't labeled when I bought the house 20 years ago, and I've never thoroughly tested and labeled all of the individual circuit breakers. Is it possible that the AC fan, and the AC compressor are on seperate circuits?
I'm guessing that the problem is in the electrical panel itself, but I'm not knowledgeable enough to know where, or how to confirm this. Any help anyone could offer would be much appreciated.
 

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The AC is likely 240 volt device.
It sounds like there could be an issue one of your hot legs. The voltage is back feeding from the good leg to the bad leg through the AC.
 

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You can call the electric company and ask them to come out and "retorque your main lugs" (main electrical connections). They usually do this for free. Explain the problem you are having just as you did above.

These can work themselves loose, especially if they were not installed properly to begin with. If aluminum wire, they need anti-oxidation goop applied at the connection. And then the connections need to be tightened with an inch pound torque wrench to the panel/meter manufacturer's specifications in inch pounds.

If a high amperage connection is not tight enough, it can heat up/cool down, heat up/cool down... and work itself loose. And aluminum wire can oxidize and cause a poor connection to the extent it will not work any longer!

Note these connections ALWAYS HAVE LIVE ELECTRICITY EVEN WITH THE MAIN BREAKER OFF! So don't try to tighten any connections yourself.
 

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So, you think the electrical company will send someone for free to pull the cover of the electrical panel and check things out? That would be fantastic, even if they weren't able to fix it, but could tell me what was wrong.
 

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So, you think the electrical company will send someone for free to pull the cover of the electrical panel and check things out? That would be fantastic, even if they weren't able to fix it, but could tell me what was wrong.
They will not pull the panel cover, but will only look at their stuff to the meter.
 

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Discussion Starter #6
I called the power company. They're sending someone out to check up to the main connection, but that's on outside at the meter box. Wouldn't a problem there effect the entire house, rather a specific circuit?
 

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I called the power company. They're sending someone out to check up to the main connection, but that's on outside at the meter box. Wouldn't a problem there effect the entire house, rather a specific circuit?
No. Let them check their part. Good chance its their problem.
One loose wire on their side could cause your symptoms.
You might should turn off your main breaker until this is resolved.
 

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Discussion Starter #8
The power company guy just left. He said that he was able to get a quarter turn on the main lug, but everything else looked good on his side. I pulled the cover off the electrical breaker box, and tightened up my main connections while the power to the house was off. There wasn't much give there. I didn't see any other obvious loose connections or heat/corrosion damage. When power was restored, the symptoms are unchanged. At this point, I'm thinking that I might have been mistaken, and that multiple circuits might NOT be involved other than the circuit with the 120 inside blower fan and the 240 external AC unit.
I'm beginning to think the main problem might be related to the AC somehow. Even though the thermostat says that the AC should be working, and the blower fan is running on the "auto" setting, there is no noticeable cooling going on. If the AC compressor is locked up, would that cause possible failure in the inside blower fan circuit?
 

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It seems at least you have somewhere to start. The AC. Is it a split system? Condenser and compressor outside with evaporator and blower inside? Ductwork? No ductwork?
If its not cooling, that would seem to be a reasonable place to start. Agree?

I'm not feeling your question. Not really understanding it.
If the symptoms are AC related, why not start with the AC.
 

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Discussion Starter #10
My concern about the electrical system is because of the strange circuit behavior that's related to the AC issue. I lose a 120 circuit inside when I turn off what I think is the 240 breaker to the outside AC. The inside blower fan keeps running, but I lose the 120 feed to part of my kitchen and family room. I lose the same 120 circuit PLUS the inside blower fan when I trip a different breaker on the panel. In fact, if I simply turn off the AC on the thermostat, I lose the same 120 circuit WITHOUT any breakers tripping on the panel.
 

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Discussion Starter #11
I suppose I should confirm my belief as to the 240 breaker. It's a larger blue "paired" breaker labeled "50", and has a pair of larger black/white wires coming out labeled "Type TW", and "600 V Oil Resistant".
 

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Discussion Starter #12
And yes, it's a split system with the blower fan and ventilation ducts attached to the furnace, with the compressor/AC fan outside.
 
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