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My house was built in the late 60/early 70s - 3 bed 2 bath. We have a weird situation where our house is partially losing power. If the AC is on, power is great no issues, once the AC reaches the temp we set it at, ac will power down (go idle), which is normal.

Weird issue is that randomly, minutes later or even hours later (if the ac is not triggered on manually or automatically), the power to like 80-90 percent of the house dies. The only power that stays on is the hallway power (thermostat is located in hallway), one bedroom power, and guest restroom power...other than that - all power is out (inside, outside, garage, kitchen, etc.).

We check the breakers and all breakers look good and nothing seems to be popped or out of the ordinary.

The weird thing is the only way to get the rest of the power back on is if we get the ac going by turning the temp down, just so it can trigger on.

Any ideas on this? Any help or guidance would be appreciated. Not sure how to go about troubleshooting this issue.

isherwood
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Deepak Gautam
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5 Answers5

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I'm going to slightly disagree with the other answers and guess you have an open hot conductor. Either way, the answer is the same: call the power company and report a power outage. The problem is very likely at the pole, so they'll come out and fix it for free.

For more information on why losing one of your hot conductors will cause the symptoms you're seeing here, take a look at Harper's answer to a similar question.

isherwood
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Nate S.
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You have an open or lose neutral or high leg and that it dangerous. Call your power company and report an outage... right now. They will respond quickly. These problems are usually their problem and they will fix it for free. In the event that it's your problem, they might still help you out and fix it if they can.

JACK
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A similar issue just happened to me. Air conditioner was on, but not blowing cold air. When I turned it off at the thermostat most of the house power went off too. I read this blog and realized I should call the electrical company. They told me that since it was the AC it’s probably an internal problem and have Electrician or HVAC look at it. I called an electrician and they charge $150 just to come out. Instead of paying that, I called the electrical company back and said, the electrician says it was an “ external intermittent power with a neutral issue.” They came out and found that the wires going to my house had rubbed so badly that there was a short. He actually showed me where it had burned through the steel support wire. Definitely a safety issue! Two hours it was fixed for free and my air conditioning blowing cold air right now.

Kaa
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Posted by question author:

What [the energy company] said when they came out is that everything is getting power properly, but when he pulled the breaker for the AC out it was all melted and bud bars had some burning on it.

Seems it’s a common issue with Zinsco breakers.

isherwood
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This may be a problem with the neutral. The a/c condensing unit does not use the neutral so it will work fine, but the air handler inside does use the neutral.

Depending on where an intermittent or loose connection is in the neutral wiring there could be damaging high voltage on some 120 V circuits and low voltage on other 120 V circuits. At the point of a loose connection you would have damaging and dangerous local heating.

Have you had any lights blow or equipment fail after these outages?

A problem with the neutral is an emergency requiring immediate intervention, very likely professional, unless you are experienced. If the problem is at the pole or between the pole and your meter, then the power company will fix it. But if the problem is in your house wiring you need a professional repair immediately.

Edit Does your house have aluminum wiring? If so, you may have loose connections at the neutral bar in the panel.

What is the brand of your panel?

You can open the door of the panel, but I don't advise you to remove the "dead front" unless you are experienced or can otherwise do it safely. There is real risk of injury or damage with the dead front off.

Jim Stewart
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