A/C circuit breaker keeps tripping.


Old 07-07-02, 10:45 PM
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Unhappy A/C circuit breaker keeps tripping.

I left my house this morning and the A\C was working fine. Came home several hours later to hot house. Inside fan unit continues to run and blow hot air. Outside unit not running. First checked contactor for any bugs or debris. None. Then checked circuit breaker box. Low and behold, the A/C breaker had tripped off. I reset breaker and thought my problem was solved. Nope, it wasn't. The circuit continued to trip after staying on approximately 20 plus minutes. Reset the breaker twice with same results. Now the breaker itself will not stay in the on position. I'm hoping that maybe the breaker fuse is bad once that happen. I been in my home over eight years and this has never happen before, but the unit is about 15 years old. Please send Kooool advice soonest.




Last edited by msphatt; 07-08-02 at 10:24 PM.
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Old 07-10-02, 12:53 AM
lynn comstock
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Replace the breaker (Stay at the same size.)

Breakers trip from HEAT. If the breaker has a loose connection at the wire out terminal or at the buss bar in the back, the loose connection will produce heat and trip a breaker. If the panel is in the sun, the sun load adds to the heat inside of the breaker. Low voltage adds to the heat also. These types of trips tend to happen in the heat of the day.

If house was warm tells me that it was not a thermostat-recycling problem. The compressor is almost sure NOT to be the problem whenever it takes 20 minutes or so to heat up the breaker for the first trip. Then when the breaker is already hot, the next trip happens in a much shorter time span. When you see this pattern REPLACE the breaker. They don't last forever.
Old 07-10-02, 08:39 AM
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The advice given so far is correct and as stated breakers do not last forever. It was mentioned about the buss that the breaker sits on possibly being burned or it is possible that through the years the connection from the breaker itself to the bussbar has deteriorated. Make sure the breaker is in the off position and pull it out and make a visual inspection of the bussbar that it sits on and the bussbar connections in the back of the breaker. At the same time tighten all of the wire terminations between that breaker and the condensing unit, many times this kind of tripping is due to a termination becoming loose due to constant heating and cooling.

If you notice during your visual inspection that the bussbar in the breaker panel appears burned or damaged that panel or it's interior will need to be changed out! This should only be done by an electrician!! If the bussbar is burned or damaged and you install a new breaker and the tripping stops don't be fooled that all is well. The bad connection to the bussbar will cause damage to the new breaker and it too will fail. If there are problems with the bussbar you need to replace expiditiuosly, these types of problems are one of the most common causes of fires that are electrical in nature.

You mentioned that he a/c unit is 15 yrs. old. As an a/c unit gets older the compressor tends to draw more current. This is usually evidenced by the condensing unit coming on and the compressor trying to start and drawing an excess of current ( compressors typically draw six times their running current when they start) this will cause the breaker to trip. You can usually tell if this is happening when you see your lights in the house dim when the a/c comes on. However, this can also be caused by loose connection. The only sure way to tell what is happening is to put an amprobe on the circuit and measure the amperage being drawn by the unit.

It was also mentioned that breakers sense heat and that ambient temperature could be a factor here as well. I would say that the ambient temperature would not be a factor in this situation. If that breaker has operated in the same space for the last 15 yrs. there would have to be something new around the breaker causing more heat than it has previously operated with.

Bottom line tighten all of your connections, remove the breaker and inspect the bussbar and the connections on the breaker, if they all look relatively clean and show no evidence of burn, put everything back and try operating the unit again. If the unit fails to keep running then replace the breaker. You will know if it the a/c unit when you install the new breaker this way. If it is the unit then the new breaker will not solve the problem, that breaker would trip too. DO NOT INSTALL A LARGER BREAKER!!!! The nameplate on the condensing unit should specify what the largest breaker size is that can be placed on that circuit.

Good Luck
Old 07-10-02, 08:45 AM
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I forgot to add this to my earlier post!!!

Breakers do trip from heat as mentioned, they will also trip from short circuit current. Normal breakers are what are called inverse time circuit breakers. That is to say, the time that it takes to trip is inversely proportional to the amount of current flowing. The more over current being drawn, the faster the breaker will trip.

I came back and added this to illustrate the fact that it could be the a/c unit that is on it's way out and you are just now beginning to see the effects. This can be the first sign of that kind of trouble. Whenever we install a new breaker anywhere, we turn the circuit on and let it run for about twenty minutes to make sure that it wont trip. Twenty minutes is about the time that a breaker will take to trip with a minimal overcurrent condition.
Old 07-10-02, 03:00 PM
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I had the same problem a month ago

I had the same problem a month ago. My AC Unit was barely blowing out warm air and the circuit kept tripping. I called a Heating and Air Condition Repair shop. After paying them $70 (a great value) it was determined that the circuit breaker was bad and that I needed freon. The tech popped the circuit breaker out and told me to go to a store Like Home Depot and buy a new one. The circuit breaker itself ended up being around $6 and I have not had that problem since.
Old 07-12-02, 12:26 AM
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Talking A/C breaker tripping

Thanks to all for the good and correct info. The breaker was bad. It took a miracle the type I needed. I still have the old pushmatic double pole type. Only one store in the whole city of New Orleans carried it. The old Mom & Pop Hardware. Cost of $42. It was worth it.

Thanks all,

Kooool Again.

P.S. This is a wonderful service to use do-it-yourselfers. I will pass this site on to all my buddies

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