I addressed this question, briefly, in my FAQ section of our website but wanted to take it this week and go a little more in depth.
You discover your house is hot, and like most people, you go to your breaker panel. Let me tell you this: Sometimes the breaker doesn’t even look tripped and it will be, or sometimes you don’t know which breaker goes to your air conditioner because they are not marked. Let’s address the first “sometimes”. The breaker doesn’t look tripped. It doesn’t hurt to try it anyway and sometimes it will be tripped just a little. A good rule of thumb for checking a breaker is checking the temperature of the breaker BEFORE you reset it. Touch it lightly with the back of your finger, if it is hot call for service immediately. If not, proceed with resetting the breaker. The best thing to do is turn it off: push it HARD all the way to the off position and then wait a second or two and push it HARD to the on position. Now for the second “sometimes”: You’re not sure which breaker goes to your air conditioner because they are not marked. Look down the line of breakers and try to find the one that is just slightly, or all the way switched to the off position and try that one, if you don’t have any luck then you’ll need to call your air conditioner repair person.
Keep this in mind: Your breaker is tripped for a REASON. Your breaker is there to protect your home, your equipment and your wiring, so don’t just keep resetting it, ignoring the problem. If the wires get too hot you could cause a fire, and that wouldn’t be good! It’s sometimes possible that the trip is due to a power surge, thunderstorm or weak breaker but it’s not worth taking chances.
I do not recommend tightening the wires yourself if you suspect a loose connection, this is high voltage and can be very dangerous.
Another common problem that could be causing your breaker to trip is a direct electrical short in the wiring or the equipment. You’ll know this is the problem if you reset the breaker and it immediately trips again. DO NOT RESET IT AGAIN. Call for service immediately.
Sometimes the breaker will trip if the compressor is having a hard time starting due to it being completely stuck or just tight. If this is the case you can call for service and have a compressor hard start kit installed to remedy this situation. Or it could be an imploded or bad run capacitor on the compressor. Either way, it should be looked at by a qualified service technician.