[Jack Houpe]

Do what Dean recommends and also check the plug and the pedestal for poor connections or hot spots. I would check voltage at the breaker and if it's low when the AC is on start working your way back the the pedestal. IR temp gun is a good item to carry you can spot hot breakers and hot spots without exposing live wires. Make sure the breaker has a good connection at the bus bar in the panel, I've seen breaker contacts overheat from poor connection and cause this same issue you have. If you are uncomfortable with electricity then find someone who is knowledgeable.