As it is starting to warm up we started to run our A/C and noticed it wasn't cooling the house. The fan was blowing so I went down and checked the breaker and sure enough the two 30amp breakers for the A/C were tripped. I flipped it and it held for a second and tripped again. Multiple attempts resulted in the same outcome, it would trip within seconds. I went outside and pulled the disconnect switch, went back and flipped the breaker, and it held. So I go back outside and reinstall the disconnect switch. I hear a slight humming sound and then a little click. After returning to the basement I see that the breaker has tripped again.
One thing of interest is that all this happened with the A/C turned OFF at the thermostat. If the thermostat was set to A/C the breaker trips even faster and even sparks.
I am a first year electrical engineer student who was recently laid off from work. So needless to say I would really like to try to diagonse this issue myself for financial and knowledge reasons. Thanks in advance for any assistance guys