i have a customer at a production plant near houston. one of the offices has a 5 ton condensing unit. someone saw what appeared to be a puff of smoke coming from the unit. the maintenance man checked it out and found a start capacitor with the bottom blown out. he told me he picked up a run capacitor and a start kit and replaced them, but wanted to wait for me to start it up so i could check it out. when i got there, i began checking components and noticed there was no run capacitor and a 3 pole contactor. yes, you guessed it. the nameplate comfirmed it is a 3 ph, 480 v unit. here's the kicker. the guy told me the start kit was installed 2 years ago by another hvac service company because a breaker tripped! (the run capacitor referred to was a 5 mfd fan cap) i checked incoming voltage and found no power present. checked for shorts to ground, and sure enough, the compressor was shorted to ground and the breaker inside was tripped. evidently the start relay and capacitor blew up when the short occurred. i thought i had seen it all, but this was a new one on me. apparently the start capacitor and start relay had no effect on the system during that two years. but then again, maybe it did and it just now gave up the ghost.