low voltage lighting

I have a "Twilight" low voltage lighting sytem, 500W.

More than 50% of the time when the timer ( light sensor ) turns on the system, the breaker in my main panel trips. I already have the sytem on it's own dedicated 15 amp breaker. This is the second transformer I have tried. The original one gave me the smare problem, so I exchanged it at the place of purchase. The connections in the transformer are soldered on to the lugs and secured tightly. I am definetly under in accumilitive wattage. Cable size is 12 guage on to runs, 14 on one run. The odd thing is, with no load, all cables disconnected, the transformer trips the panel breaker the same precentage of time !! Am I possible "underdriving" the system ?

Thanks,

Tim

 

The transformer's turn-on surge could be too much for a weakened breaker. Have you tried swapping out the breaker?