I have a confusing situation. I installed a bunch of lights, maxing out a cast 1200 Master series transformer and I am tripping breakers at a gfci outlet and one in the house. No breakers on the transformer are popping but the house breaker worries me. I checked the amps and am under the limit on each common and at 9 amps on the primary. Aside from the fact that I am pushing this thing close to its limit, is there any other obvious reason that might cause this?