The main line outside is on a 100 amp breaker, the main in the home is also a 100 amp. and the W/H breaker is 30 amp. after re-placing all the breakers it still did it. Replaced both thermostats and still tripped the main. Disconected the bottom element and the W/H was fine, I called Bradford White and explained everything that had happened and they said the bottom element could be the problem even though its a new W/H and the are making good on it. Oh by the way, the line comming from the curcit box to the W/H is a #10 gauge wire and it never got warm at all during the problem with this. What was happening is the top element comes on first and after awhile 15 minutes or so the bottom element would come on and this is when all hell broke lose. it was a dead short do to the faulty bottom element. this is what the company said. I HOPE!! going to replace it saturday, she running on one element right now.