I'm installing a new electric water after the heater coil on my boiler failed so everything is new. I can't figure out what I did wrong but I got a delayed (2 min. or so) snap, crackle from the wires after energizing the circuit. The WH is a 50 gallon Rheem unit with a black wire and red wire coming out of the casing and a pinch ground screw on the cover plate. From the fuse box I installed 10/2 wire to a double pole, single throw breaker. Black to one pole, white to the other pole, and bare to the ground busbar. I connected the black wire from supply to the black wire in the WH and the white wire from supply to the red wire in the WH, the bare wire went into a slot and was held in place by the green ground screw. When I flipped the breaker the display on the WH lit up and I was able to switch the WH on. After 30 seconds or so I noticed a smell and assumed it was the new element heating up, then after another minute or so I heard a popping noise and saw sparking from the top of the WH. I flipped the breaker as quick as I could. Now it looks like the burn smell was the plastic wire nut melting, but everything else looks okay. Can somebody please tell me what I did wrong?

Question?? can you put 4 track lights with 4 50 watt halogens on 1 dimmer switch? my issue is I bought a 600 watt dimmer switch installed it, and it works, but the aluminum plate around the switch gets pretty hot to the touch. It doesn't throw a breaker, the wires are not hot, just the aluminum plating. I then went and bought a 1000 watt dimmer switch, installed it and the same thing happened, it still got hot so I took 4 bulbs out of one track light to reduce the watage again but it still getting hot. Any ideas??