I replaced my water heater elements and thermostats about a week ago. Everything was fine and dandy for about a week. Then this afternoon I noticed no hot water so I took a look at the insides and it looked like the wires caught on fire. Two questions: 1. What could cause this? It worked fine and then bam no more. 2. Would I be able to just replace the thermostat and it work again? It looks like the black wire is kinda burnt. Is it safe to replace myself or should I call in a plumber?