Call whirlpool and inform them. Looks like it started somewhere around the infinite switches they are known for going bad but you don't see too many fires as a result of it usually it's the element doesn't work. Anythings possible could of been a lack of air circulation, poor wiring, previous repairs done wrong, wiring in your wall causing a spike that went past your breaker or oversized breaker. Replace the unit that's a low end model they have them new around 4-500.