What happens if you start an electric hot water heater when the tank’s not full? This.

Hopefully my dumb mistake helps you out the next time you’re performing maintenance on your electric hot water heater. In my case, I was draining and flushing my tank, which is a routine maintenance task. But I flipped the breaker on before the tank was completely filled, and because the upper element was not yet underwater it was almost instantly destroyed. Amazing what 220V can do. Stay safe out there!