1994 29.5 After plugging into dockside power I noticed the reverse polarity light on. Not familiar with this situation I turned on the hot water heater breaker. Smoke started coming out from the breaker panel. WHAT A SCARE FOR MY WIFE AND I. Luckily no fire just frayed nerves. After removing the panel I found a chard part (unidentifiable. Diode, resistor, fusible link?) that went across two poles on the 30A main disconnect breaker. Can anyone tell me what happened, what the part is that fried and its function? Thanks, Smokey Joe