Artum Snowbird wrote:
It could possibly be loose wiring. When you are heating, the wiring if it's loose would create a high resistance point.
Definitely check the positive and negative in your 120 volt panel, and tighten anything that appears loose.
If it has only occurred at this one shore power location and not at any others, that might tell you something to. If everyone is pulling heat in the middle of the night, their lines might be stretched to put out sufficient for everyone, or their plug or your cord might have loose wires too.
If you can put a meter on voltage when it's running to see if it stays up, or if it gets voltage drop from overuse, that would help too.
The only problem with that theory is that the heater runs strictly on 12v.