Why are people leaving these fireplaces running at night while asleep? I sure don't trust mine enough to do it. There are other solutions.
My fireplace, original to my 2007 build Bighorn, has an internal construction of the heating element akin to a double insulated electrical device. The heating element (which I have never had trouble with, and never had to replace) is inside its own heavy screened metal enclosure box, and that is mounted within the metal enclosure of the fireplace controls sheet metal surround. While I live fulltime in the Bighorn in Southern California, long ago I decided to use the site provided electricity for as much heat as I can, not needing to buy much propane that way. In winter time I run the fireplace nearly fulltime (though not at the full heat setting) and a small electric space heater as needed. I pretty much just use propane for my stovetop cooking, and recently did my first propane tank refill in about 2 years of fulltime living. I also have an electric induction cooktop portable burner to back up the propane stovetop, but don't use it much.
The biggest safety issue I encountered with this setup, was the RV industry's use of insulation displacement connector (think Scotchlok) for the wiring for the 110 VAC outlets throughout the trailer. I only discovered how flaky these connectors are by noticing that the pilot light on my space heater was flickering while using the heater. I investigated the situation, and then rewired ALL 110 volt outlets inside the trailer with standard wire and clamp screw home outlets mounted in boxes.
On edit: After reading most current postings on this thread, this definitely sounds like Insulation Displacement Connector high current connection failure. Too small a wire/connector contact area on the IDC connectors versus a standard outlet wire/compression screw to handle full rated 15 amp branch load.
Use the Search function on the forum for "Insulation Displacement Connectors"
You Tube on RV Insulation Displacement 110 volt outlets:
to learn more about this.