WE WERE SITTING IN OUR TRAVEL TRAILER WHEN I SMELLED SOMETHING BURNING, LIKE AN ELECTRICAL BURN. I WENT AROUND OUR TRAVEL TRAILER AND LOOKED UNDER THE SINK AND SAW THE WATER HEATER SMOKING. I IMMEDIATELY TURNED OFF THE ELECTRICITY. IT TURNS OUT, THE AC JUNCTION BOX THAT ATTACHED TO THE WATER HEATER HAD CAUGHT FIRE DUE TO THE WIRE NUT NOT BEING PROPERLY SECURED TO THE WIRE. TRAVEL TRAILER WAS STATIONARY.