A JOKE
Connect 120vac to the black wire and whatever smokes and catches fire is the culprit.
One Fruitwood Blunder, I had to re-wire for Good Sam had snarls of wire added on. I had to call the adjuster out and he took Polaroid images and told me to wait. They and the owner smoked the peace pipe and I was finally given the go ahead to fix it. "Someone" over rode (bridged) the neutral separation between shore power and generator and when the trace inverter was connected, and the rig was connected to reverse L1 and L0, all hell broke loose. I must have used thirty terminal blocks in the fix. I had informed Good Sam that wire nuts would be used "Over My Cold Lifeless Body" Not a hint of resistance from Good Sam. I rewire with 12-gauge receptacles wire. Red and yellow for interior lights and 12 volt battery feed. Black for 12-volt negative is for corpses waiting to happen. Black and white for L1 ID and Black with white tracer for L2.