I think mine is a 1000 watt in my 7.3, but YES DO USE A HEAVY CORD!!!! I learned the hard way! You might not loose your truck, but you might loose the house.
Few yr ago I had mine plugged on a timer, plugged in the garage, 100' 16 ga cord out to the truck, about -25*. For some reason went into the garage before going outside.....garage full of smoke, black soot all up the wall & sheetrock, plugin smoking, etc, etc. Breaker didn't trip!!!!
I figure house been on fire in another 30 min if I hadn't found it!!! Small cords can't carry the amps, can carry the volts but not the amps!
Sooo, I got rid of all my cords smaller than a 12 ga. For that matter now nothing on my property smaller than a 12 ga to use on anything! Saws, drills, TRUCKS.....