10-gauge vs 12-gauge extension cord: 10-gauge is the right choice for a 50-foot RV run

12-gauge is technically fine for short bursts at 15 amps, but at 50 feet the voltage drop makes your RV air conditioner’s compressor work harder, run hotter, and risk melting a plug or tripping a breaker. 10-gauge keeps voltage drop under 3%, handles startup surges, and lets you run other devices on the same cord without issues.