I think you might have had a low volts problem with the park power. If the volts drop the amps a load requires will increase for the amount of work, or watts. Watts = Volts * Amps AKA Ohms Law. 3360 watts with 120 volts will draw 28 amps. Drop the volts to 110 and the amps will raise to 30. Probably a problem with the camp site power point such as a loose terminal. Hard to fix when the camp ground is busy since they will probably have to shut power off to multiple sites to effect repairs.