I have an 240v outlet in my garage that was wired to use with a kiln. It was never used for this, and now I want to use it to connect a window AC instead. It current has a 60-amp breaker. I assume it's a bad idea to run the AC on this, since it's much too big. Can I just replace it with a 20-amp breaker? I assume it needs a two-pole breaker since it's 240v, right?
The outlet was never finished, and it has 4 wires. Black, white, red and ground. I want to install a 6-15R receptacle. I will connect the hot black and hot red and ground, and leave the white capped and unconnected, correct?
Finally -- is it always unsafe to use an extension cord with the AC? My preferred AC model comes with a cord that is too short. If I use an appropriate extension cord (3ft, 20A, 5000W), would that really be a problem? I will probably just get a different AC model with longer cord just to be safe, but is the extension really that bad if it is dimensioned correctly?