what size of wire should I use for my 1.5hp aircon, 220volt
You should use AWG 14 Copper wire.
It depends on the amperage draw, it should say on the rating plate. 14/3 for 15 amp, 12/3 for 20 amp, 10/3 for 30 amp, 8/3 for 40 amp and 6/3 for 50 amp and so on.
If the distance to the power source is 100 ft or less a #10 wire should work. If it is further than that you should call an electrician. added note: # 14 copper is for light service wire. It would max out under use with an AC and possibly overheat.
#12 because it runs for 3 hours or more and if you get a larger one it will be cababile of running it
