Originally Posted by deniseO30
There was a time when a 36,000 btu central air unit would draw nearly all of the 40 amps at 230 volts it was hooked up for. Now.. they run on about 9 -12 amps for the same capacity.. while they have made great strides in HP vs capacity. They still need a good share of HP to handle any kind of capacity.
This is getting a bit off topic. The current draw of any refrigeration circuit is dependent on the cooling load. The factors that determine the load include the temperature and humidity both in the area being cooled and the outside air, where the heat is being rejected. A typical 3 ton condenser (the exterior component on a typical central A/C) has a 30 amp MAXIMUM overcurrent protection requirement. Yours may be on a 40 amp breaker, but shouldn't be, and if you look in the disconnect you'll probably find 30 amp fuses. My house's 3 ton (36,000 btu/hr) condenser runs about 18-20 amps fully loaded (measured last week, with outdoor temp >100 F) , and it's 19 years old.