Nov
06
What Is The Appropriate Circuit Breaker Amperage For A One Horsepower Aircon?
ByThe one hp aircon will be plugged to a 230V/60Hz power source. According to the vendor’s display tag, the Energy Efficiency Rating or the EER (1 to 12 of which 12 is the most efficient) is 10.5.
2 Comments
November 6th, 2009 at 12:01 pm
A1 Hp air con is 746 watts. Assuming its power factor is 0.8
I= 746/230(0.8)
I =4.05 amperes.
Air Circuit Breaker rating = 2.5(4.05)
=10 amperes.
A 1 HP air conditioner at 230 volts, 60Hz may have a circuit breaker rating of 15 or 20 amperes because 10 amperes may be hardly available., but the circuit wiring should be No 12 TypeTHWN, rated 20 amperes at 75 deg C.
November 6th, 2009 at 12:23 pm
One HP = 746 watts. The EER is an indication of the seasonal efficiency of the unit-not the motor alone, so assume that the motor efficency is about 0.92 and the power factor is around (for a capacitor -run single phase motor) 0,85. Actually, the full-load current for the motor should be on the nameplate, but this is an estimate: F.L current =746 w./230 v./0.92/0.85=4.1 amps. Code assumes the breaker value will be 2.5 times the FL current, so the breaker should be about 10 amps. The lowest rated CB readily available is 15 amps, so use that breaker and wire the unit with #14 wire rated 15 amps at 600 volts. Note that a circuit breaker should not be continuously loaded at more than 80% of its rating, so .8x 15 = 12 amps, which is greater than your FL current so the 15 amp CB is ok.