Thor Forums

[Chance]

Originally Posted by gnach

Coming back to my suggestion of keeping the 30a in place... the 15kw A/C specs call out Running Watts Desert: 2025 and Locked Rotor Amps: 61. 2025 watts / 115vac = 17.6 amps. Sizing the breaker at 125% (Natl Code) would be 22 amps. Since a 25 amp breaker isn't available the 30 amp would be my choice for the extreme load. Yes, not perfect, but not going to overheat the breaker either. -2cents worth

Current rating for desert conditions are even higher than your estimate because they are based on lower voltage and also include a power factor correction.

Having said that, Tfryman and Porkchop are absolutely correct. A/C breaker should remain at 20 Amps not only to protect the wiring from the panel to the A/C, but also to protect the A/C itself. Even if the wires don't start a fire, I'm not sure I'd want my A/C running at higher currents for long periods. Even a 25 Amp breaker could lead to A/C early failure. I'm aware they have other built-in protection, but I wouldn't oversized the breaker at all.

It's too late in this case, but a future solution is to install higher efficiency A/Cs that draw significantly less power. I'm not sure if Coleman has a 15,000 BTU/hr Power Saver A/C, but their 13,500 only pulls just above 10 Amps under standard conditions.