Is this normal for a 30 amp breaker

LoudRam wrote:
We're talking about TT AC units not household or commercial units. My trailer AC unit is on a 15 amp breaker. If that has a 50 to 60 amp draw at start up, there is something wrong.

Nope. In fact, 50-60 Amps is probably uber conservative for initial in-rush current, and most ammeters cannot measure the instant current spike when the switch is closed. Keep in mind when the compressor is started, it is in a stalled rotor situation. If you think about it, the stator at this point can be considered just a really long wire, and at the moment of power-up, looks exactly like a dead short circuit. Once the rotor starts spinning, it creates what is called back EMF that fights the incoming current flow. Eventually, as the rotor gets up to speed, it creates a back EMF that equals the incoming voltage. This is why when you start your A/C unit, your room lights flicker hard. That compressor is a REAL BIG sponge for a second.

Now, as to why your unit can use a 15 Amp breaker without tripping it on startup? Well, other than a soft start kit, most breakers, as mentioned before, use bi-metallic strips that warm up with current flow. The more current, the hotter the strip gets, until the current flow exceeds the rating, hence heat in the strip, the strip flicks, and opens the breaker. However, the strip takes time to heat up, and the initial in-rush current of a starting A/C unit isn't present long enough to heat the strip to trip point. Usually. There are exceptions (like warm to hot ambient temperatures, worn strips, etc).

Cheers!
Mike