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.

Doesn't really matter what size motor it is, unless it has a soft start or VFD it's going to have a huge inrush current as a proportion of the running current. Here's a quote from Cooper (manufacturer of fuses and circuit breakers):

When an AC motor is energized, a high inrush current occurs. Typically, during the initial half cycle, the inrush current is often higher than 20 times the normal full load current. After the first half-cycle the motor begins to rotate and the starting current subsides to 4 to 8 times the normal current for several seconds. As a motor reaches running speed, the current subsides to its normal
running level.

So if the AC draws 10 A, 50-60 amps would be quite normal to see on turn on. Breakers can usually handle this inrush, and breakers can also have different trip curves, allowing more or less inrush than others. This is similar to a time delay fuse. A regular and time delay fuse of the same current allow the same long term current, but the time delay gives more time for motor inrush and similar. I remember as a kid the circuit with my dad's table saw needed a time delay fuse, as a regular fuse would blow the instant you switched the saw on.

It's really cool to put a scope on the AC lines and watch the actual inrush current and voltages. I've done that at work for several different devices. It's staggering how high the peak currents can be for the first full half cycle.

EDIT: Missed there was a second page of comments before posting, so this was already covered. Oops.