[encantotom]

a little lesson in circuit breakers. russ, correct me if i get it a little wrong.

i used a square D trip curve and looked at a 20a breaker. a trip curve tells you for a specific size breaker how long it takes to trip at different currents.

a motor has a startup current that can be as high as 3x the running current for that motor. so if it is a motor that runs at 8 amps (just a number i picked), then at startup it can be 20-25 amps. but that is only for 1 second or less.

a 20a square D breaker is rated to run for 13 seconds at 25 amps.

if you started at 13amps like you said, and climbed 1 amp per second, i did some averaging. it would take 7 seconds to get to 20a. the rating of the breaker (no calculus needed to do that, ha). then at 25 amps (5 more seconds) the trip curve says 150 seconds to trip. at 31amps which is another 6 seconds (for a total time of 18 seconds) the trip curve shows it can run at that amperage for 65 seconds.

so some kinda awful averaging says that it could run for over a minute at that amperage without tripping the breaker.

btw, it can handle 100amps for 2.5 seconds (a 20a breaker)

i dont know what brand breakers you have but the trip curves for residential breakers should be similar.

russ, am i close?

tom