On/Off Operation Times of Breakers

Whatever it says in the original equipment manufacturer's Operation and Maintenance Manual.

RTFM.

i think breakers are temerature sensitive. a "short" will kick it in milliseconds where as an appliance drawing a maximin load may take some time to kick it. possible dure to voltage flucuations from the grid.

As stated before, shorts, which create an over current situation are measured in milliseconds, usually instantaneous disruption. And breakers also are designed as a thermal sensitive disruption release in the case excessive heating from large load demands over the rating.

But what is the question really implying?

Are you asking how many times a breaker can be turned on and off before the latching is worn?

How many times can the breaker with stand over current disruption before it suffers a meltdown and is no longer reliable?

Your circuit should only be designed to use up-to and not more then 80% of the rating of the breaker itself. This helps to insure the longevity of the breaker. And if it is being used as a lighting circuit for a building with many fixtures, you should design a lighting contactor to eliminate the constant on/off cycling of the breaker anyways. This in itself will solve any breaker issues in terms of short life span.

Maximo

what is a lighning contacter? i'm having the same problem.

I assume that you want to know the typical "closing time" and "opening time" of circuit breakers. If so, today's modern circuit breakers' closing time is between 40 milli seconds to 60 milli seconds and typical opening times range from 10 milli seconds to 40 milliseconds. For accurate values, refer to the breaker catalogues.