However, a main shutoff circuit breaker is not ... In a 100 amp sub-panel, how many 20 amp breakers are there? A 100 amp sub-panel generally will have enough room for 12 to 20 circuit breakers ...

A 200-amp breaker is appropriate for a home upwards of 2000 square feet. Smaller buildings can use 150-amp or 100-amp; small homes and subpanels can use as little as 50-amp. Uses the entire 240 ...