Subpanel popping CB in main panel
Have a (hopefully small) problem and would like some input.
The small building behind our house has a subpanel which is tied into a 30 amp breaker in the main CB box in our house.
This subpanel has:
1 – 30 amp double breaker for the dryer
1 – 30 amp double breaker for the hot water heater
1 – 30 amp single breaker for the lights and outlets
When the dryer and hot water heater are on at the same time, and everything else is off, the CB in the main box trips.
Shouldn’t the CB in the main box be more then 30 amps? Any help or advice would be appreciated.
30 amp single breaker for lighting is too large, ’cause I bet you only have 12-2 wiring. It needs to be a 20 amp breaker, or 15, if you have 14-2 wiring.
As far as the tripping, it is simple math. You have the entire subpanel on a 30 amp breaker. You attempt to run a 30 amp water heater and 30 amp dryer at one time, it will overpower the 30 amp breaker in the main box. Now, in order to increase the size of the breaker in the main box (which is too small), you have to run larger wire to the outbuilding to handle the increased amperage draw. What size wire is being used to feed this subpanely?
