how to connect cables to switches 240 box
Your only hope is that someone wired the box not to code and that there are two wires going into the offending breaker. If you can't separate wires you can't distribute the load.
It is inserting a breaker into a service panel.
You use the correct size breaker depending on the size wire in the circuit. If the circuit is wired with AWG #12 wire use a 20 amp breaker. If it is wired with AWG #14 wire then use a 15 amp breaker.
For a circuit breaker to protect anything, it must be wired in series with whatever it is protecting.
A GFCI receptacle can pass it's "protection" to other outlets wired from it. If the GFCI trips, all outlets wired from it will "trip" also. A GFCI tripping will not necessarily trip the circuit breaker in the service panel.
Example sentence - We hired an electrician to at the circuit breaker and install an updated panel.
which circuit breaker? either engine compartment or r.h. dashboard panel
If you are talking about a breaker in a house panel then a 15 amp breaker would be used. It is the smallest amperage breaker that you will find in a house panel.
Main circuit circuit breaker
A dedicated 20 Amp circuit wired with 12/2 wiring an a 20 amp breaker.
A 15 amp dedicated circuit breaker should be used for the dishwasher. The disposal can be wired to the general kitchen 15 amp circuit.
The breaker panel.