combine circuit breaker switch and fused together.
As for why you might want to use both fuses and circuit breakers together. the fuse has a much higher capacity to solve the fault current. if the prospective noise flow exceeds the breaker rating you have, the fuse that limits the upstream immediate current will protect it. a typical breaker has a rating of 10ka to 14ka compared to a typical rated fuse of up to 100ka.
How do you combine two things that have the same purpose? You put them in series but the question is why .. if you have a fast blow fuse in series with a circuit breaker, or a breaker having a higher current rating, then you probably do not have to rearrange the breaker.
If you place it in parallel then you need both the breaker for the trip and the fuse to blow before the circuit opens, and can be closed again by resetting / replacing both so there is not much gain there except for the very special case of remote monitoring.either suppose the circuit breaker is a type of thermal strip or bi metal. which will take some time to operate which in short circuits may take too long to protect the cable. it will be set to operate on a continuous overload possible in 5 seconds.
The fuse on the other hand will be judged far above the excess rating of the circuit breaker but will operate almost instantaneously in short circuit situations.You may use this setting in the motor start circuit where there is a momentary jump current of 6 to 8 times the normal running current of the motor. this will handle short current spikes but still protect short circuits and overload.
Combination of magnetic and thermal circuit breakers using this method of protection. the magnetic function is connected in series with the thermal parts. depending on the type of circuit breaker that the magnetic part uses is the instantaneous trip occurs briefly and the thermal parts take time to operate but are used to protect the circuit against sustained advantages and may take many seconds to operate depending on how much overload it is.
if you want to have a circuit breaker that gives one circuit circuit and fuse that feed on different set or if want to use circuit breaker and fuse in the same circuit.
If you want to use a separate circuit breaker from the circuit to fuse only feed from the main line circuit breaker to their circuit (s) and fuse from the main line to their circuit (s). someone will not be upset or affect others. each will protect the connected circuit.Now if want to use circuit breaker and fuse in the same circuit just feed the series. coming from the main line to the circuit breaker or fuse to the circuit or in reverse, fuse first.
I will not connect circuit breakers and fuses in parallel, around each other.