Fused Circuit Breaker
An integrally fused circuit breaker which combines the design and operating features of a circuit breaker and current-limiting fuse in one package.

Circuit Breaker
A device designed to open and close a circuit by non-automatic means and to open the circuit automatically on a predetermined overcurrent without injury to itself when properly applied within its rating.

Fuse
An overcurrent protective device containing a calibrated current-carrying member which melts and opens under specified overcurrent conditions.


Говоря по-русски, это ровно то, что раньше ставилось в квартирах: выключатель-автомат последовательно с "пробкой".