Overcurrent, short circuit and earth fault protection

Overcurrent, short circuit and earth fault protection... 

Circuit protection devices, such as fuses, breakers, or fault-interrupters, may be required in case of excessive current draws as a result of a short circuit, overcurrent, or earth fault. Several options exist with circuit breakers preferred over fuses. In some of the newer devices several functions are combined into one, thereby reducing the total number of components. An example of this is a combined power-switch/circuit-breaker. The switch/breaker is used as a switch and breaker and senses each line and opens all lines, except the grounded line, simultaneously when a fault current is present. Also, the switch/breaker looks and functions as a standard power ON/OFF rocker switch. In some standards simultaneous interruption of the phase and neutral is required, thereby, precluding the use of fuses. 

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