Question

Fuse wires of miniature circuit breakers are not used in a circuit containing electric cells. Why?

Answer 1

MCBs are most commonly used in place of fuses because it is easier to turn on an MCB when it gets tripped.
In a circuit where electric cells are used to supply low values of voltage and current, no fuses are required because there is very little risk of short circuit. To avoid any accident, these fuses are used in circuits where high voltages and currents are delivered.