Fuses perform phase-by-phase (single pole) protection with a high break capacity at low volume. They limit I2t and electrodynamic stress (Icrête).
They are mounted:
- on special supports called fuseholders
- or on isolators in the place of sockets and links
The fuses used for motor protection are specific in that they let through the overcurrents due to the magnetising current when motors are switched on.
They are not suitable for protection against overload (unlike gG fuses) so an overload relay must be added to the motor power supply circuit.