09. Aren’t electrical cables protected by circuit breakers or fuses?
While circuit breakers and fuses can provide thermal protection for the cable insulation, they are unable to protect cables from mechanical damage. Even with overcurrent protection devices that offer an “instantaneous” protection setting, irreversible cable damage will typically occur in inadequately restrained cables within the first half cycle of the fault initiation (i.e. before circuit breakers can interrupt the fault). In the case of fuses, the restraint system must withstand the forces associated with the maximum let-through current. In most cases, overcurrent protective devices for power cables are adjusted with intentional time-delay for system coordination with downstream devices, which increases the potential for mechanical damage in inadequately restrained cables.
All cables that are exposed to potential short circuit current should be restrained by Talon® cable cleats. Talon® cable cleats protect high voltage, medium voltage and low voltage cables from mechanical damage resulting from short circuits.