RP 111C - Circuit Protection: General

The primary role of a circuit protection device is to protect a wiring system from over-current induced damage. It does this by opening in the circuit.

Locations with high exposure to environmental conditions and extreme ambient temperatures should be avoided. Where these conditions cannot be avoided, provisions should be made to offset their effects (e.g., shielding, ventilation, etc.).

Fusible links-although not recommended-  should not be located in the passenger compartment. They should be located in areas where the heat generated during the short circuit protection period will not permanently damage adjacent components.

Where practical, all circuit breakers and fuses should be located in one easily serviceable location with a means provided for identification of circuit function and current rating.

A primary protection device is one that protects the power feed circuits between the battery and the passenger compartment.

A secondary protection device is one that protects the wiring as well as switches, gauges, motors, and other functions in the passenger compartment.