5.6 Continuity

Tests are conducted to ensure continuity of the earthing system. This is to ensure circuit protective devices operate properly if a fault occurs between live parts and earth. A continuous earthing system also ensures exposed parts of electrical equipment do not reach dangerous voltages during faults. The resistance of protective earthing conductors must allow circuit breakers to operate properly. It must also be consistent with the conductor length, size and material. The main earthing conductor and bonding conductors must have resistance of less than 0.5 ohms. Further tests determine the maximum allowable resistance for each circuit's protective earthing conductor.