Earth continuity test:
(dead test)

The Earth Continuity Test will ascertain whether the earth continuity between the earth supply to the boiler and the internal component earth connections and the metal casing of the boiler is earthed correctly.

1. Electrically isolate power supply at fused spur switch and remove fuse. (Always ensure the boiler is fused at 3 amps on completion of work)
2. Set multimeter on ohms scale for resistance readings
3. First, put the black lead from the multimeter to the retaining screws of the fused socket connection and then the red lead from the multimeter to the boiler casing.

The resistance reading must be no more than 1 ohm

Whenever the resistance reading proves to be more than 1 ohm, there is a fault present and must be traced and rectified before proceeding any further. Check all the earth wires for continuity and check all connections are secure.

Warning: Poor earth continuity or no earth continuity at all will create a dangerous situation, as any metal parts that should be earthed may become live and a short circuit may cause an electric shock

Earth Continuity Test for Heating Engineers and Boilers