10
3
4.4 Polarity Test.
Upon completion of the Earth-Loop Impedance Test, a Polarity
Test should be conducted so as to confirm that the supply
system is correctly connected. Place a finger firmly on the
‘Touch Pad’ (See Figure 6) and maintain pressure for a few
seconds. The 3 LED’s of the ‘Correct Wiring Indicator’ will
remain green to indicate correct polarity. Incorrect Polarity is
indicated by the 3 LED’s intermittently flashing Red.
Figure 6.
Any failures should be investigated. This will normally be the
responsibility of the electricity supply company who should be
advised accordingly.
Checking the Earth-Loop Impedance will measure the
resistance of the earth path used by a current flow during a fault
condition. It will ensure that during any fault condition, the flow
of electricity to earth will be sufficient to cause the circuit
protective device e.g. fuse or circuit breaker, to rapidly halt the
flow of electricity through that circuit.
2. Instrument Overview
Figure 1.
Correct Wiring Indicator
Wiring Indicator
Reference chart
Voltage Indicator
Earth - Loop Indicator
Polarity Test Pad
Earth-Loop Test Button
