4. Polarity Test
Polarity tests are carried out to ensure the correct connection of active, neutral and earth conductors to electrical equipment and to ensure that switches are not installed in neutral conductors. Clause 18.104.22.168 “Polarity” of the Wiring Rules specifies the testing requirements for this mandatory test.
To carry out these tests, a continuity tester such as a multimeter (set to ohms) should be used.
To ensure that the installation circuits/equipment will function as intended, it is necessary that the following tests be performed:
• Isolate the active conductors by turning the main switch OFF and tagging.
• Confirm consumer and sub mains cables/connections by simply testing from the point of supply or distribution board to the main switchboard using an ohm meter and long test loads. Test result ≈ 0 Ω.
• Confirm active conductor switching by using an ohm meter with the long lead connected to the active conductor at the switchboard and the short lead connected to the switch terminals (one at a time) in the following manner:
i) Switch ON ≈ 0 Ω for both terminals
ii) Switch OFF ≈ 0 Ω for one terminal and ‘infinity’ for the other terminal
• With the MEN link in place, confirm the polarity of socket outlets using a 10Ω resistor and an ohm meter. Connect the 10Ω resistor between the circuit active conductor and the neutral bar then at each socket outlet connect one lead of the multimeter to the earth terminal and the second lead to the active terminal. Test the resistance value for:
i) socket outlet switch OFF ≈ ‘infinity’
ii) socket outlet switch ON ≈ 10Ω.