What is a 3 phase appliance?

How do you test 3 phase appliances?

Depending on the type of appliance, their are a number of different tests that are required to be carried out whilst testing 3 phase appliance to ASNZS 3760/2022.

Earth Continuity: Unlike single phase appliances, all 3 phase appliances in Australia are required to be earthed. This requirement is part of standard electrical safety regulations, like those outlined in the Australian Wiring Rules (AS/NZS 3000). The requirements and parameters for testing the continuity are outlined in ASNZS 3760/2022. When completing an earth continuity test, a measurement from the earth pin on the plug to the frame of the appliance must be recorded. This can be completed via point to point probe testing using our Metrel BT3309 PAT Testers. The reading must return a result less than 1oHm of resistance.

Insulation Resistance Testing: Similar to single phase, insulation resistance testing is still required. 3 phase appliances however require insulation resistance testing at each phase terminal (L1, L2, L3) against the earth terminal and between each pair of phases (L1-L2, L2-L3, L3-L1), ensuring all readings exceed 1 MΩ or meet the manufacturer's specifications. It is important to always make sure that the appliance is isolated, capacitors discharged, and sensitive electronics disconnected before testing.

Clamp/differential Leakage Testing: Certain appliances if safe to do so will require clamp/differential earth leakage testing. This is where the earth wire is tested via the clamp to determine if there is any current on the earth. If there is more than 5mA detected, then the appliance would fail and not be considered safe to use under ASNZS 3760/2022.