APPLICATION GUIDE 3-Phase Appliance Testing, using a Megger PAT320 or PAT420 The PAT320 & 420 are suitable for 3-Phase Appliance Testing. On our PAT testing machines, the live and neutral are connected together during the insulation test to ensure that there is no voltage applied between them (as 500Vdc applied to a 230Vac appliance would not be healthy) and then the leakage current, to earth, is measured and this is used to calculate the Insulation Resistance (ie: the quality and condition of the appliance’s insulation material). To achieve this, an adaptor needs to be made having the 3 phases (and neutral, if there is one) all connected together at the 4- or 5-pin 3-phase socket, and then wired to the neutral on the 10A 3-pin NZ plug which goes into the PAT tester. NB! The live in the plug is not connected to anything - this avoids danger if the adaptor was accidently plugged into a socket. See circuit diagram and examples below. 415V Adaptor lead (5 pin) to AU 16A 415V Adaptor lead (4 pin) to AU 16A With this adaptor you can now test a 3-phase appliance as though it was a standard, single-phase, appliance and you need to set up the test group as follows: Settings: (under Edit or Add a Group) Bond: 10A and <1ohm Insulation: 500V and >1Mohm NB! Leakage: Not applicable ! Load: Not applicable ! (make sure these are not selected) AVO New Zealand Ltd, P.O. Box 8921, Riccarton, Christchurch 8440. Ph 0800 485 990 www.avo.co.nz 3-Phase Appliance Testing, using a Megger PAT320 or PAT420 Most people would carry out a PAT test (for safety) followed by a function test to check operation. An Earth Leakage or Load test cannot be carried out by a PAT testing machine on a 3 phase appliance. In any case they are not really necessary - the CoP requires a full inspection followed by an Earth Test (on a class 1 appliance) and some sort of test to establish the integrity of the insulation. In most cases the insulation test fulfils this requirement, although sometimes a leakage / touch current test is carried out as an alternative. Some people (erroneously) carry out all the tests as a routine. You can also test 3-phase extension leads in exactly the same way you would test a single phase extension lead (but 3 times / once per phase) but with an adaptor that looks something like this: AVO New Zealand Ltd, P.O. Box 8921, Riccarton, Christchurch 8440. Ph 0800 485 990 www.avo.co.nz
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