INSULATION / PAT TESTING PROCEDURE
All electrical insulation within the Inverter Fusion Limited welding inverters provides Class II
protection in accordance with the international standard for arc welding power sources
IEC60974.
Portable Appliance Testing (PAT) as detailed in the IEE "Code of Practice for In-service
Inspection and Testing of Electrical Equipment", when applied to Inverter Fusion Limited
welders providing Class II protection requires the following tests and inspection.
(1) Visual Inspection (2) Insulation Resistance Testing (3) Functional Checks
1. Visual Inspection
To visually check that the equipment is in sound condition, check the following;
a) There is no damage (apart from light scuffing) to the cable sheath.
b) The plug is not damaged (the casing is not cracked or split and the pins are not
bent)
c) There are no inadequate joints in the cable (taped joints are not allowed)
d) The outer sheath of the cable is effectively secured where it enters the plug or the
equipment. Obvious evidence of damage would be if the coloured insulation of the
internal cable cores were showing.
e) The equipment has not been subjected to conditions for which it is not suitable, (eg)
it is wet or excessively contaminated.
f)
There is no damage to the external casing of the equipment or there are no loose
parts or screws.
g) There is no evidence of overheating (burn marks or discolouration).
2. Insulation Resistance Testing
To check that electrical resistances between the mains terminals and the user accessible
terminals are greater than 2MQ, the following test instrument and test procedure is required.
Test instrument
The resistance tester should apply a test voltage of approximately 500Vdc. The tester should
be capable of maintaining this test voltage with a load resistance of 0.5MQ.
Alternatively a PAT tester that can measure resistance with 500Vdc-applied voltage can be
used.
Procedure
a) The phase and neutral conductors are to be connected together. This connection is
best made with a dedicated test socket with phase and neutral connected together.
b) Connect one test lead to the phase/neutral pair. Connect the other test lead in turn
to each of the welding output terminals and the gas port on the front of the
enclosure and check that the resistance is greater than 2MQ.
Note
DO NOT FLASH OR HI-POT TEST
DO NOT PERFORM EARTH LEAKAGE TESTING
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