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Electrical Safety Testing
The tests
Earth bond test.
Applies a substantial test current, typically around 25A, down the Earth pin of the plug to an Earth test probe, which should be
connected by the user to any exposed metalwork on the casing of the unit under test. From this the resistance of the Earth bond
is determined.
Insulation test.
Applies a test voltage, typically 500Vdc, between the live and neutral bonded together and Earth, from which the insulation
resistance is calculated.
Other tests offered include the following:
Flash test.
Tests the insulation at a higher voltage, typically 1.5KV for Class 1 appliances. From this test a leakage current indication can
be obtained. This is a more stringent test of the insulation that can provide an early warning of insulation problems developing
in the appliance. (It is recommended that this test should not be carried out more frequently than quarterly to avoid over
stressing the insulation).
Load test.
Measures the load resistance between live and neutral to ensure that is not too low for safe operation.
Operation test.
A further level of safety testing which proves the preceding tests were valid (i.e. the unit was switched on) and ensures that an
excessive current level is not drawn by the appliance.
Earth leakage test.
This is carried out during the “Operation test” as a further test of the insulation under its true working conditions. This test can
also be useful to ensure that appliances are not responsible for nuisance tripping of Earth fault indicators.
Fuse continuity test.
This will test that the fuse is intact and that the appliance is switched on prior to carrying out other tests.
The procedures for portable appliance safety testing require that electrical tests are carried out upon the appliances to confirm
the integrity of the earthing and the insulation. To simplify this task a competent person can use a portable appliance tester
which combines all these tests (P.A.T currently available for 230V 50 Hertz) to perform these tests safely.
Current guidelines require that the trolley be P.A.T. tested at a minimum of 6 monthly intervals. This may vary dependent on
local and national laws and to site conditions and should only be carried out by Burlodge or authorised personnel.
CAUTION:
Electrical Safety Testing by untrained personnel may cause permanent damage to the electronics if not carried out correctly.
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