The earth continuity test allows for verification of the connectivity between any exposed metal parts and the protective earth pin in the mains plug of a class 1 appliance. This involves connecting the item of electrical equipment to the PAT tester, and the test probe to exposed metal parts. A current is then transferred from the PAT tester along a mains cord to the enclosure. This current then flows back to the PAT tester via the protective earth conductor. This will result in the display of the protective earth path resistance.

A Fuse of the correct Rating for the Appliance to work safely is checked and the cable if any is also visually checked

The PAT testing of IT equipment is conducted much the same as standard appliances but care must taken not to use excessive bond test current or use a 500 V insulation test. IT equipment generally uses the thin internal printed circuit board to provide interconnecting earth points so a bond current of 10 amps or more would burn out these tracks. In addition IT equipment mains supply inputs have suppression components that would be destroyed with an insulation test in excess of 250 V. Generally a continuity test current of 100 or 200 mA is considered the maximum and an insulation test 100 or 250 V is recommended.

Battery Operated Tools? Battery-operated equipment and cordless equipment (for example, power tools) do not need PAT testing, as they are not powered by mains electricity. However, any battery chargers that power the equipment would need testing as these plug into the wall and charge the equipment.