PAT testers are qualified people who run a series of tests on electrical equipment to make sure that they are not malfunctioning and performing as intended. Not everyone is qualified to become a PAT tester because testing requires an understanding of the testing equipment and the appliances being tested. The best way to become competent is to attend a PAT testing and tagging course and have a bachelor’s degree in electronics.
This is a practical manual that offers a complete code of practice for an in-service inspection and the testing of electrical equipment. This will often include advice on safety legislation, health and compliance issues. Every testing and tagging professional needs to be very familiar with this manual prior to testing anything.
The correct testes in the correct order ensure that the results you receive i.e. pass or fail are accurate. This also saves you from errors which may end up making you redo the testing.
When you purchase high quality PAT testing equipment there will be no doubt about the test results. Testers are urged to avoid buying second hand equipment and to always get their equipment re-calibrated every few months.
If you are trying to reach your monthly testing bonus the worst thing you can do is to rush through the tests. Usually PAT testers will get a bonus for the electrical appliances they test but rushing through things means that you’ll make mistakes which could jeopardize your job or your business.
Most tests will pass but a tester shouldn’t assume this. Your job is to not assume that the appliance will pass but to go through the whole testing sequence. That said you shouldn’t simply touch an appliance because that would be a good way to receive a nasty shock. Always be prepared by wearing gloves if you really need to touch the appliance.
During testing and tagging many appliances testers often make the mistake of putting a ‘Pass’ label on a failed appliance because they cannot be bothered to fill out the failed sheet in their records. This type of thing is illegal and if the appliance is in fact dangerous which causes personal harm you’re going to be in big trouble.
Perhaps one of the biggest most common mistakes that many testers make is when testing the insulation of a Class I appliance. Because you do not know that the conductive earth path is working you cannot rely on the insulation test since you’ve not tested the earth path yet to make sure it is good.
You could have a situation where a live wire has been broken from inside of a portable appliance which is now touching the outer casting. Once you have performed the insulation test and made sure that everything inside is around 500V you now need to find leaking voltage. So, if the appliance has not been turned on there is no current running through the live wire and so nothing will escape which will result in a false ‘Pass’ of an otherwise dangerous appliance. You should also be careful not to test the appliance as a 500V shock is pretty severe.
There are some appliances that have more than one outer part with separate earthed ends. This will require that you test each one independently. Also when dealing with multiple earth paths you should consider the worst case scenario as opposed to the average reading.
There are times when you need to perform an insulation test multiple times. The best solution is to wrap a device in kitchen foil and then perform the insulation test on this kitchen foil.
These appliances have no earth and so your testing will definitely fail. But you should check if you’ve got the right type of appliance when running a PAT test.
Citations: Inspection, testing, tagging & repairing electrical equipment - OHS information sheet
Mark is one of the leading PAT testing and tagging experts in Sydney. He runs his own testing and tagging service catering to both home owners and businesses alike.
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