What is PAT Testing?

I’m sure most of us will have seen those little ‘passed’ labels which are (or should be) clearly visible on many electrical items in most offices. They can be found on the kettle, toaster, monitors and electric paper shredders, lamps and desk fans; but what are they for? Well the answer is that these little green labels mean the appliance to which it is attached has be PAT tested by a competent PAT engineer. PAT testing means Portable Appliance Testing and is a simple electrical test conducted on most items of electrical equipment used in the workplace, schools, shops, museums or any other public building.

Almost all electrical appliances in such settings needs to be deemed safe for use on a regular basis and the person responsible for ensuring this is done is the 'duty of care' holder. This is usually the most senior person in a business or organisation; however the 'duty of care' holder could be another appointed person with the organisation. PAT testing should really be carried out by a competent PAT engineer who is fully aware of the current PAT testing regulations.

Electrical appliances need to undergo a visual inspection where the power cable and plug are inspected for visible signs of wear and tear, as is the casing of the appliance being tested. Assuming all is well regarding the visual inspection, the appliance is tested more thoroughly using a PAT tester. This is an electronic device into which the appliance being tested is plugged in order to carry out basic safety tests such as earth continuity, insulation resistance and polarity.

Basic PAT testers are available which simply state whether an appliance passes or fails the test and can be used by non electricians. However most PAT engineers use a more advanced PAT tester that gives more detailed information than simply 'pass' or 'fail' and should be used only by qualified PAT engineers. PAT testers also need to be calibrated regularly in order to ensure they are measuring correctly so the tests remain compliant with current PAT testing regulations. Failure to make sure a PAT tester is calibrated on a regular basis could negate or void a companies or individuals electrical testing data.

Although one can carry out their own PAT testing, it's highly advisable to hire an experienced testing PAT engineer to do it for you. They will offer a far more comprehensive service than a layman can provide and in the event that any appliance fails the test, may be able to repair it in the spot or advise whether a repair or replacement is required.