PAT = Portable Appliance Tester
A PAT is essentially a number of testing instruments built into one case designed specifically for one main purpose; the easy, quick, and accurate testing of appliances/electrical equipment.
Portable Appliance Testers do not have multiple test leads to be inserted or attached unlike other types of test equipment. The appliance simply plugs into the PAT and one fly lead normally referred to as the ‘wander lead’ is attached to the equipment being tested. After the appliance has been tested the PAT will indicate the results as a pass or fail (and may also, depending on the tester, give actual readings) therefore no interpretation of results is usually required.
A combination of other test instruments can be used instead of a PAT but this complicates and slows down the process of testing. More time is then required to test and more training is needed by the operator. Hence the reason a PAT is normally used.
Choosing a PAT over a variety of individual testing instruments for electrical safety testing is like choosing a chainsaw over an axe for felling a forest. You may already own the axe and it is cheaper initially, but the speed, practicality and ease of use make the chainsaw preferable. It is the speed, practicality and ease of use of most PATs that makes them the preferred choice for electrical testing. For the non electrician (‘competent person’) it is the only choice.
There is a wide range of PATs available ranging from simple ‘PASS’/’FAIL’ testers to fully functional label printing SupaPATs™ which produce really tough tags.
The most basic (and usually cheapest) PATs often only indicate whether a test is a
‘pass’ or ‘fail’ without showing the tests actual values – you have no way of knowing how close to a fail the test really was! They usually have very limited test options and the earth bond test is normally only done at 100/200 milliamps. This test current, whilst ideal for IT equipment, is not, in our opinion, suitable for non IT Class I equipment (ie things like fridges, bench grinders, microwaves, concrete mixers, etc). These testers we refer to as ‘compliance testers’ and are fine if you are testing for compliance, but we believe that safety along with compliance should be the goal. There are still some PATs in the cheaper price bracket that do test for compliance and safety with a 10/25 Amp earth bond test but it is, however, also becoming common for the more expensive, feature rich testers, to be ‘compliance testers’ as well being only capable of an earth bond test at 100/200 milliamps.
A PAT tester with a 10 or 25 Amp earth bond test is getting less common (available) for two reasons:
- First is price: it is much cheaper to produce a PAT without the high current earth bond test.
- Second is size: people want smaller, lighter, more portable testers and a high current earth bond test adds both size and weight to a PAT.
However, at Metrotest we believe that convenience should not result in a decrease in safety. While cheaper and lighter might seem preferable; the convenience of your cheaper and lighter test equipment will be of no comfort to the person electrocuted because of an earth failure.
Remember it is the protective earth on a Class I appliance that is paramount to its’ safety. Click here to read more about the importance of Earth testing on Class 1 appliances. Click here to see an Earth Continuity Test in action
The most advanced PAT Testers store results in on-board memories with results then being able to be sent to a computer and many have the ability, with the addition of a printer, to produce tough tags using information from the testing, eliminating the need to hand write tags.
You will also see within this web site the term ‘SupaPAT™’. This is not just a PAT but a whole interactive testing system designed by Metrotest and ‘SupaPAT™’ describes our advanced, fully auditable PAT testing systems. This is not just a system that the techs/manufacturers have put together, but this has been developed from years of actual in the field testing. New features are being added to these all the time and it is our aim to have the fastest most accurate and auditable PAT safety testing system.