What Is PAT Testing Mainly Used For?

Typical portable electrical appliances found in a workplace include drills, hair dryers, vacuum cleaners, buffing machines, power saws, photocopiers and laptops, to name but a few! Electrical items that are not considered to be portable appliances include such things as ceiling lamps and cookers that are hard-wired into the mains supply.

There’s no legal requirement as such in UK law to PAT test electrical equipment, but it does come under health and safety law, in the form of the Electricity at Work Regulations 1989. These regulations require all electrical systems, including items of portable electrical equipment, to be maintained so they don’t become dangerous. PAT testing is a way to meet this requirement. There’s no legal timeframe as to when appliances should be tested and at what intervals, but many employers test appliances on an annual basis, or more frequently if they’re exposed to harsh conditions (e.g. used outdoors or in wet, hot or cold environments).

Ultimately, the frequency of testing should be determined by a risk assessment for each item of equipment. Risk assessments are a legal requirement, according to the Management of Health and Safety at Work Regulations 1999. A good risk assessment for a piece of portable equipment must identify the main risks from using the equipment, to spot items at a greater risk of losing their integral safety through damage, misuse or degradation. The risk assessment must also put in place control measures to minimise risk. PAT testing is one example of a control measure to decrease risk. The higher the risks identified in the risk assessment, the more frequently PAT tests should be carried out, along with other control measures to decrease risk.

The actual testing procedure for portable appliances includes a visual inspection, as well as a test using a special PAT testing instrument. The visual test should check the condition of cables and wires, integrity of the casing and the plug. PAT test instruments carry out more detailed checks on equipment. Mains powered PAT testers are used, as well as battery operated testing devices. These are self-contained and easy to use. They perform an earth continuity test, insulation resistance test and a check on the wiring of the mains cord. They can also include tests that power up the appliance so it can be tested when connected to the mains supply. Most testing machines use a straightforward pass or fail result. As well as their pass and fail message, they have different settings for metal and plastic appliances, analysing earth continuity, polarity and insulation resistance.

More advanced PAT testing machines are available and are able to provide more detailed information about the appliance, with more sophisticated testing features. These are mainly aimed at more complex portable appliances with a higher element of risk when used at work. Advanced PAT testing devices display more information than a simple pass or fail message. Their earth continuity resistance test gives a more sophisticated measurement range and can cope with lower test currents, which enables a wider range of appliances to be tested (e.g. computers, which are sensitive to normal PAT testing). They can also carry out insulation resistance tests at voltages of 500 V DC and 250 V DC, earth leakage tests, fuse tests and lead polarity tests.

Of course, all results from a PAT test need to be interpreted by someone who’s competent to do so. Competency is defined in health and safety law as having sufficient knowledge, training, skills and experience to carry out a certain task correctly and safely. Visual inspections can be carried out by the equipment users themselves. Electricians have to pass stringent examinations to qualify for their trade and the readings from an official PAT test need to be interpreted and logged, which is usually best carried out by an electrician or someone who as enough skill and time to get around even the largest of workplaces. PAT testing makes up an important part of facilities management because it can record the location and safety status of portable electrical equipment. Most large employers contract out their PAT testing to an electrical contractor on an annual basis, to a company like Fluke Ireland.