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How to Guide for Portable Appliance Testing

PAT testing equipment

Depending on the appliance you’re testing, it may take up to 1 hour to do PAT testing.

What you’ll need

Portable Appliance Testing (PAT) test equipment is used for testing portable appliances to ensure that they meet standards. There is various PAT testing equipment available, whether for basic or professional use.

The type of equipment you’ll need for PAT testing depends on the number of appliances, individual testing functions, and the professional level of testing that the test would require. For example, if you are only testing a few appliances, you may want to consider the basic and less expensive testing equipment.

However, if your testing would involve professionally assessing over 300 appliances, then you will need to procure specialist testers, which are often costlier than the basic types.

A simple PAT tester will allow you to perform around 300 tests, while mid-range PAT testers come with additional features. Professional PAT testers can download and have features that allow for the saving of testing information.

What is PAT Testing?

Portable Appliance Testing (PAT) testing involves the assessment of portable electrical appliances to ensure they are in the right working condition and are safe to use. In the UK, legislation requires businesses to maintain electrical appliances in a safe condition. Therefore, landlords, offices and business places, construction and manufacturing sites, healthcare centres, hotels and restaurants, self-employed people, and even homes need to make sure that their portable electrical appliances are safe and suitable for use.

Electrical appliances are divided into three classes, namely: Type I, Type II, and Type III.

Type I: Type I appliances are the most dangerous of the three categories of electrical appliances. They have only the essential insulation, which relies on earth. Examples are photocopiers, computers, washing machines, refrigerators, kettles, irons, toasters, etc.


Type II: Type II appliances are safer to use since they have extra insulation and do not rely on earth for protection. Examples include TVs, lamps, lawnmowers, drills, hairdryers, etc.

Type III: Of the three categories of appliances, Type III appliances are the safest to use. They are low-voltage equipment and may not sometimes require PAT testing. Examples are mobile phones, cameras, laptops, torches, etc.

PAT testing involves assessing the condition of the components of electrical appliances, such as:

  • the cable
  • external casing
  • plug
  • and carrying out insulation tests.

Ensuring the safety of portable electrical appliances is important because poorly maintained or faulty electrical appliances can cause electric shocks, burns, or fires. Preventing such hazards is the responsibility of the employer, and an employer may be held liable if they fail to comply with the regulations.

PAT tests help to keep everyone in the work (and home) environment safe and help prevent paying fines or even legal fees in the event of a lawsuit.

While there are no hard and fast rules as to how frequently PAT testing should be, how often an appliance is tested depends on the type of appliance, where it will be used, the risks such an appliance poses, and how often it’s used.

PAT testing usually involves three stages, namely:

  • informal checks by the user of the appliance
  • inspection of the equipment (visual)
  • Examination of the equipment (manual)

You don’t have to be a qualified electrician to inspect appliances and PAT testing. In a low-risk setting, you can carry out the visual inspection yourself if you have the skills to do it.  However, when carrying out visual inspection and testing, you’ll need to have the right level of knowledge and experience to properly carry out the task. Portable Appliance Testing is an important task that can pose serious hazards to the users when done incorrectly.

Therefore it is strongly recommended that you take a PAT testing course and obtain a certificate of competence if you don’t have the knowledge and skills to carry out the task.

The following are essential if you want to carry out visual inspection and testing:

  • The right equipment to carry out PAT testing
  • The ability to use the test equipment proficiently.
  • Should have the ability to evaluate whether it is safe to do a PAT test.
  • Good knowledge of electricity and experience in electrical work.
  • Ability to understand potential hazards and precautions to take when carrying out the test.
  • Ability to read and understand the test results

How to Carry Out a PAT Test

The first step is regular, informal checks by the electrical appliance user. At this stage, signs of damage and potential risks are checked. The next step of the testing is the formal visual inspection. This step usually helps in detecting the majority of the problems with appliances, and it is done by checking the following:

The appliance: Check the appliance for any cracks, burns, corrosion, wear, and tear.

The plug: Assess the plug for any indication of burns or damage. Also, check for bent pins. Assess the wires and make sure they are in order and that the live, earth, and neutrals are tightly connected to the respective terminals.

The cable: Assess the cable for the presence of cuts. Also, check for the presence of abrasions.

Residual Current Device (RCD):

  • Look for any indication of damage in the RCG:
  • Check the standard current at which RCD operates, and
  • Look at the ‘test’ button to ascertain it’s in order.

Environmental checks:

  • Look out for trip hazards from cables.
  • Check that the extension leads are not overloaded.
  • Also, carry out a risk assessment for water and fire.

The next step, which is the manual examination of the equipment with a portable appliance testing device, can be done as follows:

Test for earth resistance

To carry out the earth resistance test, measure the resistance given when the connection leads face the earth rods. If the earthing resistance is below 1Ω, the appliance has passed this aspect of the test.

Test for the continuity of the earthing.

To do this, use an ohmmeter to measure the appliance’s protective resistance to the earth circuit below 1Ω.

Test for insulation resistance.

For this test, a rated voltage with a value of between 5mA and 1mA is performed to check for current leakage. Next, use the PAT tester to apply a simple voltage to the appliances’ live conductors. You can also use an ohmmeter to carry out a test for insulation resistance.

Safety switch test

You can carry out this test in two ways. The first method is by using a Residual Current Device (RCD) tester. The tester is connected to an earth terminal. Next, select the testing range delta, followed by half the delta range, and finally the delta range, where the RCD should begin to operate.

The second method is by using an applied current test. In this way, a current that is the same as the estimated tripping current is swiftly applied between the protective and active earth, and the operating time is measured. With this method, Type I appliances should have a maximum of 40ms, while Type II appliances should have a maximum of 300ms.

Reporting on the PAT testing

After you’ve carried out the inspection and testing, you need to give a report depending on the level of testing that you’ve done and the use of the appliance. Your report should include the type of appliance you’ve tested, its name, location, and a full description.

Your report should also include the test results of each appliance and include reasons for when an appliance fails the test. Finally, stick a label on the appliance that would show whether or not the appliance passed or failed the test. If an appliance fails the test, it must be removed for repair or completely replaced. A repaired appliance must be tested again before it is approved for use again.

If you do your own PAT testing, you must, however, understand that you’d need paperwork to confirm your equipment is safe. An approved PAT testing company should be able to issue you a PAT certificate.

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