A Beginner’s Guide to Portable Appliance Testing (PAT)

In-service Inspection and Testing of Electrical Equipment is the examination of electrical appliances and equipment classified as “portable” to ensure they are safe to use.

PAT testing legislation was originally put into effect to ensure that all businesses conform to the Health and Safety at Work Act  (1974), together with the Electricity at Work Regulations  (1989), the Provision and Use of Work Equipment regulations (1998) and the Management of Health and Safety at Work regulations (1999).

Conforming to PAT testing regulations helps those responsible for portable electrical appliances and equipment avoid violations.

Who is Responsible?

The law which embraces PAT testing requires landlords, employers, and the self-employed to make sure that their portable electrical appliances are both safe, suitable, and used for the purposes intended.

Indeed, all users of electrical equipment in the workplace have a responsibility to ensure that the electrical equipment they use has no obvious visual damage or defects.


Under the Health and Safety at Work Act 1974, employers have a responsibility to provide and maintain a safe plant for every employee to use.


This requirement is endorsed by the Electricity at Work Regulations of 1989 with its specific reference to electrical equipment. These regulations also place the same responsibilities on the self-employed.

What Should be Tested?

Portable appliances that need testing include any appliance that uses a flexible cable or plug and socket. This means that if there is an appliance that has a plug that is connected to a wall socket or generator, it should be PAT tested.

Equipment that should be tested include items such as electric drills, PCs, monitors, printers, kettles and larger pieces of equipment such as photocopiers and vending machines. Any cordless power tool would not need to be PAT tested.


However, its associated battery charger that plugs into the wall would need to be tested.

Larger, seemingly non-portable items, that nevertheless require testing include such items as heated towel rails and built-in dishwashers. These items qualify as portable because they also plug into a power source.

Power cords to IT equipment are required to be tested separately from the equipment they power as they are held to a different standard. Cable extensions are also tested as they are considered among the most common sources of safety hazards.

In advance of the testing of an item of equipment, the construction class should be determined so that the appropriate tests can be applied. Equipment usually falls into three basic classes, namely Class I, II, or III.

Class I equipment is connected to the protective conductor to prevent exposed conductive parts from becoming live should there be a failure in the basic insulation.

Class II equipment is constructed so that protection against electric shock does not rely only on basic insulation.

Class II equipment is frequently described as “double insulated” and should carry the symbol.

Class III equipment protects against electric shock through a supply from a separated extra-low voltage source (SELV).

How often equipment is tested depends upon its type and the environment it is used in. A power tool used on a construction site, for example, should be examined more often than a lamp in a hotel bedroom.

Who does the Testing?

In many low-risk environments, a competent member of staff can undertake visual inspections if they have the appropriate knowledge and training. However, when carrying out a combined inspection and testing, a greater level of knowledge and experience is required, and the staff member will need:

  • the appropriate equipment to carry out the tests

  • the ability to use the test equipment properly

  • the ability to understand the test results

The tester should have a sound knowledge and practical experience of electricity and its hazards. Beyond this, they should have an understanding of the necessary precautions required to avoid danger. They should also be able to determine whether it is safe for work to continue.

For testing purposes, the tester should be able to identify equipment and appliance types in order to determine the test procedures and frequency of inspection and testing required.


The tester should have the ability to create test records and take responsibility for the work and have an adequate knowledge of the required safety standards.

It is often the case that companies and public institutions such as schools will bring in an outside contractor to carry out the PAT testing.


This provides the reassurance that the testing is secure and the equipment is safe to use.


Although it isn’t a requirement, testers will often put a dated “pass” sticker on tested equipment that allows the employer or duty-holder to track the testing of individual items of equipment.

How is Equipment Tested?

A visual inspection should include checking against the manufacturer’s instructions that the equipment has been installed and used in accordance with these instructions.


Verification of the correct voltage, frequency, and current requirements should also be part of this inspection as should be a check that the ventilation or heat dissipation has been met.

The inspector should determine whether the environment is suitable for the purpose for which the equipment is being used or whether there is a risk of mechanical damage, exposure to weather, temperature, fluids, corrosives, or flammable materials.

It should be determined whether or not there is a suitable means of disconnecting the equipment from the mains supply, to carry out maintenance and, if applicable, in the event of an emergency.

The equipment tests are carried out in accordance with the equipment’s class categorisation and includes tests on earth continuity, insulation resistance, protective conductor/touch or alternative/substitute leakage, a functional check, a wiring polarity check, and a dielectric strength test.


Learn More with LMTS 

PAT testing should not be considered an irksome task and responsibility, it is the means by which an employer or duty-holder can look after the welfare of their employees in the workplace or members of the public visiting their establishment.

If you have concerns about how tests in your establishment should be carried out, get in touch with us today to get expert advice.