Portable appliance testing (commonly known as "PAT", "PAT Inspection" or (redundantly) as "PAT Testing") is the name of a process by which electrical appliances are routinely checked for safety. The formal term for the process is "In-Service Inspection & Testing of Electrical Equipment” (as defined by IET/IEE and City and Guilds). Testing involves a visual inspection of the equipment and any flexible cables for good condition, and also where required, verification of earthing (grounding) continuity, and a test of the soundness of insulation between the current carrying parts, and any exposed metal that may be touched. The formal limits for pass/fail of these electrical tests vary somewhat depending on the category of equipment being tested.
Health and safety regulations require that electrical appliances are safe and maintained to prevent harm to workers. Many equipment manufacturers recommend testing at regular intervals to ensure continual safety; the interval between tests depending on both the type of appliance and the environment in which it is to be used. The European Low Voltage Directive governs the manufacture or importation of electrical appliances. Compliance to this must be declared and indicated by the display of the CE mark on the product. The responsibility for this lies with the manufacturer or the importer and is policed by Trading Standards.
Testing equipment has been specifically developed for PAT inspections, based on the testing equipment used by manufacturers to ensure compliance with the British Standard Code of Practice and European product standards relevant to that type of appliance. This in turn allows testing and the interpretation of results to be de-skilled to a large extent. It has become accepted practice for individuals operating as PAT Testers to hold a 2377–22 City and Guilds qualification, which our PAT testers are fully qualified with.
Appliances British law (the Electricity at Work Regulations 1989) requires that all electrical systems (including electrical appliances) are maintained (so far as is reasonably practical) to prevent danger. Private houses are not covered by this legislation, although occupiers' liability requires householders not to deliberately expose occupants or visitors to unreasonable risks. The HSE and the local authority are responsible for the policing of this legislation.
Fixed wiring in buildings Guidance from the Institution of Engineering and Technology (IET, published under the IEE brand) and the Health and Safety Executive (HSE) recommends that a competent person must inspect the installation regularly in any public building or a place that people work. They suggest initial intervals for combined inspection and testing that range from three months (for construction equipment) to one year, and in many cases, longer periods for re-testing (certain types of appliance in schools, hotels, offices and shops).
Although the Electricity at Work Regulations 1989 is an obligation on UK businesses, there is no obligation to undertake PAT inspection. In reality neither act nor their corresponding regulations and associated statutory instruments detail PAT inspection as an obligation, but rather impose a requirement of maintenance of safety and evidence of routine maintenance for all hand-held, portable and plug-in equipment.