Portable Appliance Testing

Portable appliance testing (commonly known as "PAT", "PAT Inspection" or "PAT Testing") is a process in the United Kingdom, the Republic of Ireland, New Zealand and Australia by which electrical appliances are routinely checked for safety. The correct term for the whole process is "in-service inspection & testing of electrical equipment".

Similar procedures exist in other countries, for example, testing of equipment according to BGV A3 in Germany.

Health and safety regulations require that electrical appliances are safe to prevent harm to workers. Many types of equipment require testing at regular intervals to ensure continual safety; the interval between tests depending on both the type of appliance and the environment it is used in.

Evidence of testing is clearly visible to workers in the form of "passed", "tested for electrical safety" and "do not use after..." labels affixed to various parts of the electrical equipment used.

Portable appliance testing and inspection was, however, conducted on a 3 month (high risk) and 6 month (low risk) cycle from the early 1960s onwards. This was under the control of DOEPSA—the Department of the Environment Property and Services Agency (circa 1970 to 2000)—prior to that it was known as the Ministry of Public Buildings and Works (MOPBW) until about 1970.

Extensive record keeping was made into log-books and generally the equipment used was an insulation resistance tester, simple hand tools and visual inspection. This testing and inspection was done under a planned maintenance scheme and predated both the Health and Safety at Work Act 1974 and the Electricity at Work Act 1990 that are frequently quoted as the reason that PAT inspection is done.

In reality neither act nor their corresponding regulations detail PAT inspection as an obligation, but rather state a requirement of maintenance of safety and evidence of routine maintenance for all hand-held, portable and plug-in equipment.

Testing equipment specifically designed for PAT inspections was developed using portable devices, which were based on the testing equipment used by manufacturers to ensure compliance with the British Standard Code of Practice relevant to that type of appliance.