Portable appliance testing

Portable appliance testing (commonly known as "PAT", "PAT Inspection" or (redundantly) as "PAT Testing") is the name of a process in the United Kingdom, the Republic of Ireland, New Zealand and Australia by which electrical appliances are routinely checked for safety. The formal term for the process is "in-service inspection & testing of electrical equipment". Testing involves a visual inspection of the equipment and any flexible cables for good condition, and also where required, verification of grounding (earthing) 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.

Similar procedures exist in other countries, for example, testing of equipment according to DGUV Vorschrift 3 in Germany.

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 has to 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. The inspection of the appliances can largely be carried out in-house in many organisations. This can result in cost savings and more flexibility as to exactly when a PAT is carried out.

Portable appliance testing is abbreviated as PAT. The correct term for the whole process is "In-service Inspection & Testing of Electrical Equipment" (as defined by IET/IEE and City and Guilds). In Australia, the common name for PAT is simply 'Test and Tag'. The regulatory guidelines are set out in AS3760:2013.

Appliances British law (the Electricity at Work Regulations 1989) requires that all electrical systems (including electrical appliances) are maintained (so far as is reasonably practicable) 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.

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