Portable Appliance Testing (commonly known as PAT or PAT Inspection or PAT Testing) is a process in the United Kingdom by which electrical appliances are routinely checked for safety. The correct term for the whole process is In-service Inspection & Testing of Electrical Equipment.
When people work with electrical appliances, health and safety regulations state that the appliance must be safe, to prevent harm to the 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 they use.