Portable Appliance Testing (commonly known as PAT or PAT Inspection or PAT Testing) is a process by which electrical appliances are routinely checked for safety. The correct term for the whole process is In-service Inspection and 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.

If you look around your work environment you will see evidence of PAT testing in the form of safety labels attached to portable appliances such as IT equipment.

About PAT TestingPortable Appliance Testing

PAT Testing or portable appliance testing is an important part of any health & safety policy. The Health and Safety Executive states that 25% of all reportable electrical accidents involve portable appliances. The Electricity at Work Regulations place a legal responsibility on employers, employees and self-employed persons to comply with the provisions of the regulations and take reasonably practicable steps to ensure that no danger results from the use of such equipment. This in effect requires the implementation of a systematic and regular program of maintenance, inspection and testing.

The Health and Safety at Work Act 1974 places such an obligation in the following circumstances:
• Where appliances are used by employees.
• Where the public may use appliances in establishments such as hospitals, schools, hotels, shops etc.
• Where appliances are supplied or hired.
• Where appliances are repaired or serviced.

The level of inspection and testing required is dependent upon the risk of the appliance becoming faulty, which is in turn dependent upon the type of appliance, the nature of its use and the environment in which it is used. The Institution of Engineering and Technology publish the “Code of Practice for In-service Inspection and Testing of Electrical Equipment” This guide forms the basis for portable appliance testing in the United Kingdom.

Testing frequencies can cause concern with many companies testing for testing sake. British law states that all appliances need to be ‘safe’ (as far as is reasonably possible). This statement is very generic, so further advice can be sought from the Health and Safety Executive (HSE) and the Institution of Engineering and Technology (IET) who recommend PAT testing from 3 months for construction equipment and up to 2 years for office IT equipment for example.

It seemed inevitable with the increasing amounts of such equipment in domestic, commercial and industrial environments that the system employed would become more formalised and adopted as a method for assuring safety of appliances.


Portable Appliance Testing  (PAT Testing)

A system of formal, recorded visual checks and combined inspection and testing using a PAT testing meter. This is usually carried out on any equipment which has a plug, whether or not it is portable. (Portable handheld equipment is likely to need more frequent PAT testing than equipment which tends to stay in the same place)

Electrical Equipment

This includes anything used, intended to be used or installed for use, to generate, provide, transmit, transform, rectify, convert, conduct, distribute, control, store, measure or use electrical energy. It includes every type of electrical equipment, from a 400kV overhead line to a battery-powered hand lamp. (Electrical equipment includes conductors used to distribute electrical energy such as cables, wires and leads and those used in the high voltage transmission of bulk electrical energy, as in the national grid.)


An electrical system in which all the electrical equipment is, or may be, electrically connected to a common source of electrical energy, and includes such source and such equipment. It includes all the constituent parts of a system, such as conductors and electrical equipment in it, and is not a reference solely to the functional circuit as a whole.


Death or personal injury from electric shock, electric burn, electrical explosion or arcing, or from fire or explosion initiated by electrical energy, where any such death or injury is associated with the generation, provision, transmission, transformation, rectification, conversion, conduction, distribution, control, storage, measurement or use of electrical energy.