Contrary to popular belief, there is no legal requirement specifically for PAT testing of electrical equipment in either the workplace or, in the case of any landlord or company-supplied electrical equipment in rented accommodation, or residential care homes, etc*. However, as we shall see, it is indeed a legal requirement that such electrical equipment, and in particular the items being used in the workplace are, in simple terms, 'safe, well-maintained and suitable for the purpose for which it is being used', at all times. As a business owner or facilities manager, you need to think about how you would prove this.
It should be pointed out that most business premises are also workplaces, therefore the Health and Safety at Work Act 1974 (HASAWA) applies. HASAWA even applies in a private home, where employees such as care workers are being sent to fulfill a contract. HASAWA is one of the few pieces of legislation that carries 'reverse onus of proof'. This means that in the event of an accident or incident, the business owner is guilty until proven innocent. The onus is on the business owner to prove that all reasonably practicable steps were taken to ensure the safety of employees and all other persons using the premises, and inspection and testing records are one way of proving this.
Electrical equipment must at all times be 'safe, well-maintained and suitable for the purpose for which it is being used'. And the penalties for non-compliance can be severe: in certain cases, unlimited fines and imprisonment, not to mention private prosecution when someone has suffered a serious electric shock, or the damage done to property in the case of a fire. More than 2,500 people are either killed or injured as a result of electrical fires in the UK each year, and more than thirty people are directly killed by electric shock. A well organised electrical testing regime is not 'health and safety gone mad'. It is a sensible business decision, and should be given the same priority as business insurance.
The only way to determine whether electrical equipment is 'safe, well-maintained and suitable for the purpose for which it is being used' (the legal requirement), is if it is routinely, formally visually-inspected and instrument-tested ('PAT Tested'). And records of these inspections should be retained as evidence of a structured inspection regime. Therefore, PAT Testing is the best way to ensure that such equipment, at the time of the inspection and testing at least, is indeed 'safe, well-maintained and suitable for the purpose for which it is being used'.
Look across the room now at a piece of electrical equipment, perhaps a computer, water cooler, toaster, fridge, etc. Can you tell if its earth wire is internally in contact with the exposed metal work? How good is the insulation? What is the condition of the wires inside the plug? Are the live and neutral wires reversed at either the plug end or inside the appliance? (the appliance would still function with 'reversed polarity', but it is potentially very dangerous). Is that slight shock that you and your colleagues get from that fridge several times a week really just static? Without formal visual inspection and testing, how can we know if equipment is safe, whether it needs to be repaired or disposed of, or otherwise appropriately dealt with? In other words, whether it is compliant with legislation.
Finally, there is specific legislation for certain more hazardous workplaces, such as construction sites. The Construction and Design Management Regulation 2015 are European regulations that are imposed in addition to HASAWA to control risk on building sites. Previously only for very large construction projects, the 2015 update of the CDM Regs brought all domestic refurbishment work into scope, requiring all 240V tools and cables to be inspected every 12 months, and all 110V tools and cables to be inspected every 90 days. If your employees work on site, or in a domestic setting, power tools should be inspected at these intervals, and records kept as evidence in case of inspection by the Health and Safety Executive, or in the event of an accident or incident.
*NB. There is just one exception to this: Regulation 6 of The Provision and Use of Work Equipment Regulations 1998 (PUWER) requires that equipment has to be 'inspected' in work situations where the safety of the equipment depends specifically on the installation conditions, and, in particular, where conditions are liable to lead to deterioration. This is a very specific requirement, for a very specific situation, and yet even here, there is no mention of the word 'testing'.