Portable Appliance Testing (PAT Testing) is the term used to describe the examination of electrical appliances and equipment to ensure they are safe to use. Most electrical safety defects can be found by visual examination but some types of defect can only be found by testing.
Health & Safety Executive - Portable appliance testing
There are several main sets of Health and Safety regulations in the United Kingdom that apply to the inspection and testing of in-service electrical equipment:
The Health & Safety at Work Act 1974
The Management of Health & Safety at Work Act Regulations 1999
The Provision & Use of Work Equipment Regulations 1998
Electricity at Work Regulations 1989