One of the most common questions PAT testing engineers receive is: how often do I need to have my equipment tested? The answer depends on three main factors — the type of appliance, the environment it's used in, and how it's used. There is no single legal requirement specifying a fixed testing interval; instead, the IET Code of Practice for In-Service Inspection and Testing of Electrical Equipment provides risk-based guidance that businesses and their insurers widely accept as the industry standard.
The IET Code of Practice: The Industry Standard
The Institution of Engineering and Technology (IET) Code of Practice is the definitive reference for PAT testing frequency in the UK. It classifies equipment by type (Class I, Class II, or Class III) and by the environment in which it's used (low, medium, or high risk), and then provides recommended maximum intervals between tests. These recommendations are not legally binding in themselves, but HSE inspectors, fire services, and insurance companies treat them as the accepted standard.
Class I equipment — which relies on an earth connection for safety — generally requires more frequent testing than Class II double-insulated equipment, which has two layers of insulation and no earth. Extension leads are considered high risk regardless of environment because they are frequently moved, flexed, and plugged and unplugged, making them more prone to damage.
Low-Risk Environments: Offices, Hotels, and Schools
- IT equipment (computers, monitors, laptops on stands): visual inspection only, every 4 years
- Photocopiers and printers: every 4 years
- Desk fans and portable heaters: every 1–2 years
- Extension leads: every 4 years (more frequent if visibly used heavily)
- Kettles and kitchen appliances in office kitchens: annually
- Chargers and power adaptors: every 2 years
Medium-Risk Environments: Retail, Hospitality, and Light Industrial
- Commercial catering equipment (microwaves, toasters, kettles): annually
- Vacuum cleaners in commercial premises: annually
- EPOS equipment and retail display units: annually
- Bar equipment (beer line fridges, glass washers): annually
- Power tools used occasionally in trade environments: every 6 months
- Commercial refrigeration: annually
High-Risk Environments: Construction, Industrial, and Agricultural
- Power tools on construction sites: every 3 months
- 110V CTE site equipment: every 3 months
- Industrial power tools in workshops: every 6 months
- Battery chargers (forklifts, vehicles): every 6 months
- Extension leads on construction sites: every 3 months
- Agricultural electrical equipment: every 6 months
Factors That Should Increase Testing Frequency
The IET recommendations represent maximum intervals, not targets. Several factors should prompt you to test more frequently. Equipment that is used by multiple different users is more likely to be mistreated. Equipment moved between sites or stored in vans is exposed to physical shocks. Equipment in wet, dusty, or corrosive environments degrades faster. Second-hand equipment of unknown history should always be tested before use, and any equipment that has been involved in an incident — a drop, a flood, an electrical fault — should be retested before returning to service.
Why Most Businesses Choose Annual Testing
While the IET guidance allows some equipment to go up to four years between tests in low-risk environments, the vast majority of businesses opt for annual PAT testing across all equipment. Annual testing simplifies compliance management — there is one date in the diary, one certificate to file, and one clear answer if an insurer or regulator asks when appliances were last tested. It also ensures that any equipment that has deteriorated during the year is caught before it becomes a hazard.
Setting Up a Testing Programme
An effective PAT testing programme starts with an appliance inventory. Before testing can be carried out, you need to know what equipment exists and where it is. A professional PAT testing company will create or update this inventory as part of the testing visit, providing you with a complete register that can be used for insurance, HSE, and auditing purposes. The register should record the appliance description, make and model, unique identifier, location, test date, test result, and next due date.
