PAT testing (portable appliance testing) is the inspection and testing of electrical equipment that plugs in: kettles, computers, extension leads, power tools, hair dryers, microwaves, heaters. Most faults are found by a careful look at the plug, flex and casing. The electrical tests then find what you can't see, like a broken earth or failing insulation.
There is no law that says "PAT test every 12 months". The Electricity at Work Regulations 1989 and the Provision and Use of Work Equipment Regulations 1998 require equipment to be maintained in a safe condition, and landlords must make sure the appliances they supply are safe. How often equipment is checked should depend on the risk. We'll help you set sensible intervals rather than test everything every year by default.
What each test involves
- Formal visual inspection: plug, fuse rating, cord grip, flex, casing, and signs of overheating or damage. This finds most faults.
- Earth continuity: for Class I (earthed) equipment, proving the earth path from the plug to the metal casing.
- Insulation resistance, or a leakage test where switching on the item matters: checking the insulation hasn't broken down.
- Polarity: for extension leads and IEC leads, where reversed wiring is surprisingly common.
- Functional check: does it work as it should?
Double-insulated (Class II) items, marked with the square-in-a-square symbol, don't have an earth, so the visual inspection matters most for them.
How often to test
The right interval depends on the equipment and where it's used. The IET Code of Practice for In-service Inspection and Testing of Electrical Equipment gives starting points, and HSE guidance for low-risk premises is clear that a lot of office equipment needs less than people assume. As a rough guide:
| Environment | Typical starting interval |
|---|
| Office IT and desk equipment | Visual checks regularly; testing every 2–4 years may be enough |
| Office kettles, heaters, extension leads | Every 1–2 years |
| Rented homes (supplied appliances) | Each change of tenancy, or yearly in HMOs |
| Salons, commercial kitchens, schools | Every 6–12 months |
| Construction site 110 V tools | Every 3 months |
Our guide How often does PAT testing need doing? goes into this in more detail.
Your records
Every item gets a pass or fail label with a unique ID and the test date. You receive a register listing each item, its location, its class, the test results and the recommended retest date. Failed items are labelled clearly and taken out of use. Where it's a simple fix, such as a replacement plug, a correct fuse or a new IEC lead, we can usually do it on the spot.
