There is no law that names 'PAT testing' directly, but the Electricity at Work Regulations 1989 require every employer to maintain electrical equipment so it does not cause danger, so far as is reasonably practicable. The Health and Safety at Work etc. Act 1974 sits above this as the general duty of care on employers to keep staff and visitors safe. PAT testing (in-service inspection and testing to IET Code of Practice, currently 5th Edition) is simply the recognised, practical way of proving that duty has been met.
The 'duty holder' is normally the employer or person in control of the premises (e.g. landlord for rented equipment). They must ensure competent persons carry out testing - competence means the right training, knowledge and experience, not necessarily a specific qualification, though City & Guilds 2377 evidences it.
There are no legally fixed testing intervals. The HSE and IET Code of Practice both push a risk-based approach: frequency depends on the type of equipment, environment and usage (e.g. a construction site 110V tool needs checking far more often than an office desk lamp). The old 'every 12 months for everything' idea is a common myth and a common exam trap.
Portable Appliance Testing (PAT) applies to electrical equipment that is not fixed wiring. Under the IET Code of Practice (5th Edition) equipment is grouped by how it's connected and moved, because that dictates the risk and the test regime.
Expect questions asking you to identify the class from a symbol or description, match the correct test to the class, and categorise equipment by mobility. Know the double-square symbol for Class II and the SELV voltage limits for Class III cold.
The frequency of inspection and testing for electrical equipment is NOT fixed by law. The Electricity at Work Regulations 1989 simply says equipment must be maintained to prevent danger. HSE guidance and the IET Code of Practice for In-Service Inspection and Testing of Electrical Equipment give suggested initial intervals, which the duty holder then adjusts using risk assessment.
A competent person sets the interval based on:
There is no single correct number for all equipment. A candidate who quotes one interval for everything has misunderstood the syllabus.
User checks (before use) and formal visual inspections (by a trained person, no test equipment) both happen far more often than combined inspection and testing. Many faults are caught by these two steps alone, so testing intervals can often be longer than people assume.
Intervals are not fixed forever. If test records show a high fail rate, or the environment changes (equipment moved to a harsher location), the interval should be shortened. Conversely, a strong pass history over several test cycles can justify extending it.
Every piece of portable electrical equipment should get a quick user check before each use. This isn't a formal test, it's a simple visual look-over done by the person using the equipment, not a competent person or PAT technician. No paperwork or recording is normally required, though some organisations do log it.
If anything looks wrong, the equipment must be taken out of use immediately, labelled, and reported. Never used and hope for the best.
This is a step up from the user check. It's carried out by a competent person, more thorough, and it IS recorded, usually with a pass or fail entered on a register or asset log. It covers everything the user check does, plus opening the plug if it's not a moulded-on type.
Guidance (IET Code of Practice) gives suggested intervals depending on equipment risk and environment, but there is no fixed legal frequency. A formal visual inspection is done before an electrical test, and a good proportion of equipment (most failures, around 90-95%) are caught by visual inspection alone, without any instrument test at all. This is why visual inspection is the single most important part of the whole PAT process.
Combined inspection and testing is the standard PAT procedure: every appliance gets a formal visual (and where relevant instrumental) inspection FIRST, then electrical tests are carried out. Inspection catches most faults, testing confirms what inspection cannot see.
Around 90-95% of faults found during PAT are picked up by visual inspection alone - damaged cable, cracked casing, wrong fuse rating, missing cord grip, signs of overheating. Testing without inspecting first is bad practice: you might electrically test a unit with a visibly split plug top and miss the obvious danger, or the fault could make the instrument test meaningless.
A combined result is only a PASS if BOTH the inspection and every required test are satisfactory. If inspection fails, the item should be failed and taken out of use - you do not need to proceed to testing a visibly dangerous item, though many competent persons will still test to gather full fault data before repair.
Portable Appliance Testing isn't just poking a probe into a socket - it's a legal and safety paper trail. Under the Health and Safety at Work Act 1974, the Electricity at Work Regulations 1989, and PUWER, employers must show 'suitable and sufficient maintenance' of electrical equipment. HSE guidance (INDG236, HSG107) and the IET Code of Practice for In-Service Inspection and Testing of Electrical Equipment (5th Edition) set the accepted best practice, but they are NOT law themselves - they're the evidence you'd point to in court.