There is no legal interval, so the honest answer is that frequency follows risk. A hand-held drill on a building site, a kettle in a quiet office and a server in a locked room do not need the same attention, and treating them alike either wastes money or misses the equipment most likely to hurt somebody. HSE guidance sets out suggested intervals rather than rules, and expects the duty-holder to justify their own.
PAT testing frequency: how often is PAT testing required?
Four things. The type of equipment and whether it is class I or class II. The environment, because damp, dust, heat and vehicles all shorten a flex's life. How the equipment is used and moved, since portable and hand-held equipment fails far more than a fixed appliance. And the history of the equipment, because a type that keeps failing is telling you something.
The three levels of check, and what each adds to the PAT test cost
User checks before use, which cost nothing and catch most damage. Formal visual inspections by somebody trained, at intervals. And combined inspection and test with an instrument, least often of the three. Guidance builds a regime out of all three rather than relying on the annual visit that people mean when they say PAT testing.
Suggested intervals, and what they are not
HSE guidance offers suggested initial intervals by equipment type and environment, from months for hand-held equipment in harsh conditions to years for stationary equipment in an office. They are starting points to be reviewed against your own failure record, not a schedule the law hands down, and a regime that never changes has not been reviewed.
How long does PAT testing last?
Until the equipment is damaged, which can be the same afternoon. A label with a date on it says when the item was last inspected, not that it is safe now. That is the argument for user checks between formal inspections and against reading the label as a guarantee.
How long does PAT testing take on the day?
A tester works through items at a steady rate once set up, so the visit length follows the item count more than anything else. Preparation is what changes it: equipment gathered in one place, access to sockets, and somebody who can say what is used where. A site walked in advance is tested faster on the day.
How often does pat testing need to be done, by the three layers
The question has three answers because there are three different activities, and conflating them is what makes every published figure look contradictory. The user check happens before use, every time, by whoever picks the item up, and needs nothing but instruction on what to look for: damage to the lead, the plug and the casing, and anything that has been used in a way it should not be. The formal visual inspection is periodic, done by somebody trained, and it is the layer that finds most real faults: wrong fuses, taped joints, strain on the cord grip, the wrong equipment for the environment. The combined inspection and test is the instrumented one and the only layer that finds a broken earth inside a lead. So how often depends on which layer is being asked about, and a programme that runs the third layer annually while skipping the first is spending money in the wrong place.
How often pat testing recurs once the register is split by area
The single change that makes a programme both cheaper and better is splitting the register by AREA rather than running one interval across a site. A school's IT suite and its design technology workshop have nothing in common; a hotel's bedrooms and its laundry have nothing in common; an office with a small workshop at the back has two regimes and usually runs the office one over both. Once the register is split, each area gets the interval its own equipment and environment justify, which lengthens the intervals in the low risk areas that hold most of the items and shortens them where the risk actually is. It also makes the decision defensible, because the reason is written against each area rather than being one number applied to everything.
Other questions people ask
How often should PAT testing be done by law?
The law sets no interval. The duty is to maintain equipment so as to prevent danger, and the frequency is for the duty-holder to justify from the risk.
Is annual PAT testing sensible for an office?
Often not. HSE guidance suggests longer intervals for stationary equipment in low-risk environments, with user checks and formal visual inspections in between.
How long does a PAT test last before it needs doing again?
There is no validity period. The label records when the item was last inspected, and damage after that date is what user checks are for.
How long does a PAT test take?
Each item takes a minute or two once the tester is set up, so the visit follows the item count. Gathering equipment beforehand shortens it noticeably.
How often should PAT testing be done UK wide, and who sets the interval?
Nobody sets it in law. The regulations require maintenance sufficient to prevent danger and leave the interval to the duty holder, informed by the equipment, the environment and the history. Industry guidance publishes suggested starting intervals by equipment class and premises type, and those are a starting point to be adjusted by what the register shows: a class of item that keeps failing earns a shorter interval, and a class that never fails in a dry office earns a longer one. An interval that has never moved in five years is a sign nobody is reading the results.