Portable Appliance Testing (PAT) is the term used to describe the examination of portable or moveable electrical equipment to ensure its safe use.
As a student, tenant, contractor or member of staff, you need to be aware of what to do in relation to PAT and the electrical equipment you are responsible for.
PAT covers everyday items such as kettles, computer hardware and extension leads, as well as equipment used in laboratories, theatres and catering and hospitality establishments.
A portable or movable appliance is any electrical equipment that is capable of being moved whilst either connected or disconnected from an electrical supply. In general it will have a lead (cable) and a plug, but includes fixed equipment that is connected via fused connection. It includes:
There are three different types of PAT with simple visual checks and combined PAT being the most common.
These are checks made by the person using the electrical equipment to ensure there are no immediately visible signs of damage before it is connected to the mains supply or to check for any obvious faults, such as cracked casing or exposed wires. This helps to ensure that damaged or faulty equipment is recognised and can be removed from use without delay so that it can be either be repaired by a competent, authorised person or responsibly disposed of.
Simple visual checks should be made when equipment is moved, installed or as part of an annual health and safety inspection, but could be done at any time by the user of or the person responsible for the equipment.
See our guide to carrying out simple visual checks (.pdf) on electrical equipment for more information.
Typically a formal visual inspection only applies if equipment becomes faulty or is being used in higher risk areas (.pdf), such as laboratories, workshops or theatres, where there may be specific local rules on when electrical equipment requires formal visual inspection by an authorised PAT tester. The person responsible for the area will arrange formal visual inspections, if these are required.
A formal visual inspection involves (in addition to the simple visual check) disconnecting the equipment from the electrical supply, removing the plug cover or equipment casing cover to check that the internal parts of the plug and cable are properly connected, secure and have the correct fuse with the correct rating fitted and there is no sign of internal damage, overheating or entry of liquid, dust or dirt.
Some faults cannot be detected by simple visual checks or formal visual inspections, such as a broken earth wire within a flexible cable or the inside surfaces have been contaminated. Combined PAT involves removing the outer casing to check for correct fusing, correct polarity of supply cables, effective termination of cables and core wiring, and that the equipment is suitable in the environment where it is to be used. A testing unit is used to detect any faults that cannot be identified visually.
Combined PAT should be carried out in the following circumstances: