Portable appliance testing (PAT) overview
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.
Definition of portable or movable appliances
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:
- Items that can easily be moved around, eg: vacuum cleaners, kettles, fans, mains powered laptops, temporary lighting, electrical hand tools, stage lighting
- Larger items that could be moved (but only rarely), eg: photocopiers, printers, PCs, microwaves, vending machines, electric cookers, fixed lighting and sound rigs
- Hand-held items that do not have a plug but have been wired in or are fixed, eg: such hair dryers changing room
- Mobile phone and other battery-charging equipment that is plugged into the mains but not the phones themselves / battery-operated equipment
- Extension leads, multi-way adaptors and connection leads
- Portable residual current device (RCD) is fitted to electrical equipment
Items not considered a portable or movable appliance
- fixed 'built-in' white goods, such as fridges or freezers (these are covered under the appropriate cycle for fixed installation testing)
- charging equipment for battery operated equipment, such as mobile phones or iPads, which have a transformer or USB port as part of the plug. However, if there is a mains lead between the plug and transformer, the mains lead would be considered portable electrical equipment
- USB operated equipment, such as a mobile phone charger, or that which is powered by connection to a computer USB port, such as mobile phones used as hard drives, or small fans
- electrical equipment which is wired into the mains supply but is not designed to be moved or which is part of a fixed installation, ie the equipment remains in the place where it is installed. Examples include water boilers, wall-mounted hand dryers and fixed water dispensers. This type of equipment should be dealt with in accordance with the maintenance cycle for fixed installations
What PAT involves
There are three different types of PAT with simple visual checks and combined PAT being the most common.
Simple visual checks
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.
Formal visual inspection
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.
Formal visual inspection with formal electrical testing (known as 'combined PAT')
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:
- if the equipment is considered to be faulty but simple visual checks or formal visual inspection cannot identify the problem
- after any repair or modification to electrical equipment
- at appropriate frequencies depending on:
- the type of equipment and whether it is hand-held or not
- manufacturers' recommendations
- the initial integrity and soundness of the equipment
- the age of the equipment
- the working environment in which the equipment is used, eg wet, dusty or flammable areas
- where there is a greater likelihood of mechanical damage, such as cables being wrongly used to carry the weight of the equipment
- the frequency of use
- if there is foreseeable misuse of the equipment where analysis of previous records of maintenance, such as formal visual inspection and combined PAT, highlight any trends which indicate a higher frequency of testing may be required
Forms and resources
- Inventory of portable and movable electrical equipment (.doc)
- Inventory of portable and movable electrical equipment (.xlsx)
- Record of testing carried out (.doc)
- Record of testing carried out (.xls)
- PAT for low risk environments (including frequencies) (.pdf)
- PAT for higher risk environments or activities (includes frequencies and competency requirements of testers) (.pdf)
