Pages in this chapter (9 of 9)
Portable appliance testing (PAT)
The checks and inspections above should reveal most potentially dangerous faults. Some faults, however, cannot be detected by looking alone. Examples are loss of earth integrity, such as a broken earth wire inside a flexible cable, deterioration of insulation, and contamination of internal and external surfaces. These can be reliably detected only by a combined visual inspection and test. This should be carried out periodically to back up the checks and inspections, and is likely to be justified:
- whenever there is reason to suppose the equipment may be defective and this cannot be confirmed by visual examination
- after any repair, modification or similar work
- at periods suited to the equipment, to how and how often it is used and to its environment
The inspection carried out with testing should usually include checking:
- the correct polarity of supply cables
- the correct fusing
- effective termination of cables and cores
- that the equipment is suitable for its environment
| Portable appliance testing: advantages | Portable appliance testing: limitations |
|---|---|
| Supports an appropriate maintenance system | A PAT label alone does not prove legal compliance or safe use |
| Can provide useful recorded evidence of tests performed | Describes condition only within the test scope at that time, not a guarantee of safety |
| Detects faults that cannot be seen | Items may be missed and so remain untested |
| Can identify faults and inform repair or withdrawal decisions | The competent tester must select methods suitable for the equipment, including sensitive IT equipment; computers are not automatically excluded |
| Trends or patterns of failure may be spotted |
Maintenance and test records
A record or label of each equipment inspection is a useful management tool for monitoring and reviewing how effective the maintenance scheme is and for showing that a scheme exists. It can also serve as an inventory of equipment and a check on the use of unauthorised equipment. The following records are generally set up and kept:
- a register of all equipment
- a record of formal and combined visual examinations and electrical tests
- a register of all faulty equipment
- a repair register
The log can include faults found during inspection, which may indicate places of use, or types of equipment, that suffer a higher than average level of wear or damage. This helps to check whether suitable equipment has been selected. Entries in a test log can also highlight any adverse trends in test readings that may affect the safety of the equipment, so that remedial action can be taken.
Frequency of inspection and testing
Deciding how often to inspect and test is a matter of judgement and should be based on an assessment of risk. A balanced approach should be taken, based on:
- what the equipment is
- its age
- its construction class
- how often it is used
- how long it is used for
- how often it is moved
- historical evidence on the suitability and safety of the equipment
- where it is used, meaning its environment
- what tasks it is used for
Further Reading
- Avoiding danger from overhead power lines, guidance note GS6, fourth edition, HSE
- Directive 2006/95/EC on electrical equipment
- Directive 2009/104/EC on the use of work equipment
- Electricity at work: safe working practices (HSG85), second edition, 2007
- Maintaining portable and transportable electrical equipment (HSG107), second edition, 2004
- Maintaining portable electric equipment in low-risk environments (INDG236)
- Safety in electrical testing at work (INDG354)
- The health and safety toolbox: how to control risks at work (HSG268)
- Working safely near overhead electricity power lines, HSE agriculture information sheet no. 8
Summary notes for Element 11 · Cheat sheet · Glossary. A study aid, not published or endorsed by NEBOSH.