PAT Testing for Worker Safety
Testing Portable Electrical Equipment
According to the Health and Safety Executive (HSE) around a quarter of all electrical accidents reported at work involve portable electrical equipment, with five each year resulting in death.
Tragically, the majority of these incidents could have been avoided with some very simple maintenance.
It is the employer’s responsibility to ensure electrical safety, and accidents caused by their failure to do so can result in prosecution under the Electricity at Work Regulations 1998, which state:
As may be necessary to prevent danger, all systems shall be maintained so as to prevent so far as reasonably practicable, such danger.
Electricity at Work Regulations 1998
The legislation relates to any equipment which connects to single–phase electrical mains supplies by a flexible cable and a 13 Amp plug, or which plugs into an adaptor supplied from a 13 Amp plug. Extension leads and adaptors are also included, and must be inspected and tested.
Portable Application Testing (PAT) ensures electrical safety by regularly checking for faults and correcting before they can cause an accident.
Most appliances fall into two categories — Class I or Class II, and each requires different tests.
- Class I PAT Testing
- This kind of equipment uses basic insulation of electrical parts and enables connection of metal parts that (in the event of insulation failure) may become live to earth. Such equipment has 3 wires — live, neutral and earth. PAT tests check the integrity of the earth connection to verify that the resistance is low enough to remove dangerous voltage. It also ensures the maintenance of higher than minimum levels of insulation.
- Class II PAT Testing
- Class II equipment does not reply on the earth protection, it provides double or reinforced insulation and usually comes with a mains cable with a live and neutral conductor, or in some cases, with three conductors. PAT testing ensures that the double insulation is of high enough quality to reach the required minimum levels.
The correct steps for PAT Testing are:
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User Check
Equipment should be checked by the user before use, as signs of damage, overheating, misuse are easy to spot.
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Visual Inspection
This should be carried out by someone trained to do thorough checks, for example of plugs, frayed leads, fuses, mains cable or casings.
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Combined Inspection and Testing
This is required for faults which are not obvious and may be internal, and caused by misuse or wear and tear. Such faults can be identified by a PAT tester. For low risk applications a member of staff with relevant training can do this with a standard PAT tester. In higher risk situations more complicated tests must be carried out by a skilled specialist.
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Whoever is carrying out the PAT test must:
- Test Earth Bond on Class I appliances, ensuring ALL earthed paths on appliances are checked
- Check insulation resistance
- Remember to switch the appliance on so that the tester can check for escaping voltage
- Check that the fuse is conducting
- NOT touch the appliance in case of insulation failure
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How often must tests be carried out?
There is no set time period for PAT testing — it depends upon the application and factors such as whether it is in a harsh environment or a low risk area.
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Keeping records
Again, there is no set rule regarding documenting the condition of electrical equipment, however keeping records of maintenance and test results will ensure that the information on the state of equipment is up to date and can be monitored ? which will in turn ensure electrical safety for staff. It will also provide evidence that the employer has taken all reasonable steps to comply with the Electricity at Work Regulations, should a claim be made against them by a worker injured through use of a portable appliance.
For further information, and details of the Code of Practice for In–service Inspection and Testing of Electrical Equipment, visit:
- Maintaining portable electrical equipment in offices and other low–risk environments (PDF: 48.0 KB)
- IEE Wiring Regulations webpages
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