Portable appliance testing
Health and safety regulations require that electrical appliances are safe and well maintained to prevent harm to workers.
[3] Domestic premises are not covered by this legislation, although occupiers' liability requires householders not to deliberately expose occupants or visitors to unreasonable risks.
Guidance from the IET (published under the IEE brand) and the Health and Safety Executive (HSE) recommends that a competent person must inspect the installation regularly in any public building or a place that people work.
They suggest initial intervals for combined inspection and testing that range from three months (for construction equipment) to one year, and in many cases, longer periods for re-testing (certain types of appliance in schools, hotels, offices and shops).
Today a great many private companies and other organizations do meet their legal obligations to protect their workers by an enforced PAT regime, but it is not the only route.
HSE publications have relaxed their tone somewhat to acknowledge this, and now point out that in many situations an annual PAT test is disproportionate to the risks and is often not required.
Thinking about the type of equipment in use, and how it was used, the HSE looked back at the results from its annual testing of portable appliances across its estate over the last five years.
Also, they decided to continue to monitor any faults reported as a result of user checks and visual inspections and review its maintenance system if evidence suggests that it needs revising.
Electrical equipment will continue to be maintained by a series of user checks and visual inspections by staff that have had some training.
Regular user checks and visual inspections can be a good method of maintaining portable electric equipment.
[6] In the UK there is no legal instrument that requires a sub-contractor to ensure that all tools and equipment are PAT inspected before bringing onto a site of work.
The internal policies of many UK businesses and educational establishments make mistaken reference to PAT inspection being a legal requirement under the Electricity at Work Regulations, which is false.
The HSE recommend policies use phrases such as "equipment that is brought onto site for an event must be in a safe condition" and refrain from overzealous statements such as "must be PAT inspected" which can be restrictive without improving safety.
[citation needed] In some cases testing was conducted on a three-month (high-risk) and six-month (low-risk) cycle from the early 1960s onwards.
Extensive record-keeping was made into log-books and generally the equipment used was an insulation resistance tester, simple hand tools and visual inspection.
Values should not be less than 1MΩ for Class I and Class II appliances at 500 V d.c., or at 250 V d.c.[9] to avoid the equipment apparently failing the test because the metal oxide varistors (MOVs) or electro-magnetic interference (EMI) suppression triggered, for equipment containing voltage limiting devices such as MOVs or EMI suppression.
A deficiency of the insulation resistance test is that the DC voltage will not activate electromagnetic switches or internal relays etc.
This is usually a hand-held device with a sensing antenna that can be scanned over the areas where the door meets the casing to find any radiation hot-spots whilst the unit is operating.
It has become accepted practice however for individuals operating as PAT Testers to hold a nationally recognised City & Guilds 2377–22 qualification (or a later version such as 2377-77 Level 3 Award in the In-service Inspection and Testing of Electrical Equipment (603/6790/8)).
[14] Guidance is provided by the IET in the form of the Code of Practice for In-service Inspection and Testing of Electrical Equipment – 5th Edition published in October 2021.
Advanced PAT testers can be effective as facility management tools because they may record the location and test status of electrical equipment and appliances.
