Electrical Safety at Work - PAT testing and Preventative Maintenance
3rd November 2009
ELECTRICAL SAFETY AT WORK - THE ROLE OF PAT TESTING AND PREVENTATIVE MAINTENANCE
Jim Wallace of electrical safety specialist Seaward, explains the importance of ensuring the safety of portable electrical equipment used in the workplace.
With the HSE reporting around 1,000 workplace electrical accidents and 30 deaths each year, reducing the dangers associated with the use of unsafe electrical appliances in the workplace is of vital importance.
Fires started by poor electrical installations and faulty appliances also cause many more deaths and injuries - and considerable disruption to business activities.
Responsibility for the safe operation of equipment in the workplace rests firmly with the employer. Although the importance of portable appliance testing (PAT) in many industrial and construction environments is well understood, the same responsibility also applies to the range of electrical and electronic equipment used in the wider commercial environment. The Health & Safety At Work Act 1974 puts a duty of care upon both employer and employee to ensure the safety of all persons using the work premises, but the particular legal requirements relating to the use and maintenance of electrical equipment are contained in the Electricity at Work Regulations 1989 (EAWR).
Regulation 4(2) of the EAWR specifically requires that all electrical systems be maintained, so far as reasonably practical, to prevent danger. This requirement covers all items of electrical equipment including fixed, portable and transportable equipment - essentially anything connected to a building´s electrical system with a plug or cable. Since the introduction of the EAWR, the EC Provision of and Use of Work Equipment Regulations 1992 (PUWER) also places general duties on employers and lists minimum requirements for work equipment to deal with selected hazards, whatever the industry.
The severity of an electric shock on an individual is dependent primarily upon the magnitude of the current, the path taken through the body and the length of time the current flows. However, the following guide to the effects of current on the human body is worthy of consideration:
0.9 - 1.2mA Current just perceptible
15.0 - 20.0mA Release impossible: cannot be tolerated over 15 minutes
50.0 - 100.0mA Ventricular fibrillation, leading directly to death
100.0 - 200.0mA Serious burns and muscular contraction of such a degree that the thoracic muscles constrict the heart
If we consider that direct contact with a 240V supply can result in a current of around 250mA flowing through the body, the lethal potential of a faulty electrical appliance is easily understood.
Electrical portable appliances are often roughly handled when moved from place to place, operate in a variety of environments and in many instances have more arduous and onerous usage compared to fixed equipment. As a result, at any time it is estimated that around 20% of electrical appliances used in workplaces could require re-testing to ensure that they do not pose a hazard to users.
For example, how can any gradual deterioration in the electrical integrity of an office-based vending machine, photocopier or kitchen appliance be identified or a potentially dangerous fault in a desk lamp, fan or item of office cleaning equipment be diagnosed? Evidence shows that a large number of the dangers, deaths and injuries caused by misused or faulty electrical equipment can be avoided if proper electrical checking procedures had been applied. The HSE recognises this fact and advises, "A simple visual inspection is likely to be sufficient for equipment used in a clean dry environment. In addition, equipment that is more likely to become damaged or is operated in a harsh environment is likely to require more demanding electrical tests.
"It is good practice to assess how often equipment being used for work purposes should be tested, write down your findings, make sure the testing is carried out, and write down the results of the tests."
While specialised business equipment such as computers, printers, kettles and fans do not present the same degree of risk as electric power tools, badly wired plugs and frayed leads could still give electric shocks to users and cause office fires. The emphasis on maintaining a safe working environment is therefore constant and some examples of the sort of horror stories uncovered by periodic inspection and test programmes illustrate this point perfectly.
For example, one public sector employer now insists that all faulty equipment must have the whole lead cut off as close to the appliance as possible. This is the result of an earlier situation when a caretaker rewired a plug onto an appliance that had previously had the plug removed after failing its regular test. The failed but reconnected appliance was then responsible for causing a fire causing thousands of pounds worth of damage.
In an engineering company, factory workers risked their lives by continually replacing a fuse that persistently failed in a power tool with a metal connector, rather than raise the issue and question why the fuse was always blowing. The temporary modification was uncovered during a periodic portable appliance test.
Even in offices, employees have been found to be taping up cracked power packs with adhesive tape rather than having them replaced. Elsewhere, in a school laboratory, a safety engineer had to take all the soldering irons out of service after the students had used them to burn through their own plugs. All of these dangerous situations would not have been detected without the presence of regular inspection and testing procedures.
Planned and proactive safety programmes must therefore be capable of detecting potential problems with electrical appliances before they occur and this is the role of preventative maintenance programmes. The majority of equipment defects can be found during formal visual inspection - the HSE says that 95% of faults or damage can be identified just by looking. For example, a detailed examination by a competent person is likely to eliminate hazards caused by cable or plug damage, faulty wiring or other obvious signs that the equipment´s condition could create faults or a danger to users.
The HSE booklet, Maintaining Portable and Portable Equipment, HSG 107, provides details on the sort of visual user checks and more formal visual inspections required. However, to identify all potentially dangerous faults, visual inspection needs to be linked with a programme of periodic inspection and testing that is capable of revealing any ‘invisible´ electrical faults such as earth continuity, insulation integrity, correct polarity, excessive protective conductor current and other potential problems.
Clearly such combined inspection and testing measures should be appropriate to the particular risk posed by the equipment and its environment. This means that maintenance procedures in offices might be required less frequently than in other high risk environments such as construction sites - but will still be needed to verify safe working conditions. For example, smaller offices or workplaces with only a few electrical appliances, and a staff of limited technical ability, might be regarded as relatively low risk environments. Here a responsible attitude might be regarded as a regular process of formal user checks and visual inspection, combined with some limited periodic testing. A different view, however, might need to be taken by a large organisation, with different departments and having many different types of electrical equipment used by staff. In this case, ensuring the safety of appliances may not only be a matter of ensuring the correct test equipment is available, but also having the ability to show that the right tests have been performed at the right time in the correct sequence - with records of test levels and results.
Overall frequency of inspection and testing of equipment will depend on whether the electrical items are Class I or Class II construction and the environment in which they are used. For example, an office kettle might require a visual inspection every six to 12 months and combined inspection and testing every one to two years. On a broader front, inspection and testing of some construction equipment and power tools might be advisable every 1-3 months, but this can range to up to 12 monthly intervals for some industrial locations, commercial kitchens and other workplaces, to 24 months and above for hotels, some offices and shops. Frequency of testing is therefore an important factor that requires proper consideration and risk assessment. Information is provided in the HSE Guidance Notes on Portable Appliance Testing and the updated IEE Code of Practice on In Service Electrical Safety Testing which both provide details of recommended test intervals for different types of equipment and different workplaces.
Competency to test
Cost effective maintenance of portable electrical equipment can therefore be achieved through a combination of user checks, formal visual inspection and electrical testing. Combined inspection and testing programmes require greater level of competence than for inspection alone. For example, the EAWR require that testing should be carried by a competent person who can correctly identify those items to be inspected and tested, which tests are appropriate, how to perform the tests and how to interpret the results.
Further clarification on the question of competency is also provided in the third edition of the IEE Code of Practice which advises that this person should possess sufficient technical knowledge or experience to be capable of ensuring that injury is prevented. The Code continues with further explanation on what that technical knowledge or experience may comprise, including such factors as having an adequate knowledge of electricity, an adequate understanding and practical experience of the system to be worked on and an understanding of the hazards that may arise and the precautions to be taken. Although people carrying out the testing of portable electrical equipment should be appropriately trained for this work, many field service organisations and contracting companies have set up specialist portable appliance testing operations.
Other organisations have responded with the introduction of in-house testing protocols managed by maintenance managers, safety engineers, site electricians or facilities management personnel. To demonstrate PAT competency, the City and Guilds 2377 qualification is designed to provide the skills and knowledge required for the planning and implementation of a testing programme for portable electrical appliances.
Divided into two parts, City and Guilds 2377-100 Management of Electrical Equipment Maintenance is for those who are responsible for the safety and maintenance of a building or site and who may buy-in a PAT testing service. City and Guilds 2377 - 200 Inspection and Testing of Electrical Equipment is designed for those actually carrying out the portable appliance testing. City & Guilds 2377 is usually delivered at one or two day courses and is available through electrical trade organisations, local colleges and private training providers. In addition, comprehensive training courses on portable appliance testing are also provided by the test equipment manufacturers, trade bodies, wholesalers and training companies. As well as providing details of the relevant H&S legislation, electrical fundamentals, typical faults and dangers associated with different types of electrical appliances, these courses also include practical experience of using test equipment.
Electrical Test equipment
To help business owners, in-house safety personnel and specialist PAT contractors meet their PAT obligations, a range of portable appliance testers are available that make the safety testing process safe, fast and easy to carry out.
Test instruments are available which start with the relatively simple to operate pass/fail checkers for basic safety checks on equipment and which generally provide an immediate ‘go/no go´ display. These are designed for use by those who may be relatively unskilled in electrical work and the test results do not require any interpretation by the user.
However, for more comprehensive test requirements, sophisticated microprocessor controlled testers are available that combine user-friendly operation with a whole range of other features for particular test demands or routines.
Lightweight testers are now available that incorporate all Class I and Class II required electrical safety tests in a compact hand held instrument. Long life battery power eliminates the reliance on mains outlets for testing, making the instrument totally portable and suitable for universal testing applications - particularly in large buildings or within large organisations.
The incorporation of Bluetooth technology in some testers allows the wireless connection of bar code scanners, safety label printers and other accessories - allowing totally cable-free testing, without the cumbersome and constant plugging in and unplugging of leads and cords. As well as recording the electrical test results in an internal memory for subsequent downloading, the latest generation PAT testers also have the facility to record the results of other safety management data including emergency safety lighting conditions, or the condition of fire extinguishers, for example, as part of more comprehensive workplace safety audits. Advanced testers can also be linked directly safety-labelling printers for the fast and automatic production of appliance test labels on-site. The labels can not only provide confirmation that the equipment is safe to use but often include details of ‘next test´ due dates.
Labelling an appliance after PAT testing is good practice to provide a clear indication to the user that it has been safety tested and when the retest is due. The label alone however does not provide details of what tests have been performed or the safety margin between measured results and the allowable limits. Maintaining a record system also makes it much easier to demonstrate compliance with the EAWR if the electrical safety of an appliance is ever brought into question.
Although there is no formal requirement in the EAWR for records, the HSE Memorandum of Guidance on the Electricity at Work Regulations HSR25 advises that records of tests should be kept throughout the working life of equipment as a means of reviewing schemes and demonstrating that safety policies have been enforced.
For example, in any proceedings for an offence in contravention of the EAWR, the most effective method is for the dutyholder to prove that ‘all due diligence´ has been exercised and that appropriate measures have been taken to prevent accidents. Powerful PAT database programs have become simpler and faster to use by combining Windows features such as icons to represent sites, locations and different appliances, using drag and drop mouse actions to replicate location changes. The use of computerised portable appliance testers also enables data to be transferred directly from the instrument to a PC-stored database allowing an automatic update of test records, the generation of test reports and advance testing schedules.
For testers that do not possess an internal results memory, PDA based test record keeping software programs are also under development - enabling test records to be updated manually while testing takes place, for transfer to main PC-based systems at the end of a shift or test programme. These record keeping and test management programmes can also utilise new e-scheduler facilities that work alongside results databases to continually monitor and interrogate the stored test records. This software automatically looks for a trigger condition (test date) generated by any appliances requiring re-test to automatically highlight those appliances becoming overdue for test, maintaining safety and ensuring that equipment is always tested in line with safety procedures.
With growing awareness of the importance of the safety of electrical appliances, many private and public sector organisations have come to recognise the importance of regular inspection, test and maintenance of all electrical equipment used in the workplace.
IN SERVICE ELECTRICAL SAFETY TESTING CHECKLIST
- Establish an electrical tool, equipment and appliance register, preferably using a safety testing software program
- Carry out regular visual inspections
- Nominate a ´dutyholder´ with responsibility for the safety of electrical equipment - ensure ‘dutyholder´ is fully trained
- Commit to regular inspection and test program and determine the frequency of testing in consultation with HSE guidelines
- Ensure tests are carried out in keeping with the frequency of testing plan
- Establish a formal record keeping system, file or software
- Determine a re-test schedule well in advance