This guiding principle is intended for those who have control over or use portable electrical equipment.
Portable electrical equipment could cause an electric shock or burn, or fire due to damage, wear or misuse.
This guidance covers portable equipment that is connected to the fixed mains supply or to a locally generated supply, for example a local diesel generator. The safety of portable electrical equipment depends on the continued integrity of the earthing, and correct connections of the fixed electrical installation (this includes the wiring, fuse box/consumer unit, and switches up to and including the socket supplying the equipment). You should also correctly select, use and maintain the fixed installation; although this is outside the scope of this guidance.
The maintenance plan described in this guidance is based on a straightforward, inexpensive system of user checks, formal visual inspection and testing. User checks and formal visual inspections can be carried out by a competent employee. In this context ‘competent’ means having suitable training, skills and knowledge for the task to prevent injury to themselves or others. This guidance also makes it clear when testing is needed. When testing is necessary, a greater degree of competence will be required.
Portable electrical equipment should only be used in accordance with the manufacturer’s instructions, for its intended purpose, and in the environment it was designed and constructed for.
CONTROLLING THE RISK
Failure to maintain equipment is a major cause of electrical accidents involving portable equipment. The likelihood of accidents occurring and their severity will vary depending on the type of electrical equipment, the way in which it is used and the environment it is used in.
Control of risks arising from the use of portable electrical equipment should be based on a risk assessment. A risk assessment is about identifying hazards and taking sensible and proportionate measures to control the risks in the workplace. Risks can be managed and controlled by setting up an appropriate maintenance plan including the measures referred to in this guidance.
PORTABLE EQUIPMENT AND CABLES
Portable equipment and the electrical connections to it (eg the plug and flexible cable and its terminations) are likely to be subjected to, and more vulnerable to, physical damage and wear or harsh treatment in use than equipment which forms part of the fixed installation. The fixed installation is usually provided with a significant degree of protection against damage by the fabric of the building or fixed enclosure.
The risk of receiving an electric shock will be greater when the user of portable electrical equipment is standing on a surface that is a good electrical conductor (such as a wet floor, the ground outside, a concrete floor or on scaffolding) than if they are standing on a wooden floor and not in contact with earthed metalwork.
The most vulnerable item of any portable equipment is often the cable (sometimes called cord, lead or flex) that supplies the equipment. The cable may deteriorate due to ageing or environmental effects, abuse or misuse, fail because of repeated flexing, or suffer mechanical damage. The most obvious examples of mechanical damage are being struck or penetrated by objects.
The cable should be replaced before a dangerous fault develops, such as exposure of conductors, or possibly arcing between broken conductor ends.
Some portable equipment (such as saws, grinding machine and welding machines) is capable of causing damage to the sheath, or even to the insulation of its own cable. The cable should be secured in such a way that it does not come into contact with parts that are moving or hot. The users of such equipment should always be alert to avoid such damage. If damage does occur they should stop using the equipment and report it to their manager.
Although a good initial level of safety can be achieved by correct selection and use of equipment and its connectors and cables, lasting safety can only be attained by ongoing and effective maintenance.
The maintenance plan should be designed to be proactive, ie planned to prevent incidents arising, rather than reactive, where action is taken following an incident or accident. The action taken should be appropriate to the risk, e.g. the frequency of inspections and any necessary testing will depend on the type of equipment in use, how it is used, how often, and where it is being used.
Effective maintenance of portable electric equipment can be achieved by a combination of:
- Checks by the user.
- Formal visual inspections by a competent person.
- Where necessary a combined inspection and test, also known as a portable appliance test (PAT), by an electrically competent person.
The aim of these checks is to determine whether the equipment is fully serviceable or whether remedial action is necessary to make sure it is safe to use.
REPAIR AND REPLACEMENT
The repair of portable electrical equipment requires specialist knowledge and expertise if the faulty or damaged equipment is to be restored to the necessary safe condition.
Where flexible cables have been in use for a long time, it is better to replace rather than repair them because conductor wires, insulation and sheathing materials deteriorate.
For long lengths of cable with the damaged part close to one end, the damaged section can be cut off. If the damage is not near one end, after removing the damaged section, a join of the healthy sections can be made by using a proprietary cable coupler. If a coupler is used, the socket part must be on the section fed from the electricity supply side and the plug part should be on the cable connected to the equipment. Such repair work must be undertaken by a competent person. It may be easier to replace relatively short lengths of unsatisfactory cable rather than carrying out repairs.