Electricity is a familiar and necessary part of everyday life, but it can kill or severely injure people and cause damage to property.
There are some simple precautions when using eclectically powered equipment that can be taken that will significantly reduce the risk of electrical injury to you and others around you:
Perform a risk assessment to identify the hazards, the risks arising from those hazards, and the control measures you should use.
Check that the electrical equipment is suitable for the work and way in which it is going to be used.
Check that the electrical equipment is in good condition. The HSE booklet ‘Maintaining portable and transportable electrical equipment’ will help you do this.
Check that the equipment is suitable for the electrical supply with which it is going to be used, and the electrical supply is safe.
It is often beneficial to use a Residual Current Device (RCD) between the electrical supply and the equipment.
Make sure that the user of the equipment is trained to use it safely and can keep others safe.
Make sure the user knows which personal protective equipment to wear, how to use it, and make sure they do.
Check that the electrical equipment is suitable
The equipment should be physically capable of doing the job, and designed and constructed so that mechanical and electrical stresses do not cause the equipment to become unsafe.
If the environment is damp you may choose to use battery or air powered equipment, or equipment that operates at a reduced voltage such as that supplied by a transformer with an output that is centre tapped to earth (this halves the voltage between a live wire and earth). These are used in the construction industry and are readily available from hire shops.
If the environment is conductive with restricted movement (eg inside a metal tank) additional precautions are necessary. BS7671 'Requirements for Electrical Installations', IEE Wiring Regulations, Seventeenth edition, Section 706, gives guidance on this.
If there is the chance that there is an explosive atmosphere (containing flammable aerosols, vapours, gases or dusts) nearby you should ensure the work can be carried out safely and that the right equipment is chosen.
Check that the electrical equipment is in good condition
Many faults with work equipment can be found during a simple visual inspection:
Switch off and unplug the equipment before you start any checks.
Check that the plug is correctly wired (but only if you are competent to do so).
Ensure the fuse is correctly rated by checking the equipment rating plate or instruction book.
Check that the plug is not damaged and that the cable is properly secured with no internal wires visible.
Check the electrical cable is not damaged and has not been repaired with insulating tape or an unsuitable connector. Damaged cable should be replaced with a new cable by a competent person.
Check that the outer cover of the equipment is not damaged in a way that will give rise to electrical or mechanical hazards.
Check for burn marks or staining that suggests the equipment is overheating.
Position any trailing wires so that they are not a trip hazard and are less likely to get damaged.
If you are concerned about the safety of the equipment you should stop it from being used and ask a competent person to undertake a more thorough check.
Additional information on the visual inspection of electrical equipment is in the free guidance note Homeworking.
Additional regular inspections may be required where a risk assessment indicates this is necessary (such as where equipment is used in a harsh environment). These inspections should be performed by a competent person using suitable equipment, and often enough to ensure equipment does not become unsafe between the inspections.
The table below gives a list of suggested initial inspection intervals for different types of equipment. The combined inspection and test could be a Portable Appliance Test (PAT), or a detailed test with a more sophisticated instrument. You should make sure that the person carrying out the tests is trained and competent to do so. See the guidance booklet Maintaining portable and transportable electrical equipment for more information.
Check that the electrical equipment is suitable for the electrical supply
Make sure that the electrical equipment you are intending to use is suitable for the electrical supply to which you are connecting it. Check the voltage is correct and that the supply can deliver the current required by the equipment (the power requirements of the equipment will be shown on its rating plate).
Check the electrical supply is safe to use
You should be sure that the electrical supply is safe to use. Regular tests performed by a competent person, using suitable equipment are a good way of reducing risks. Where there is evidence that the supply may not be safe, such as damaged equipment or wiring, the supply should not be used until work has been done to correct this. Some simple user checks can be carried out on electrical socket outlets using an electrical socket tester, but it is essential that the correct type of tester is used (PDF). If any doubt remains regarding the safety of the electrical supply, a competent person should be consulted.
Use a Residual Current Device (RCD)
A Residual Current Device (RCD) can reduce the likelihood of an electrical injury but a shock can still cause very serious or fatal injuries, so an RCD should only be used as a secondary means of reducing the risk of people being injured by electricity. RCD’s are not designed to prevent the ignition of an explosive atmosphere and should not be used for this purpose.
The best place for an RCD is built into the main switchboard, as this means that the electrical supply is permanently protected. If this is not possible, an electrical socket outlet incorporating an RCD, or a plug in RCD adaptor, can also provide additional safety.
If an electrical socket outlet incorporating an RCD, or a plug in RCD adaptor is used it should be tested, by the user, prior to use by operating the Test button. Faulty RCDs should not be used and either removed for use or labelled as faulty.
An RCD detects some, but not all, faults in the electrical system and rapidly switches off the supply, reducing the potential for injury caused by a common type of electric shock. To reduce the likelihood of injury to people the RCD should have a tripping current of not more than 30 milliamps (mA). RCDs with a higher tripping current are used to protect against fire.
Remember:
An RCD is a valuable safety device, never bypass it; if the RCD trips, it is a sign there is a fault. Check the system before using it again; if the RCD trips frequently and no fault can be found in the system, consult the manufacturer of the RCD; the RCD has a test button to check that its mechanism is free and functioning. Use this regularly.
If lighting circuits are protected by the same RCD that also protects other equipment, a fault that causes the RCD to trip will also result in the loss of lighting that could give rise to a number of risks (such as trips and falls or the dangers from moving machinery). You should perform a risk assessment to identify the effect of fitting an RCD to electrical circuits.
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