Electricity kills and injures people. Normal mains voltage can kill. The Health & Safety Executive (HSE) reports around 1,000 electrical accidents at work every year, with about 25 people dying of their injuries. You can reduce these risks in your organisation by following some simple precautions.
The risk of injury from electricity is strongly linked to where and how it's used. Some equipment involves greater risk. Extension leads are easily damaged, as are other flexible leads, particularly where equipment is moved a lot. The risks are greatest in harsh conditions:
- in wet conditions, unsuitable equipment can become live
- outside, equipment may get wet and be at greater risk of damage
- in cramped spaces with a lot of earthed metalwork (such as inside a tank or bin), if an electrical fault developed it could be very difficult to avoid a shock
What are the hazards?
The main hazards are:
- contact with live parts causing shock and burns
- faults which could cause fires
- fire or explosion in a flammable or explosive atmosphere, like a spray paint booth
Provide safe and suitable equipment
- choose equipment that's suitable for the working environment: you might want to consider air, hydraulic or hand-powered tools in harsh conditions
- provide a clearly identified emergency cut-off switch near each fixed machine
- use nearby power sockets for portable equipment so it can be easily disconnected in an emergency
- ensure flexible cables always have the outer sheath of the cable firmly clamped into their plugs to stop the wires pulling out
- use proper connectors or cable couplers to join lengths of cable, not strip connector blocks covered in insulating tape
- replace damaged sections of cable completely
- make sure double-insulated equipment (often marked with a 'double-square' symbol) is properly connected
- protect light bulbs and other easily damaged equipment, as there's a risk of electric shock
- ensure that equipment used in flammable or explosive atmospheres is designed not to cause ignition (you may need specialist advice)
Make sure your electrical wiring and equipment are safe
You can control most of the risks for electrical equipment used in a clean dry environment with a simple visual inspection, backed up by testing as necessary. If you're worried about any equipment, stop it from being used and ask a competent person to check it. Equipment users should report any damage or defects they find.
- switch off and unplug the equipment before you start
- check that the plug isn't damaged and the cable is properly secured with no internal wires visible
- check the cable isn't damaged and has no repairs with insulating tape or an unsuitable connector
- if you find damaged cable , get a competent person to replaced it
- check that the outer cover of the equipment isn't damaged, burnt or discoloured
- move any trailing wires so they don't trip people up and are less likely to get damaged
- get a competent person to check the plug is correctly wired
- ensure the fuse is correctly rated by checking the equipment rating plate or instruction book
Equipment that's more likely to get damaged or that's used in a harsh environment will need more demanding tests. Get it inspected and tested by the manufacturer or an authorised service and repair agent. If not, a reputable servicing company that deals with that type of equipment should also be competent.
Carry out checks often enough that equipment doesn't become unsafe in the meantime. Record how often you intend to check equipment, then ensure the checks are carried out, with the results recorded. If you find too many faults, or any severe ones, you should start to make checks more frequent.
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Your electrical wiring
Ensure that your electrical installation is safe:
- Install new electrical wiring of a suitable standard (eg BS 7671) then maintain it in a safe condition
- De-energise any part of an installation that's become obviously defective between tests until the fault can be fixed
- Provide enough power sockets: overloading sockets by using adaptors can cause fires
Have your installation inspected and tested by a competent person, like a contractor approved by:
- The Electrical Contractors Association (ECA)
- National Inspection Council for Electrical Installation Contracting (NICEIC)
- The Electrical Contractors' Association of Scotland (SELECT)
Only allow competent people to do electrical work
This means someone with appropriate technical knowledge and experience. This can mean successfully completing an assessed training course run by an accredited training organisation. The course must include the type of work in question. For general electrical work, this could be an electrical apprenticeship with some experience.
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Provide a safety device
If you're using equipment operating at 230 volts (mains voltage) or higher, you should use an RCD (residual current device), which automatically switches off the power if it detects a fault. It should be installed in the main switchboard or the power socket, to permanently protect the supply cables. If this isn't possible you can use a plug with an RCD or a plug-in RCD adaptor. The rated tripping current (sensitivity) should be not more than 30 milliamps (mA). Remember:
- an RCD is a valuable safety device, never bypass it
- if the RCD trips there’s a fault, so 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
- use the RCD test button regularly, perhaps every three months
Work safely
Make sure:
- suspect or faulty equipment is taken out of use, labelled as ‘'DO NOT USE' and kept secure until examined by a competent person
- switch off tools and power sockets before plugging in or unplugging
- switch off and unplug equipment before cleaning or making adjustments
You must not allow work on or near exposed live parts unless it's absolutely unavoidable and suitable precautions have been taken to prevent injury, both to the workers and anyone else in the area.
Underground power cables
If your work involves digging in the road, pavement or near buildings, always assume cables are present. Use up-to-date service plans, cable avoidance tools and safe digging practice to avoid danger. Service plans are available from regional electricity companies, local authorities, highways authorities, etc.
Overhead power lines
When working near overhead lines, you might be able to get them switched off, if you give the owners enough notice. If this can't be done, ask for the safe working distance from the cables. Remember that electricity can flash over from overhead lines even when equipment isn't touching them.
Electrified railways and tramways
If you’re working near electrified railways or tramways, consult the operating company. Remember that some use electrified rails rather than overhead cables.
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