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City & Guilds Construction

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Know how to work with electrical equipment in the workplace

Unit 201: Health safety and welfare in construction



Objectives

By the end of this session you will be able to:

• State precautions to take to avoids risk to self and others when working with electrical equipment

• Identify voltage and voltage colour coding that are used in the workplace

• State methods of storing electrical equipment



The dangers of using electrical equipment

Electricity can kill or severely injure people and cause damage to property.

What are the hazards?

The main hazards of working with electricity are:

• Contact with live parts causing shock and burns – normal mains voltage, 230 volts AC, can kill

• Faults which could cause fire

• Fire or explosion where electricity could be the source of ignition in a potentially flammable or explosive atmosphere.

Electric shocks can also lead to other types of injury, for example by causing a fall from ladders or scaffolds etc.




What do I have to do?

You must ensure an assessment has been made of any electrical hazards, which covers:

• Who could be harmed by them

• How the level of risk has been established

• The precautions taken to control that risk

The risk assessment should take into consideration the type of electrical equipment used, the way in which it is used and the environment that it is used in.The risk of injury from electricity is strongly linked to where and how it is used. The risks are greatest in harsh conditions, for example:

• In wet surroundings – unsuitable equipment can easily become live and can make its surroundings live

• Outdoors – equipment may not only become wet but may be at greater risk of damage

• In cramped spaces with a lot of earthed metalwork such as inside a tank – if an electrical fault developed it could be very difficult to avoid a shock.




Cables, plugs sockets and fittings must be robust enough and adequately protected for the working environment.

Users of electrical equipment, including portable appliances, should carry out visual checks. Remove the equipment from use immediately and check it, repair it or replace it if:

• The plug or connector is damaged

• The cable has been repaired with tape, is not secure, or internal wires are visible etc

• Burn marks or stains are present (suggesting overheating)

Underground cables

• Always assume cables will be present when digging in the street, pavement and/or near buildings

• Consult local electricity companies and service plans to identify where cables are located




Avoiding danger from overhead power lines

Every year people at work are killed or seriously injured when they come into contact with live overhead electricity power lines. These incidents often involve:

• machinery, eg cranes, lorry-loader cranes,

• combine harvesters, and tipping trailers;

• equipment, eg scaffold tubes and ladders;

• work activities, eg loading, unloading, lifting, spraying, and stacking.




If a machine, scaffold tube, ladder, or even a jet of water touches or gets too close to an overhead wire, then electricity will be conducted to earth. This can cause a fire or explosion and electric shock and burn injuries to anyone touching the machine or equipment. An overhead wire does not need to be touched to cause serious injury or death as electricity can jump, or arc, across small gaps.

One of the biggest problems is that people simply do not notice overhead lines when they are tired, rushing or cutting corners. They can be difficult to spot, eg in foggy or dull conditions, when they blend into the surroundings at the edge of woodland, or when they are running parallel to, or under, other lines.

Always assume that a power line is live unless and until the owner of the line has confirmed that it is dead.




Legal Requirements

The legislation of specific relevance to electrical maintenance is the Health & Safety at

Work Act 1974, the Management of Health & Safety at Work Regulations 1999, the

Electricity at Work Regulations 1989, the Workplace (Health, Safety and Welfare)

Regulations 1992 and the Provision and Use of Work Equipment Regulations 1998.



The dangers of using electrical equipmentPAT Testing

Pat testing or portable appliance testing is an important part of any health & safety policy. The Health

& Safety Executive states that 25% of all reportable electrical accidents involve portable appliances.

The Electricity at Work Regulations place a legal responsibility on employers, employees and self-

employed persons to comply with the provisions of the regulations and take reasonably practicable

steps to ensure that no danger results from the use of such equipment. This in effect requires the

implementation of a systematic and regular program of maintenance, inspection and testing. The

Health & Safety at Work Act (1974) places such an obligation in the following circumstances:

• Where appliances are used by employees.

• Where the public may use appliances in establishments such as hospitals, schools, hotels, shops etc.

• Where appliances are supplied or hired.

• Where appliances are repaired or serviced.



Identifying Voltages

Cable connectors will be coloured as follows:

Yellow - 110 volt,

Blue - 230 volt,

Red – 410 volt



Identifying Voltages

If using 240 volt an RCD must be used.

An RCD, or residual current device, is a life-saving device which is designed to prevent you from getting a fatal electric shock if you touch something live, such as a bare wire. It can also provide some protection against electrical fires. RCDs offer a level of personal protection that ordinary fuses and circuit-breakers cannot provide

An RCD constantly monitors the electric current flowing through one or more circuits it is used to protect. If it detects electricity flowing down an unintended path, such as through a person who has touched a live part, the RCD will switch the circuit off very quickly, significantly reducing the risk of death or serious injury.



Methods of storing electrical equipment Before storing or using any electrical equipment 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.



Methods of storing electrical equipment

• Disconnect tools when not in use

• Never leave a tool running

• Pull the plug, not the lead when disconnecting

• Carry tools safely

• Maintain tools with care

• Store in a safe place

All electrical equipment and power tools need to be stored in a dry environment.

Damp or water and electrical tools do not mix and can make the tool dangerous to use.




Activity

Using activity sheet 16 students should get into groups to discuss and identify examples of the hazards of working with electricity.



Any questions?

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electrical hazards

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