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14 ELECTRICAL SAFETY

Electricity is a widely used, efficient and convenient, but potentially hazardous
method of transmitting and using energy. It is in use in every factory, workshop,
laboratory and office in the country. Any use of electricity has the potential to be very
hazardous with possible fatal results.
Legislation has been in place for many years to control and regulate the use of electrical
energy and the activities associated with its use. Such legislation provides a framework for the
standards required in the design, installation, maintenance, and use of electrical equipment and
systems and the supervision of these activities to minimize the risk of injury. Electrical work from
the largest to the smallest installation must be carried out by people known to be competent to
undertake such work.
New installations always require expert advice at all appropriate levels to cover both design
aspects of the system and its associated equipment. Electrical systems and equipment must be
properly selected, installed, used and maintained.
Approximately 8% of all fatalities at work are caused by electric shock. The majority of the
fatalities occur in the agriculture, extractive and utility supply and service industries, while the
majority of the major accidents happen in the manufacturing, construction and service industries.
Electrical safety is a system of organizational and technical measures and tools
that protect people from harmful and dangerous current electric arc, electromagnetic
field, and static electricity (Figure 14.1).

14.1 Principles of E lectricity and S ome D efinitions

Basic principles and measurement of electricity

In simple terms, electricity is the flow or movement of electrons through a
substance that allows the transfer of electrical energy from one position to another.
The substance through which the electricity flows is called a conductor. This flow or
movement of electrons is known as the electric current. There are two forms of
electric current – direct and alternating. Direct current (dc) involves the flow of
electrons along a conductor from one end to the other. This type of current is mainly
restricted to batteries and similar devices. Alternating current (ac) is produced by a
rotating alternator and causes an oscillation of the electrons rather than a flow of
electrons so that energy is passed from one electron to the adjacent one and so on
through the length of the conductor.

Figure 14.1 Beware of electricity – typical sign

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