Page 390 - IGC BOOK

11.1 Hazards and the Risks of Electricity

Introduction

Electricity can kill or severely injure people and cause damage to property. Every year many
accidents at work involving electric shock or burns are reported to the Health and Safety
Executive (HSE). Most of the fatal incidents are caused by contact with overhead power lines.

Even non-fatal shocks can cause severe and permanent injury. For example, shocks from faulty
equipment may lead to falls from ladders, scaffolds or other work platforms.

Those using or working with electricity may not be the only ones at risk – poor electrical
installations and faulty electrical appliances can lead to fire, which may also cause death or injury
to others. Most of these accidents can be avoided by careful planning and straightforward
precautions.

Electric Shock and its Effects on the
Body

An electrical phenomenon is caused by flow of
free electrons from one atom to another.
Electric current flow in conductor due to
potential difference or external force like how
the blood flow though the body by the pressure
produced by heart to pump blood to all blood
vessels.

Potential differences are measured in Volts.
Direct current (DC) is electrical current which
flows consistently in one direction. Whereas 1Basic Electric Circuit
the flow of electrons switches back and forth at
regular intervals is known as Alternating Current (AC),
for example, current flowing in powerlines and normal household electricity.

Relationship between Voltage, Current and Resistance

Electricity

Electricity is the flow of electrons, referred to as an electric current. The rate of flow of electrons
are measures in amperes (A); Smaller currents are measures in milliamps (mA)
Voltage

Potential energy is required to move electrons through a conductor, the potential difference
(Voltage) is the force or pressure moving the electrons through a circuit. Pressure in an electrical
system is also known as potential difference or electromotive force. When you say that a battery
has 12 volts, you really say that it has an electrical pressure of 12 volts.

ENSIGN | Unit IG2 – Element 11 – Electricity 1