Secondary effects

Secondary injuries can follow an electric shock. These are any injury that results indirectly from receiving a shock. A person may jerk away, lose their balance or fall from height if they are working at height, and injure another part of their body.

Work near overhead power lines

Accidental contact with live overhead power lines can cause serious injuries and deaths. People can also be hurt when a person or object gets too close to a line and a flashover occurs. Work involving high vehicles or long equipment is particularly high risk, such as cranes, mobile elevating work platforms (MEWPs), scaffold poles and ladders. Remember:

• Electricity can arc, or flash over, across a large distance, so equipment or people close to power lines can still be in danger of damage, injury or death even without touching the lines.
• Voltages lower than 230 volts can kill and injure.
• Do not mistake overhead power lines on wooden poles for telephone wires.
• Electricity can bypass wood, plastic or rubber if it is damp or dirty, and cause fatal shocks. Do not rely on gloves or rubber boots to protect you.

The requirements are set out in HSE guidance note GS6, Avoiding danger from overhead power lines.

Contact with underground power cables during excavation

Striking underground cables often causes burn injuries from the resulting explosion. It may also cause electric shock if contact is made with live conductors. These incidents often kill or seriously injure people, damage equipment and interrupt electricity supplies. Damage can be caused when a cable is:

• cut through by a sharp object such as the point of a tool
• crushed by a heavy object or powerful machine

Summary notes for Element 11 · Cheat sheet · Glossary. A study aid, not published or endorsed by NEBOSH.