Page 397 - IGC BOOK

• Extreme Temperature and pressure from machineries.

• Corrosive environment – chemical spill on the floor e.g. acids.
• Flammable atmosphere – presence of flammable substances such as vapours, dusts or gas.
• Contamination – caused by oils or debris.

The equipment must be robust and suitable for the environment to prevent foreseeable
mechanical damage. Cables protect against metal sheets in a heavy industry, or overheated
when running over the machinery, movement of vehicles over the cables causes abrasion.
Cables must be protected by rerouting away from environmental hazards or by armouring the
cables.

Protective Systems - Advantages and Disadvantages

Fuses

A fuse is an electric / electronic or mechanical device,
which is used to protect circuits from over current. A fuse
melts or break the circuit whenever there is heat
generated by the overcurrent. It disconnects the power
supply to the equipment to make the equipment safe. It is
important to ensure the correct fuse is used for the
appliance.

Example
A Printer requires 8 amp will be protected by a 10 amps fuse; hence it melts at overload
current than 10 amps and protect the printer.

Advantages Disadvantages
• Cheap • Does not protect people from electrocution

• Easy to replace • Slow operative

• Protect electrical equipment • Easy to bypass – replace incorrect rated
fuse.

ENSIGN | Unit IG2 – Element 11 – Electricity 8