Dangers of Electricity

• Hazards:

  • Damaged insulation: contact with the wire (live wire especially) due to gap in the insulation causes electric shock which can cause serious injury or shock.

  • Overheating of cables: when long extension leads are coiled up, they may overheat. The current warms the wire, but the heat has less area to escape from a tight bundle. This might cause a fire.

  • Damp conditions: water can conduct a current, so if electrical equipment is wet someone might get electrocuted

• Fuse:

  • A fuse protects a circuit.

  • Thin piece of wire which overheats and melts if current is too high.

  • It is placed on the live wire before the switch.

  • This prevents overheating and catching fire.

  • A fuse will have a specific current value (e.g. 13 Amps.) so when choosing a suitable fuse, you must use the one above minimum value but less than maximum value

• Circuit Breaker:

  • An automatic switch which if current rises over a specified value, the electromagnet pulls the contacts apart, breaking the circuit.

  • The reset button is to rest everything.

  • It works like a fuse but is better because it can be reset.

• Benefits of Earthing a Metal Case:

  • Many electrical appliances, have metal cases, the earth wire creates a safe route for current to flow through if the live wire touches the casing

  • Earth terminal connected to metal casing, so in such a case, the current goes through earth wire instead of causing an electric shock.

  • A strong current surges through earth wire because it has very low resistance

  • This breaks the fuse and disconnects the appliance