P4.4 Electrical safety

Describe the hazards of damaged insulation

• Insulation: the rubber/plastic around the wire

• If the insulation becomes damaged and you touch an exposed live wire, you will be electrocuted

Describe the hazards of overheating cables

• When a large current flows through a thin wire, it can cause the wire to heat up to very high temperatures and could potentially melt the insulator and cause a person to get an electric shock or cause a fire hazard

Describe the hazards of damp conditions

• Water (not pure water) conducts electricity, meaning you could be electrocuted by simply touching an electrical appliance when wet

Describe the hazards of overloading cables and appliances

• Plugging in too many devices at once creates excess current which produces heat and can pose a fire hazard

Describe a mains supply and its wires

• Electricity in our house is supplied in a circuit referred to as mains supply, which consists of:

  • A live wire: terminal which delivers current and has a switch connected to it

  • A neutral wire: terminal which carries current back to power source

  • An earth wire: safety measure designed to protect us from sudden voltage fluctuations

Describe the safety components of a mains supply

• Fuse: safety device containing thin metal filament that melts and cuts off the power supply in case of a surge in the electric current

• Trip switch (also known as circuit breakers): same function as fuses but are switches instead, and switch off when the current is too high

• Non-conducting casing: layer of insulation around the wires which is non-metallic

• Earthed casing: metal cases around an earth wire, earth wires provide safe route for current to flow (through earth rather than the person) in case of short circuit— this is because earth wires have lower resistance than the person