2.3 understand the uses of insulation, double insulation, earthing, fuses and circuit breakers in a range of domestic appliances

2.3 understand the uses of insulation, double insulation, earthing, fuses and circuit breakers in a range of domestic appliances

Insulation: Some appliances are cased with insulators like plastic rather than metal to prevent user from receiving shock. This casing is called insulation.

Double Insulation: If all the pars of an appliance are insulated in such a way , so that electric current cannot be touched by the user, the appliance is said to have double insulation.

Earthing: Many appliances have a metal casing. This should be connected to earth wire so that if the live wire becomes frayed or breaks and comes into contact with the casing, the current will pass through the earth wire rather than the user. The current in the earth wire is always large enough to blow the fuse and turning off the circuit. So the user is safe from electric shock.

Fuses: Fuse is a safety device usually in the form of a cylinder or cartridge which contains a thing piece of wire made from a metal that has low melting point. If too large a current flows in the circuit the fuse wire becomes very hot and blows, shutting the circuit off. This prevents you getting a shock and reduces the possibility of an electrical fire. One the fault in the current is corrected, it should be replaced again.

Circuit Breakers: Circuit Breaker is similar to fuses. If too large a current flows in a current a switch opens making the circuit incomplete. Once the fault in the circuit is corrected, the switch is reset, usually by pressing a reset button.