This is pretty much the vital and core pieces of information you need to know in order to smash this dotpoint, in my opinion at least.
• When a current passes through a conductor, heat is generated
• The amount of heat generated increases as the current through the conductor increases
• Each piece of household wiring (e.g. lighting, power points, appliances) is designed to carry a certain maximum current without overheating
• Wiring that has to carry high current is made thicker to decrease the resistance and therefore, decrease the amount of heat generated
• If a wire is overloaded by passing excessive current through it, it can become hot enough to cause a fire
• In conclusion, there are different circuits in the house so that the current flowing through each is manageable, further allowing for safety to be maintained.
Hope it helped!