What you’ll learn5 learning objectivesChoose one objective for a focused lesson, or study the complete topic.4.4.1Hazards of: (a) damaged insulation (b)• State the hazards of: (a) damaged insulation (b) overheating cables (c) damp conditions (d) excess current from overloading of plugs, extension leads, single and multiple sockets when using a mains supplySyllabus objective4.4.2A mains circuit consists of a live• Know: a mains circuit consists of a live wire (line wire), a neutral wire and an earth wire and explain why a switch must be connected to the live wire for the circuit to be switched off safelySyllabus objective4.4.3Use and operation of trip switches and• Explain the use and operation of trip switches and fuses and choose appropriate fuse ratings and trip switch settingsSyllabus objective4.4.4Why the outer casing of an electrical• Explain why the outer casing of an electrical appliance must be either non-conducting (double-insulated) or earthedSyllabus objective4.4.5A fuse without an earth wire protects• State: a fuse without an earth wire protects the circuit and the cabling for a double- insulated applianceSyllabus objective