1Which of the following best describes the UK mains electricity supply?50 V, 230 Hz a.c.230 V, 50 Hz d.c.50 V, 230 Hz d.c.230 V, 50 Hz a.c.2In a three-core electricity cable, which of the following wires is covered by green and yellow plastic?The neutral wireThe earth wireThe fuse wireThe live wire3Under normal operating conditions, which of the wires in a three-core cable carry an electric current?The live and earth wires onlyThe neutral and earth wires onlyThe live and neutral wires onlyThe live wire only4An electric kettle is labelled as having double insulation.  Which electrical wire will be missing from its power cable?NeutralEarthLiveIt’s a trick question – the kettle will require all three wires to operate5Which of the following types of electrical wires poses the greatest safety risk, especially when frayed or damaged?NeutralLiveEarthAll electrical wires pose the same risk to safety6A television is connected to the mains supply using a three-core cable.  Where in this circuit should the protective fuse be placed?Along the live wireInside the televisionAlong the earth wireAlong the neutral wire

Most electrical appliances are connected to the mains using a three-core cable. Name the wires found in these cables:

fuse or a circuit breaker may be used to protect the circuit.One type of circuit breaker is a Residual Current Circuit Breaker (RCCB).(a) (i) Use the correct answer from the box to complete the sentence.earth live neutralA fuse is connected in the ........................................... wire.(1)(ii) Use the correct answer from the box to complete the sentence.are bigger are cheaper react fasterRCCBs are sometimes preferred to fuses because they........................................... .(1)(iii) RCCBs operate by detecting a difference in the current between two wires.Use the correct answer from the box to complete the sentence.earth and live earth and neutral live and neutralThe two wires are the .............................................................................. wires.(1)(b) An RCCB contains an iron rocker and a coil.A student investigated how the force of attraction, between a coil and an iron rocker,varies with the current in the coil.She supported a coil vertically and connected it in an electrical circuit, part of whichis shown in the figure below .

An electric kettle is labelled as having double insulation.  Which electrical wire will be missing from its power cable?NeutralEarthLiveIt’s a trick question – the kettle will require all three wires to operate

Earth Wire and Its Functions

The potential difference across the mains power supply in the UK is