1. Physics Module 2 Mains Electricity

2. What do you need to know Voltage and frequency of UK mains electricity Wiring of a 3-pin plug Properties of materials used to make the plug Errors in the wiring of a plug Safety features

3. What is Mains Electricity? It is generated in the power stations and is transported around the country along the National Grid. We connect to the mains by plugging in our appliances

4. What are the facts and figures? Mains electricity in the UK has a voltage of 230V It has a frequency of 50 Hertz (Hz). This means that it changes direction 50 times per second. It is an alternating current (a.c.)

5. How to wire a 3-pin plug

6. Which wire is which? The live wire is brown and is on the right The neutral wire is blue and is on the left The earth wire is at the top and is green and yellow (like a daffodil growing out of the earth)

7. What do the wires do? The live wire carries the current and the voltage. It is the dangerous wire. The neutral wire carries empty current and no voltage, it completes the circuit. The earth wire is the safety wire and it will allow current to flow to earth if there is a fault.

8. Fuses Fuses are there to melt if the circuit becomes too hot. This will break the circuit and stop the current flowing. It is important to fit the correct fuse

9. Which fuse? Some electrical appliances use a lot of electricity and so they need a heavy fuse like a 13A. Some don’t use much electricity and so need a lighter fuse like a 3A one

10. Which fuse? You must fit the correct fuse for the appliance or it could go on fire. The fuse must be greater than but as close as possible to the current of the appliance

11. Which fuse? The lamp will draw about 2A of current so which fuse would you choose? 13A5A 3A

12. The earth wire Appliances that have metal cases could become live if the live wire came loose and touched the case. The earth wire is fitted to the case and will carry any current safely to earth

13. Double insulation Appliances with a plastic case cannot become live and so they do not need an earth wire. Their cables will only contain a live wire and a neutral wire.