1. Electricity

2. Menu AC & DC Household Plugs & Fuses Power & Fuses

3. AC & DC

4. Alternating Current (AC) The current changes direction 50 times every second (frequency = 50Hz) Voltage Time AC is easier to generate than DC

5. Direct Current (DC) Voltage Time If the cell is reversed the current flows in the opposite direction The current only flows in one direction Return to menu

6. Household Plugs & Fuses

7. Wiring a plug Earth Wire Neutral Wire Fuse Live wire Cable grip Cable 1 2 3 4 5 6

8. Errors in Wiring Plugs 1. Bare wires showing 2. Proper fuse not installed 3. Earth Wire not connected 4. Live & Neutral wrong way round 5. Cable Grip loose

9. Dangerous Practices With Mains Electricity 1. Broken Plugs & Frayed Cables 2. Plugs & Cables near water 3. Overloaded sockets 4. Wet hands whilst using electricity

10. The Earth Wire Earth wires are always used in appliances with a metal case. If a fault develops in the appliance causing the live wire to touch the case, there is a surge in the current down the earth wire. This causes the fuse to blow.

11. Live & Neutral The Live wire alternates between high positive and high negative voltage with an average of about 230V The neutral wire is always at 0V. Electricity normally flows in and out of the live and neutral wires only

12. Fuses Symbol Car fuses A Fuse is a deliberate weak spot in a circuit

13. How Does a Fuse Work? Fuses are designed for safety. If a fault develops causing the live and neutral (or earth) wire to cross, a large current flows through the fuse and causes it to melt. This breaks the circuit and protects the appliance and user.

14. Fuse A deliberate weak spot. Melts and breaks the circuit with too much current Earth Wire Neutral Wire Live Wire Cable Grip Casing Brass Pins Complete the descriptions….. Return to Menu

15. Power & Fuses

16. Power, Current & Voltage Power is “the rate of doing work”. The amount of power being used in an electrical circuit is given by: P I V X Power = voltage x current (W) (V) (A) The unit of power is the watt (W)

17. Power and Fuses Complete the following table: AppliancePower Rating (W) Voltage (V)Current (A) Fuse Required (3, 5 or 13A) Toaster950230 Electric Fan Heater 2200230 Hairdryer330230 Floor Cleaner 1050230 Computer200230 HiFi80230 Return to Menu