a) Use the equation P=IV where P is power in W, I is Current in Amps and V is voltage in volts. Rearrange to give I=P/V I=1000/230 = 4.34 A b) This is a wire connected to the metal casing of an electrical appliance. If the casing becomes live it provides a low resistance path to earth. The large current in the earth wire causes the fuse to blow causing the current to stop. This prevents electrocution.