1. break circuits F uses are used to break circuits if the current passing through it is TOO LARGE that may probably cause damages to the appliances.

2. Typical fuse ratings : 0.1 A, 0.5 A, 1 A, 3 A, 5A, 13 A, 15 A, 30A, etc. * If the current in the circuit is greater than the fuse rating, the fuse breaks the circuit then. * Heater (220V, 2200 W) Operating current or max. current = P / V = 2200 / 220 = 10 A Which fuse rating should be chosen in order to protect the heater? A. 5AB. 10AC. 13AD. 15A * e.g. Operating current (max. current)Fuse rating chosen 0.25 A 0.5 A 2.5 A 3 A 3.5A 5A 1A 3A 5A

3. C ircuit Breaker

4. Electricity Meter / Kilowatt-hour meter (kWh meter) 1 kWh = * kWh : unit of electricity * 1 kWh = 1 unit = (1000 W) (60 x 60 s) = 3600 000 J (1 kW) (1 hr)

5. Units consumed consumed Amount charged for electricity The HongKong Electric Co. Ltd 香港電燈有限公司

6. Name & Address China Light and Power Hong Kong Ltd 中華電力有限公司 Total units consumed = 713 For first 400 units, $0.862 per unit. Others : $0.932 per unit Total amount charged for electricity = $ 344.80 + $291.72 = $ 636.52 Average cost of electricity = $ 636.52 / 713 = $ 0.893 Other charges