1. Electric wiring
1.1. 3-pin plug
1.1.1. Live wire
1.1.1.1. at 230V
1.1.1.2. Fuse is connected to live wire
1.1.1.2.1. Q: Which rating of a fuse should we use for an electric fan that requires a current of 8A to function? A: 5A B: 8A C: 10A D: 15A
1.1.2. Neutral wire
1.1.2.1. at 0V
1.1.3. Earth wire
1.1.3.1. at 0V
1.1.3.1.1. collects and transfers current leakage away to the ground.
1.2. What about 2-pin plug?
2. Electrical energy consumed (kWh) = Power (kW) x Time (h)
2.1. Q: Compute the energy (in kWh) used by a 60W fan when the fan is on for 6 hours.
3. Electrical hazards
3.1. Damaged insulation.
3.1.1. risk of short circuit and electrocution
3.2. Overloading of power socket
3.2.1. risk of overheating and fire outbreak.
3.3. Damped conditions.
3.3.1. risk of short circuit and electrocution.
4. Safety measures in household electricity
4.1. Main switch
4.1.1. controls and cuts the electric supply to the whole house.
4.2. Fuses
4.2.1. melts to open a circuit if too large is current is passing through.
4.3. Circuit breakers
4.3.1. trips to open a circuit if too large a current is passing through.
4.4. Earth wire
4.4.1. collects and transfers current leakage away to the ground.