4. Wiring in 3pin Plug
Live pin
Neutral
Earth Wire
Cable grip
4
Neutral
pin
Live Wire
Earth pin
5. 5
Wiring in 3pin Plug
Plastic insulation
Metal conductor
Plastic outer casing
6. Safety devices: Fuses
• Fuse contains a thin piece
of wire made from a
metal that has a low
melting point.
• If the current is too large
in the circuit, the fuse
wire becomes very hot
and melts.
Symbol of a fuse
6
7. 7
Safety devices: Fuses
5A
3A
4A
3A 5A
4A
Electrical
appliance
Electrical
appliance
Electrical
appliance
Electrical
appliance
Case 1 Case 2
Correct fuse for a circuit is the one that allows the correct current
but blows if the current is a little large
8. 8
Safety devices: Circuit breaker
• A circuit breaker cuts off the
current if too much current
flows.
• They are used to protect the
ring of sockets in a house.
(Often called ring main.)
9. 9
Reducing risks from electrical hazard
• Never poke things into socket.
• Never touch bare metals of plugs.
• Keep electricity away from water and don’t use
switches with wet hands.
• Do not plug too many things into one socket.
• Never use something with a damaged wire.
13. 13
4.
When the current is 6A, the fuse will melt.
5.
Never poke things into socket.
Never touch bare metals of plugs.
Keep electricity away from water and don’t use switches with wet hands.
Do not plug too many things into one socket.
Never use something with a damaged wire.
Editor's Notes
(Students will be paired. Then they will be given 4 min to discuss about each cases and someone will be picked randomly to present the answer.)
Everyday we use our mobile phone, TV, Laptop and tablets. All these devices use energy called electricity. Therefore, our lives will be really hard if there is no electricity. Before we start the lesson, I would like u work in pair and discuss on the 2 scenarios shown here. I will give u 3 min to discuss. So lets start now.
(Students will be paired. Then they will be given 4 min to discuss about each cases and someone will be picked randomly to present the answer.)
Everyday we use our mobile phone, TV, Laptop and tablets. All these devices use energy called electricity. Therefore, our lives will be really hard if there is no electricity. Before we start the lesson, I would like u work in pair and discuss on the 2 scenarios shown here. I will give u 3 min to discuss. So lets start now.
Here in Myanmar, the large majority of electricity comes from hydropower. The electricity is the distributed through national grid across the country to our homes . We got the electricity in our home through the main supply which is the socket. There are 2 important things to know about it. It has alternating current of 230Volts and frequency of 50Hz. Whenever we plug electrical appliances to the socket, we are actually connecting them to the main supply.
In this video , we are going to look at different wires that we find in plugs and cables and why touching the brown one can give u electric shock.
When we open up the plug we used at home, it usually consists of 3 core cable. The live wire, neutral wire and earth wire. Each of the wire is made of copper so that they can conduct electricity. And it is wrapped around by insulating plastic. The colour of insulating plastic is specific to the specific types of wire. That helps us to identify them.
The live wire is brown and it is the one that provides the alternating current from the main supply.
Meanwhile, the neutral wire blue completes the circuit by carrying away the current . This means electricity flows into the device through the live wire and flows out through the neutral wire.
Lastly we have earth wire which is stripe green and yellow. The earth wire doesn’t normally carry a current at all. Safety features
This is the pic of a fridge and here is someone opening the fridge door. As u can see, the electricity travels along the live wire and it goes out through neutral wire.
