2.17 Plugs & Wires Flashcards
What colour is the live wire?
Brown
What does the live wire do?
The live wire carries the voltage (potential difference, p.d.). It alternates between a high positive and negative voltage of about 230V.
What colour is the neutral wire?
Blue
What does the neutral wire do?
The neutral wire completes the circuit - when the appliance is operating normally, current flows through the live and neutral wires. It is around 0V.
What colour is the earth wire?
Green and yellow
What does the earth wire do?
The earth wire is for safety. It carries the current away if something goes wrong. It’s also at 0 V.
What are all the wires in the plug made from?
Copper
What are all the wires in the plug covered in?
Insulating plastic
What is the p.d. between the live wire and the neutral wire?
The p.d. between the live wire and the neutral wire equals the supply p.d. (230 V)
What is the p.d. between the live wire and the earth wire?
The p.d. between the live wire and the earth wire is also 230 V for a mains - connected appliance.
Is there a p.d. between the neutral wire and the earth wire?
No. They’re both at 0 V.
What is an example of an earthed conductor and why?
- Your body is an example of an earthed conductor, and is also at 0 V. This means if you touched the live wire, they’d be a large p.d across your body and a current would flow through you. This large electric shock could injure you or even kill you.
- Even if a plug socket is off (i.e. the switch is open) there is still a danger you could get an electric shock. A current isn’t flowing, but there is still a p.d. in the live part of the socket, so your body could provide a link between the supply and earth if you made contact with it.
In the UK, the mains supply is alternating current and has a frequency of ___ Hz and a voltage of _____ V.
50, 230
Which wire prevents the electrical casing from becoming live?
Earth wire
Which wire supplies the current to the appliance?
Live wire
