P5.2 Cables and plugs Flashcards
What does the earth wire do?
Stops the metal case becoming live if the live wire breaks and touches the case
What is the p.d of an earth wire?
0V and only carries current if there is a fault
What is the purpose of the longest pin?
Designed to make contact with the earth wire of a wall socket circuit - so when you plug an appliance with a metal case into a wall socket - the case is automatically earthed
Why are the pins made up of brass?
Brass is a good conductor and does not rust
What is the purpose of the fuse?
When current is too high the current passes through the wire in the fuse - it melts and cuts the live wire off
What is the colour of the live wire?
Brown - has a voltage of 230 V
What is the colour of the neutral wire?
Blue - and completes the circuit
What is the colour of the earth wire?
Green and yellow
Why is copper used for the wire?
Because it is a good electrical insulator and bends easily
What is a short circuit?
When the live wire inside the appliance touches a neutral wire - a very big current passes between the 2 wires
What happens when someone touches a live wire?
People’s bodies are at 0v - if someone touches it - a big potential difference will act across their body - causing a current to flow through them - they will suffer an electric shock
Why do appliances with a metal case must have three core cables?
So metal case is earthed
