P5.2 - Cables And Plugs (Finishedish) Flashcards
How are most electrical appliances connected to the mains?
by three core cables
What are three core cables?
Cables with three wires inside them.
What colour represents what wire in a three-core cable?
Brown - live wire
Green and yellow (striped) - earth wire
Blue - neutral wire
What does the live wire of a plug do?
The live wire provides the alternating potential difference
What does the neutral wire of a plug do?
The neutral wire completes the circuit and carries away current (electricity in through live and out through neutral)
What does the earth wire of a three pin plug do?
The earth wire is used for protecting the wiring and safety. It stops the appliance from becoming live, carrying current only if there is a fault. (If a device with a metal case is plugged in, it automatically earths the case)
What materials is the three pin-plug made of?
Rigid plastic (casing)
Copper wire
Brass pins
Flexible plastic (cable insulation)
Why is rigid plastic used as the casing of a three pin plug?
Rigid plastic is used as it is a good insulator (safety) and doesn’t change shape
Why is flexible plastic used to insulate wires of a three pin plug?
The plastic is flexible so won’t break when bent and is practical. It is also a good insulator for safety
Why is copper used for the cables of a three pin plug?
Copper is a good electrical conductor and bends easily
Why is brass used for the pins of a three-pin plug?
Brass pins are used as they are good conductors and don’t rust
Why are two-core cables used for devices with plastic casings?
Plastic is a good insulator so won’t conduct electricity in case of a fault
What does the fuse contained in the three pin plug do?
If too much current passes through the wire in the fuse, it melts and snaps, cutting the live wire through
What are the parts of a three pin plug?
Fuse, earth wire, neutral wire, live wire, cable grip
