Domestic Electricity Flashcards
(28 cards)
What three wires are in a ring main
Live wire
Neutral wire
Earth wire
What colour is the live wire
Brown
What colour is the neutral wire
Blue
What colour is the earth wire
Green and yellow
What is the live wire
Carries current to an appliance at a high voltage
What is the neutral wire
Completes the circuit and carries current at zero voltage.
What is the Earth wire
A safety wire that takes high voltage electricity away from the appliance into the earth if something goes wrong
What is an example of when the earth wire is used
Short circuit
Advantages of Ring Main (5)
-There are two paths for current
- cables can be made thinner
- each part of the cable carries less current
- convenient - sockets can be placed anywhere on the ring
- each socket has 230V applied and they can be operated separately
Unit for equation E = P x T
Energy(J) = Power(W) x Time (s)
What is the unit for power
watts
.
Hours
What is the “unit’ for energy
Kilowatt hours
What is another word for Kilowatt hour
A ‘unit’
What is ac
Alternating current
What is dc
Direct current
What is direct current
Flows in a constant direction. Produced from batteries in devices.
What is alternating current
Current that alternates, or changes constantly. It is produced by power plants and comes out of plug sockets.
What is an MCB
Miniature circuit breaker
RCCB
Residual Current Circuit Breaker
How does a miniature circuit breaker work
Current surges and becomes to high. The electromagnet becomes stronger and the circuit broken.
How does an RCCB work
There is a difference in current between the live and neutral wire. The electromagnetic grows stronger on one side, breaking the circuit.
How is an MCB better than a fuse
- it reacts faster/more sensitive
-it is reusable
When would an RCCB be used
When the neutral wire is cut by a power tool
