Domestic Electricity

Question 1

What three wires are in a ring main

Answer 1

Live wire
Neutral wire
Earth wire

Question 2

What colour is the live wire

Answer 2

Brown

Question 3

What colour is the neutral wire

Answer 3

Blue

Question 4

What colour is the earth wire

Answer 4

Green and yellow

Question 5

What is the live wire

Answer 5

Carries current to an appliance at a high voltage

Question 6

What is the neutral wire

Answer 6

Completes the circuit and carries current at zero voltage.

Question 7

What is the Earth wire

Answer 7

A safety wire that takes high voltage electricity away from the appliance into the earth if something goes wrong

Question 8

What is an example of when the earth wire is used

Answer 8

Short circuit

Question 9

Advantages of Ring Main (5)

Answer 9

-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

Question 10

Unit for equation E = P x T

Answer 10

Energy(J) = Power(W) x Time (s)

Question 11

What is the unit for power

Answer 11

watts

Question 12

.

Answer 12

Hours

Question 13

What is the “unit’ for energy

Answer 13

Kilowatt hours

Question 14

What is another word for Kilowatt hour

Answer 14

A ‘unit’

Question 15

What is ac

Answer 15

Alternating current

Question 16

What is dc

Answer 16

Direct current

Question 17

What is direct current

Answer 17

Flows in a constant direction. Produced from batteries in devices.

Question 18

What is alternating current

Answer 18

Current that alternates, or changes constantly. It is produced by power plants and comes out of plug sockets.

Question 19

What is an MCB

Answer 19

Miniature circuit breaker

Question 20

RCCB

Answer 20

Residual Current Circuit Breaker

Question 21

How does a miniature circuit breaker work

Answer 21

Current surges and becomes to high. The electromagnet becomes stronger and the circuit broken.

Question 22

How does an RCCB work

Answer 22

There is a difference in current between the live and neutral wire. The electromagnetic grows stronger on one side, breaking the circuit.

Question 23

How is an MCB better than a fuse

Answer 23

• it reacts faster/more sensitive
  -it is reusable

Question 24

When would an RCCB be used

Answer 24

When the neutral wire is cut by a power tool

Question 25

Fuse

Answer 25

A thin wire that melts when the current is too high.

Question 26

Function of the fuse

Answer 26

Prevents the device from overheating

Question 27

Function of MCB

Answer 27

Prevent devices from overheating

Question 28

Function of RCCB

Answer 28

Protect the user from serious electric shock