cables and plugs.

Question 1

what is the voltage of the mains electricity on the UK?

Answer 1

230v.

Question 2

how many times does the mains electricity change direction?

Answer 2

50 times a second.

Question 3

if the mains electricity changes direction 50 times a second what does that mean the frequency is?

Answer 3

50 Hz.

Question 4

the mains supply uses what type of cable?

Answer 4

3 core cable.

Question 5

what does each cable carry that is different?

Answer 5

electrical potential.

Question 6

what is the name of the wire that is: brown: and what is its voltage potential?

Answer 6

live wire.
230 v potential.

Question 7

what is the name of the wire that is: blue : and what is its voltage potential?

Answer 7

neutral wire.
at or close to 0v earth potential.

Question 8

what is the name of the wire that has: green and yellow strips: and what is its voltage potential?

Answer 8

earth wire.
o v potential.

Question 9

during operation: what does the potential difference cause to flow and where?

Answer 9

current.
live and neutral wire.

Question 10

during operation: the live wire carries what from where?

Answer 10

alternating potential from supply

Question 11

during operation: what does the neutral wire do?

Answer 11

completes the circuit.

Question 12

during operation: what conditions allows only for the current to flow in the earth wire?

Answer 12

a fault connecting it to a non-zero potential.

Question 13

what can the earth wire be classed as and what does it do?

Answer 13

safety wire.
stops the exterior of an appliance becoming live.

Question 14

what circuit is used in house wiring?

Answer 14

parallel.

Question 15

why is that certain circuit used for house wiring?

Answer 15

otherwise everything would have to be on.

Question 16

what does the live wire carry?

Answer 16

electric current to an appliance.

Question 17

what does the neutral wire do?

Answer 17

completes the circuit.

Question 18

how does the neutral wire do its job?

Answer 18

forms a path for current to flow back to the mains.

Question 19

what is the potential difference between the neutral and earth wire?

Answer 19

usually close to 0V.

Question 20

how is the earth wire usually connected to the circuit?

Answer 20

metal case of an appliance.

Question 21

what does the earth wire provide?

Answer 21

very low resistance path for a current in the event of the appliance becoming live.

Question 22

what are cables usually made out of?

Answer 22

copper.

Question 23

why are cables usually made out of copper?

Answer 23

good conductor and bends easily.

Question 24

what is a good electrical insulator and prevents people getting an electrical shock if they touch the cable?

Answer 24

plastic.

Question 25

which wires are stored in a 2 core cable?

Answer 25

neutral and live.

Question 26

what are 2 core cables used in and why?

Answer 26

appliances with a plastic case as they don’t need to be earthed. double insulated.

Question 27

what is the symbol for a 2 core cable?

Answer 27

a box with a smaller one inside.

Question 28

what can be changed about a cable and where would we see it, technical terms and an example?

Answer 28

different thicknesses, different appliances.
cable for the cooker is thicker than the one for the lights.

Question 29

how does a fuse work: stage: 1.

Answer 29

energy is dissipated.

Question 30

how does a fuse work: stage: 2.

Answer 30

fuse wire gets hot.

Question 31

how does a fuse work: stage: 3.

Answer 31

if the current is larger than the current rating for the fuse it melts.

Question 32

how does a fuse work: stage: 4.

Answer 32

this disconnects the power supply to the appliance.

Question 33

how does a fuse work: stage: 5.

Answer 33

protects the appliance from taking a current that might damage it or cause the wiring to overheat.

Question 34

what happens if the live wire touches the metal case and what is large enough to do?

Answer 34

a large current flows to earth.
melt the fuse which cuts the power supply to the appliance.