domestic uses and safety

Question 1

is mains electricity an a.c supply or a d.c supply
what do each of these stand for

Answer 1

mains electricity is an a.c supply

.a.c = alternating current
.d,c=direct current

Question 2

define alternating current and direct current

Answer 2

. alternating current= current that countinously changes direction and a specific frequency

.direct current= one directional flow current

Question 3

what is the frequency and voltage of the UKs mains electricity supply

Answer 3

frequency=50hz
voltage- 230V

Question 4

how many wires are usually in the cables connecting electrical appliances to the mains. name these wires

Answer 4

. live wire
.nuetral wire
.earth wire

Question 5

state the insulation colour used on the earth wire

Answer 5

green and yellow stripes

Question 6

state the insulation colour used on the live wire

Answer 6

brown

Question 7

state the insulation colour used on the neutral wire

Answer 7

blue

Question 8

explain why the earth wire does and doesent carry current

Answer 8

. under normal circumstances, no current flows through the Earth wire

. if a fault occurs in the appliance , current will flow to the ground

Question 9

what potential is the nuetral wire at

Answer 9

0 volts

Question 10

state the potential difference between the live and earth wires

Answer 10

230 volts

Question 11

what is the purpouse of the nuetral wire

Answer 11

to complete the circuit by connecting the appliance back to the main supply

Question 12

for metal appliances , where is the earth wire connected to
why

Answer 12

. earth wire is connected to the metal casing of the appliance

.if live wire, becomes loose and touches the casing,the current will flow through the earth wire , preventing electrocution