Topic 2 - req for elec safety

Question 1

New Colour Code for single phase

Answer 1

Brown - Live
Blue - neutral
green yellow - earth

Question 2

Common cause for insulation failure

Answer 2

wear and tear
physical damage
thermal stress
chemical exposure

Question 3

insul. failure leads to ?

Answer 3

electrical fire
safety hazard
equipment damage

Question 4

excess current due to ?

Answer 4

overload
short circuit

Question 5

overload is ?

Answer 5

too many appliances plugged into one socket

Question 6

short circuit is?

Answer 6

2 live from different phase or live and neutral come in contact with no load

Question 7

types of excess current protection

Answer 7

cartridge fuse
miniature circuit breakers

Question 8

How does a cartridge fuse work?

Answer 8

when the current is more than the fuse rating, the heat will melt the fuse and cut off the current flow

Question 9

how does a mcb work?

Answer 9

the coil will increase its magnetic field when the current increases and trip a switch cutting off the current

Question 10

what is earthing?

Answer 10

the leakage current flowing down to the earth

Question 11

what is a rccb?

Answer 11

it is a safety device installed in a DB to monitor the amount of current and if there is and imbalance in live and neutral, it will trip