Question 1

Electricity is generated in large commercial power-stations at:

Accepted Answer

A)  230 V 
B)  400 V 
C)  25 kV 
D)  132 kV.

Question 2

Which of the following fixing methods would be suitable for holding a lightweight load on a plasterboard partition?

Accepted Answer

A)  cable clip 
B)  Rawlbolt 
C)  screw fixing to plastic plug 
D)  spring toggle.

Question 3

Cutting off the electrical supply in order to ensure the safety of those working on the equipment is one definition of:

Accepted Answer

A)  basic protection 
B)  fault protection 
C)  equipotential bonding 
D)  isolation switching.

Question 4

A current which exceeds the rated value in an otherwise healthy circuit is one definition of:

Accepted Answer

A)  earthing 
B)  bonding 
C)  overload 
D)  short circuit.

Question 5

An appropriate wiring system for a three-phase industrial installation would be:

Accepted Answer

A)  PVC cables 
B)  PVC conduit 
C)  one which meets the requirements of Part 2 of the IET Regulations 
D)  one which meets the requirements of Part 5 of the IET Regulations

Question 6

The protection provided by insulating the live parts of the electrical installation is called:

Accepted Answer

A)  overload protection 
B)  short-circuit protection 
C)  basic protection 
D)  fault protection.

Question 7

The cables suspended from the transmission towers of the National Grid network are made from:

Accepted Answer

A)  aluminium and porcelain. 
B)  copper and brass 
C)  copper with PVC insulation 
D)  aluminium and steel

Question 8

The gas, water and central heating pipes of the building not forming a part of the electrical installation are called:

Accepted Answer

A)  earth conductors 
B)  bonding conductors 
C)  exposed conductive parts 
D)  extraneous conductive parts.

Question 9

An over-current resulting from a fault of negligible impedance is one definition of:

Accepted Answer

A)  earthing 
B)  bonding 
C)  overload 
D)  short circuit.

Question 10

The linking together of the exposed or extraneous conductive parts of an installation for the purpose of safety is one definition of:

Accepted Answer

A)  earthing 
B)  protective equipotential bonding 
C)  exposed conductive parts 
D)  extraneous conductive parts.

Question 11

Electricity is transmitted at very high voltages because for a given power the:

Accepted Answer

A)  current is reduced 
B)  current is increased 
C)  losses are reduced 
D)  losses are increased.

Question 12

A current which exceeds the rated current in an otherwise healthy circuit is one definition of:

Accepted Answer

A)  fault protection 
B)  an over-current 
C)  an overload current 
D)  a short-circuit current.

Question 13

A load connected to the three phases of a star-connected three-phase fourwire supply system from the local substation would have a voltage of:

Accepted Answer

A)  230 V 
B)  400 V 
C)  25 kV 
D)  132 kV.

Question 14

The protection provided by equipotential bonding and automatic disconnection of the supply is called:

Accepted Answer

A)  extraneous conductive parts 
B)  basic protection 
C)  exposed conductive parts 
D)  fault protection.

Question 15

The phase voltage of a delta-connected load is 100 V. The line voltage will be:

Accepted Answer

A)  57.73 V 
B)  101 V 
C)  173.2 V 
D)  231 V.

Question 16

'The conductive mass of the earth' is one definition of:

Accepted Answer

A)  earth 
B)  earthing 
C)  bonding conductor 
D)  circuit protective conductor.

Question 17

An appropriate wiring method for a high-temperature installation in a boiler house is:

Accepted Answer

A)  metal conduit installation 
B)  trunking and tray installation 
C)  FP 200 cables 
D)  MI cables.

Exam 3: Principles of Electrical Science