RIT revision

1

Revision

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1

Fig 1

Fig 1 shows the person receiving an electric shock. This form of electric shock is
known as

A direct contact.

B switch contact.

C ground contact.

D indirect contact.

2 Name the background colour of the ‘Danger’ sign used in electrical equipment.

A Red.

B Blue.

C Green.

D Yellow.

3
One of the possible situations a person will receive a much lesser degree of electric
shock is when he is

A walking barefoot on a carpet.

B in a bathroom after a shower.

C sitting on a field and having his lunch.

D leaning on a metallic lamp post waiting for his bus to arrive.

4

Fig 4

Fig 4 shows a low voltage distribution to a number of bungalows in a private
housing estate. The name of cable used marked ‘X’ is the

A feeder.

B distributor.

C service cable.

D transmission cable.

2

5

Fig 5

Fig 5 above shows the electrical transmission in Singapore. Identify the location of
the power station marked ‘X’.

A Tuas Power Station.

B Jurong Pier Power Station.

C Upper Jurong Power Station.

D Pulau Seraya Power Station.

6

Fig 6

Fig 6 shows how electricity is generated by energy conversion through 3 stages.
The type of equipment in the mechanical energy stage is the

A pump.

B boiler.

C turbine.

D condenser.

7 Which one of the methods of producing electricity as listed below is classified by
environmentalists as pollution-free?

A Waste.

B Nuclear.

C Solar power.

D Tidal barrages.

8 In a multi-storey building with rising main distribution, the supply to each floor is
connected to it by means of

A tap-off units.

B cut-out units.

C fuse switched.

D circuit breaker.

3

9

Fig 9

Fig 9 shows a typical consumer unit installed in early HDB flats. Nowadays, the
new high rise flats have an additional protective device known as

A security alarm.

B surge arrestor.

C double-pole miniature circuit breaker.

D double-pole moulded case circuit breaker.

10

In Singapore, if a consumer receives a voltage at 200V single-phase ac and is
found to be low for use, what will be the minimum voltage allowable?

A 210 V.

B 216.2 V.

C 220.08 V.

D 230 V.

11

Which one of the following supply and load connections to the kilo-watt-hour
(kWh) meters is correct?

Fig 11

A Meter (a).

B Meter (b).

C Meter (c).

D Meter (d).

12

If in a single-phase consumer have a load requirement of 9.2kVA, 230V, 50Hz,
single-phase, its current rating would be

A 32 A.

B 40 A.

C 63 A.

D 100 A.

4

13

Which of the following accessories is designed with tripping mechanism?

A Plug.

B Switch.

C Ballast.

D Circuit breaker.

14

Home owners living in bungalows or landed property have the meterboard located
at the

A car porch.

B gate pillar.

C store room.

D overground (OG) box.

15

Fig 15

Fig 15 shows a final connection to an electric motor through a flexible conduit. In
isolation and switching, the device marked, ‘A’ should be

A an isolator.

B a contactor.

C a switch fuse.

D a circuit breaker.

16

Fig 16

Fig 16 shows an electric oven. In earthing, the metal case indicated is known as

A earth plate.

B circuit protective conductor.

C extraneous conductive part.

D exposed conductive part.

5

17

Which one of the following earthing electrodes is commonly used in Singpore?

A Earth rod.

B Earth tape.

C Earth plate.

D Structural framework.

18

Fig 18

Fig 18 illustrates a TN-S earthing system. The part marked ‘X’ in consumer
installations should be identified as

A Earth electrode.

B Main earthing terminal.

C Exposed conductive part.

D Extraneous conductive part.

19

Fig 19

In isolation and switching, the switch mounted next in a weather-proof socket
outlet as shown in Fig 19 shall be categorized as

A isolation.

B functional switching.

C emergency switching.

D switching off for mechanical maintenances.

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20

Fig 20

Identify the type of protective conductor used in the earthing installation marked
‘X’ in Fig 20.

A Earthing conductor.

B Circuit protective conductor.

C Main equipotential bonding conductor.

D Supplementary equipotential bonding conductor.

21

According to Table 54G in the CP5, the size of the protective conductor with the
same material as the phase conductor of 25mm² shall be

A 10 mm².

B 16 mm².

C 25 mm².

D 50 mm².

22

Fig 22

Fig 22 shows an earthing bonding connection for a water meter. According to
requirements, what would be the maximum distance allowable shown marked ‘X’?

A 300 mm.

B 500 mm.

C 600 mm.

D 1 000 mm.

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23

Class II equipment requires additional safety precautions to be taken, which one of
the following appliances is more likely to belong to that class?

A Kettle.

B Hair dryer.

C Electric oven.

D Water heater.

24

In earthing, what is the correct name for earth wire or cable?

A Earthing conductor.

B Circuit protective conductor.

C Main equipotential bonding conductor.

D Supplementary equipotential bonding conductor.

25

In earthing, which one of the following conditions is correct for a good earth?

A Reliable.

B High electrical resistance.

C Permit corrosion resistance.

D Able to carry low fault current repeatedly.

26

Fig 26

Refer to Fig 26, what is minimum depth, marked ‘X’ from the ground surface for
the laying of the earthing conductor in the ground?

A 500 mm.

B 1 000 mm.

C 1 500 mm.

D 2 000 mm.

27

Singapore implements the new cable colour code for fixed wiring in March 2009.
What is the new colour code for single-phase cable for Phase, Neutral and
Protective conductors respectively?

A Red, Black and Green.

B Yellow, Blue and Green/Yellow.

C Brown, Blue and Green/Yellow.

D Brown, Black and Green/Yellow.

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28

One disadvantage of PVC conduit is its unsuitability for use at temperatures

A between 20˚C and 39˚C.

B between 40˚C and 49˚C.

C between 50˚C and 59˚C.

D above 60˚C.

29

Fig 29

Identify the type of trunking shown in Fig 29?

A Comice trunking.

B Skirting trunking.

C Architrave trunking.

D Uneven-Compartment trunking.

30

For electrical services, what is the color code for electrical conduit?

A Blue.

B Orange.

C Red.

D Yellow.

31

The acronym ‘BC’ used for lamp holder specifications stands for

A Base Cap.

B British Cap.

C Batten Cap.

D Bayonet Cap.

32

Fig 32

The mercury vapor lamp shown in Fig 32 is used only for industrial interiors or
exterior lighting because

A It requires no special control gears.

B It has poor colour rendering properties.

C It has good colour output as halogen lamps.

D It is specially designed for industries and streets.

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33

Which type of wiring system required a high-sensitivity direct-acting current-
operated circuit breaker?

A Surface.

B Cable tray.

C Concealed.

D Under-floor.

34

A single-pole switch controlling an ac circuit shall be connected to the

A Phase conductor.

B Earth conductor.

C Neutral conductor.

D Circuit protective conductor.

35

A ceiling rose cannot be used for voltage exceeding

A 200 V.

B 230 V.

C 250 V.

D 500 V.

36

Fig 36

Fig 36 shows a schematic diagram of a 2-way and intermediate switch circuit. An
owner decided to add a new intermediate switch in the circuit. Which one of the
following connections is not functionally correct?

A

B

C

D

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37

Fig 37

Fig 37 is a symbol for a/an

A limit switch.

B two-way switch.

C double-pole switch.

D intermediate switch.

38

Fig 38

In Fig 38, the control of the lamp from 3 positions is known as

A one-way switching.

B two-way switching.

C double-pole switching.

D two-way and intermediate switching.

39

What is the maximum number of final circuits connected to a 15/16A MCB?

A One.

B Unlimited.

C Three, if each circuit is rated at 5A.

D Dependent on the aggregate demand.

40

A spur connected to a ring circuit cannot be used in a/an

A office.

B kitchen.

C bedroom.

D living room.

41

Which one of the following statements is correct for a ring circuit?

A Minimum cable size is 4 mm².

B Each terminal of the earth link has only 1 cable.

C Each terminal of the neutral link has only 1 cable.

D There are 2 cables terminated at the associated mcb.

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42

Fig 42

Identify the type of final circuit shown in Fig 42.

A ring circuit.

B radial circuit.

C lighting circuit.

D rising mains circuit.

43

Plugs and socket-outlets used for high current appliances such as air-conditioners
are rated

A 6 A.

B 10 A.

C 15 A.

D 32 A.

44

Which one of the following methods is NOT correct for connecting non-fused
spurs to a ring final circuit?

A At joint boxes.

B At the origin of the ring circuit.

C At the terminals of socket-outlet.

D At an existing multiple socket-outlet spur.

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45

Fig 45

Fig 45 shows a portion of a ring circuit. Identify the part called Spur.

A Part (c) – Joint box.

B Part (d) – Socket outlet.

C Part (a) – Branch cable.

D Part (d) – Fused outlet box.

46

The minimum size of PVC insulated cable used in radial final circuit that serves a
floor area of 50m² is

A 1 mm².

B 1.5 mm².

C 2 mm².

D 2.5 mm².

47

If the switch for an ac appliance is connected to the neutral,

A the appliance cannot be switched off.

B no current can pass through the appliance.

C the appliance will be live even with the switch off.

D excess current will flow through the appliance when switch is on.

48

Inspection and testing of an electrical installation is necessary to ensure

A equal distribution of loads.

B correct arrangement of cables.

C agreement with Fire Safety Act.

D compliance with CP5 regulations.

49

Visual inspection of rising mains in trunking is carried out to ensure that there are

A partition for each cable.

B fire barriers between floors.

C sufficient holes for ventilation.

D equipotential bonding between busbars.

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50

The polarity of an installation can be verified using an approved ohmmeter or

A An earth tester.

B Continuity tester.

C Loop impedance tester.

D Insulation resistance tester.

51

Fig 51

Fig 51 shows a method of performing a protective conductor continuity test. A
disadvantage of this method is that

A it requires a long test lead.

B the circuit breaker will operate.

C the test reading obtained is inaccurate.

D it will cause serious injury or electrocution.

52

Fig 52

Fig 52 above shows a ring circuit. IF the incoming and outgoing phase connections
at socket outlets B and E are disconnected respectively, there will be no supply to

A All the socket outlets.

B Socket outlets B and E.

C Socket outlets B, C, D and E.

D Socket outlets A, B, C and E.

53

One of the purposes for visual inspection of electrical installation is to ensure that
cable sizes conform to

A Customer’s requirements.

B Site supervisor requirements.

C Installation design requirements.

D Electrical engineer’s requirements.

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54

Visual inspection of devices for isolation and switching should be carried out to
ensure that they

A are of right brand.

B blend with the environment.

C are correctly located and installed.

D trip according to their overcurrent setting.

55

Tests are conducted on a ring final circuit to ensure that

A there are sufficient socket outlets.

B there is no isulation breakdown.

C the supply is connected to all the socket outlets.

D the ring circuit is not inter-connected or bridged.