Worksheets8202 March 2022
Total questions: 60
Worksheet time: 3600secs
Which Regulations are non-statutory?
The Electricity at Work Regulations.
Requirements for Electrical Installations BS 7671.
Control of Substances Hazardous to Health (COSHH) Regulations.
Control of Noise at Work Regulations.
Which may become a land pollutant if not contained safely?
Mercury
Argon
Neon
Nitrogen
Which type of fire extinguisher would have a red band?
CO2
Foam
Water
Powder
Who is responsible for organising construction work on a building site?
Site Manager
Clerk of Works
Quality Inspector
Principle Architect
What colour sign would tell you a safety helmet must be worn on a construction site?
Yellow and black
Green and white
Red and black
Blue and white
What unit is equivalent to A x 10^-3?
nA
μA
mA
kA
What is the diameter of a conductor with a cross sectional area of 6 mm^2?
1.27mm
1.38mm
2.24mm
2.76mm
Which is the correct transposition of X_L = 2πfL?
f = 2πL / X_L
f = X_L / 2πL
f = 2πX_L / L
f = πL / 2X_L
What is measured in m^2?
Area
Length
Width
Volume
How many degrees does a generator rotor rotate per cycle?
45°
90°
180°
360°
What is the SI unit of measurement for resistance?
Ohm
Watt
Henry
Farad
Which is a good conductor of electricity?
Mica
Nylon
Carbon
Ceramic
Which instrument is used to directly measure electrical current?
Voltmeter
Ammeter
Ohmmeter
Wattmeter
What is the resistance of a 65 m 1.5 mm^2 copper conductor where its resistivity is 0.0172 μΩm?
0.63Ω
0.65Ω
0.75Ω
0.94Ω
Three resistors of 17 Ω, 44 Ω and 66 Ω are connected in parallel. What is the total circuit resistance?
0.09 Ω
10.34 Ω
42.33 Ω
127.0 Ω
An ammeter is to be installed in the circuit shown in Figure 1. At which point in the circuit must this be installed in order to measure the total load current?
1
2
3
4
What is the total current in the circuit in Figure 2 if the ammeter reads 8 Amps?
6.6 A.
10.2 A.
37.3 A.
45.3 A.
What is the SI unit of measurement for capacitance?
Ampere
Farad
Henry
Weber
What is the unit of magnetic flux?
Watt
Tesla
Weber
Coulomb
Which electrical item would most commonly contain a permanent magnet?
Float switch in a water tank
Dimmer switch on a lighting circuit
Shower isolator in a bathroom
Security contact on a door
What does the thumb in Fleming’s Right Hand Rule represent the direction of?
Field
Motion
Current
Resistance
What force would be created by a current of 9.15 A flowing through 1800 mm of conductor with a flux density of 0.35 T?
1.78 N
5.76 N
47.0 N
5764.5 N
What is the formula used to calculate the RMS voltage on a 50 Hz sine wave?
V = Peak/2
V = Peak/√2
V = 1/(2 × Peak)
V = 1/(√2 × Peak)
What is the output voltage of the transformer shown in Figure 3 which is commonly used on construction sites?
12 V.
24 V.
110 V.
230 V.
A transformer has 239 primary and 29 secondary turns and has a secondary voltage of 400 V. What value is the input voltage?
1100 V.
3300 V.
11000 V.
33000 V.
Which electronic component is shown in Figure 4?
Transistor
Thermistor
Triac
Diac
Which component can be made by connecting four diodes?
Amplifier.
Capacitor.
Bridge rectifier.
Autotransformer.
Which is the most appropriate tool to cut into a plasterboard wall to insert a socket-outlet backbox?
Pad saw
Panel saw
Tenon saw
Junior hacksaw
Which type of conduit may be affected by UV rays from direct sunlight?
White rigid PVC
Black rigid PVC
Stainless steel
Galvanised steel
Which risk may be caused by leaving burrs within metallic conduit?
Increase corrosion
Increased eddy currents
Damage to cable insulation
Reduced mechanical strength
What type of cable support system would a crampet be used to secure in place?
Tray
Ladder
Conduit
Trunking
What is the minimum distance between cleats supporting an accessible horizontal steel wire armoured cable with an overall diameter of 12 mm?
350 mm.
400 mm.
450 mm.
550 mm.
What is the minimum number of bends required to be made to produce a bubble-set in straight conduit?
1.
2.
3.
4.
Which cable insulation material must not be used in direct contact with expanded polystyrene?
PVC
XLPE
Glass
Rubber
Which type of circuit would be most likely to contain an intermediate switch?
Shower
Lighting
Cooker
Alarm
What is the maximum number of 4 mm² single-core conductors that can be installed in one straight 3 m length of 20 mm galvanised conduit?
6
7
8
9
Which of the following would be the best PVC conduit temperature to assist the process of making a 90° bend?
0 °C
10 °C
60 °C
200 °C
What type of fixing is shown in Figure 5?
Anchor bolt
Channel nut
Masonry bolt
Spring toggle
What is the purpose of a catenary wire?
Drawing in cables into conduit
Providing an earth connection
Supporting overhead conductors
Connecting a computer system
Which type of cable would commonly use the type of connector shown in Figure 6?
CAT 5
Coaxial
Single-core
Twin and cpc
What is the maximum transmission voltage used on the UK super-grid?
132 000 V
275 000 V
400 000 V
660 000 V
Who is responsible for the meter tails prior to the electricity meter?
Local authority
Installation owner
Licencing authority
Network operator
What must as a minimum be provided at the origin of all single-phase installations?
Single-pole main switch
Double-pole main switch
Triple-pole main switch
Quadruple-pole main switch
What is the typically quoted maximum value of Zₑ for a TN-S earthing arrangement?
0.20 Ω
0.35 Ω
0.65 Ω
0.80 Ω
What is the earthing conductor connected to, at the origin of an installation forming part of a TN-C-S system?
An incoming water pipe.
The general mass of earth.
Lead sheath of the supply cable.
The incoming supply neutral point.
What type of protection is provided by an RCD?
Earth fault protection.
Overload protection.
Short circuit protection.
Basic protection.
Which is a method of providing Basic Protection as prescribed in BS 7671?
Bonding.
Earthing.
Barriers.
Fuses.
What is the purpose of main protective bonding?
To reduce the circuit Zₛ.
To provide equipotential.
To reduce the installation Zₑ.
To provide a fault path to earth.
What is the maximum disconnection time for a 32 A 230 V final circuit within a TN-S installation as given in BS 7671?
0.2 s
0.4 s
1 s
5 s
Which is an extraneous-conductive-part?
Metallic conduit system.
Metallic trunking system.
Metallic gas installation pipe.
Metallic case of a consumer unit.
What is the symbol for the total earth fault loop impedance path of a circuit?
Zₛ
R₁
R₂
Zₑ
Which item of metalwork would be earthed within an electrical installation in a factory?
Gas installation pipe.
Water installation pipe.
Metallic trunking system.
Lightning protection system.
What is the mV/A/m value for a 2.5 mm² multicore 70°C thermoplastic cable forming a single-phase circuit?
11
18
29
44
What is the actual length of a wall if it measures 200 mm on a drawing with a scale of 1:50?
0.1 m.
1.0 m.
10 m.
100 m.
Which accessory would be represented by the symbol in Figure 7?
Single-pole switch.
Double-pole switch.
Three-pole switch.
Four-pole switch.
What must be provided adjacent to a lathe in a machining workshop?
30 mA RCD.
Main switch.
Circuit breaker.
Emergency switch.
Which would be the most appropriate rating for a circuit breaker protecting a lighting circuit in a three-bedroom dwelling?
1 A
6 A
20 A
32 A
A 4 mm² 70°C thermoplastic insulated and sheathed flat cable with protective conductor is to be installed Reference Method C. What would be the maximum rating of a BS 3036 fuse providing overload protection for this cable?
5 A
15 A
20 A
30 A
What must be supplied to the client following the installation of a new circuit and an electric shower?
Electrical Installation Certificate.
Minor Works Certificate.
Electrical Installation Condition Report.
Periodic Inspection Report.
What would be the voltage drop for a 28 m 1.5 mm² single-phase circuit supplying a load of 13 A using 70°C thermoplastic insulated and sheathed flat cable with protective conductor?
16.0 V
11.5 V
10.6 V
6.9 V
