Mock Exams
In this section there are five mock test papers. These are only
meant to be a representation what your final exam might be.
As mentioned at the beginning, your final exam is comprised from
a database of 500 questions of which 30 or 60 questions will be
selected at random.
If you passed your 16
thEdition BS 7671 after June 2001, then you
will only need to do the 1 hour / 30 question test (2382-20).
Any electrician who qualified before June 2001 will have to do the
2 hour / 60 question test (2382-10).
Paper 1 is a 30 question mock exam. For this exam you need to
allow yourself 1 hour to complete it and to score 20 out of 30 to
pass (65%).
Papers 2 to 5 are 60 question mock exams. For these exams you
need to allow yourself 2 hours per paper. To pass, you will need to
score 39 out of 60, (65%).
All answers, and where to locate them within BS 7671:2008, can
be found in the answer section of this e-book.
REMEMBER you are allowed to take your BS 7671:2008 into the
exam, and within that book are ALL the answers to any of the
questions that may come up.
Below you can print off a blank answer sheet to fill in your
answers.
Answer Sheet
2382-20 TEST QUESTIONS – PAPER 1
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2382-10 TEST QUESTIONS – PAPER 4
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2382-10 TEST QUESTIONS – PAPER 5
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MOCK EXAM
2382-20 TEST QUESTIONS – PAPER 1
1. BS7671 applies to: a) aircraft
b) photovoltaic supplies c) distributors equipment
d) electrical equipment of machines 2. BS 7671 does not apply to:
a) railway traction equipment b) photovoltaic systems c) marinas
d) fairgrounds
3. Protection against electric shock under single fault conditions is: a) basic protection
b) fault protection c) additional protection d) supplementary protection
4. Which of the following would not be defined as a live part? a) neutral conductor
b) line conductor c) neutral bar d) PEN conductor
5. Every installation should be divided into circuits as necessary to avoid: a) fuse discrimination problems
b) hazards to minimise inconvenience in the event of a fault c) unauthorised interference with safety supplies
d) wiring impracticability
6. The protective measure ‘automatic disconnection of supply’:
a) is only permitted if the installation is under effective supervision b) is a method of reducing thermal effects
c) is a combination of basic and fault protection
7. The maximum disconnection time for a 16A final circuit having Uo 230V ac on a TN system is: a) 5 s b) 0.2 s c) 0.4 s d) 0.1 s
8. Where there is a danger of fire due to the nature of stored materials a motor with star – delta starting must be protected against excessive temperature:
a) in star b) in delta
c) in both star and delta d) only if 10 kw or more
9. In the event of failure of the provision for basic protection, additional protection may be provided by:
a) supplementary bonding
b) use of a time delay 100mA RCD
c) use of a RCD with l∆n not exceeding 30mA d) electrical separation
10. Which of the following is not a method of fault protection: a) placing out of reach
b) use of class II equipment c) earthing and bonding d) electrical separation
11. For a TT system where disconnection in the case of earth fault is achieved by RCD, the maximum disconnection time for a general socket in a domestic kitchen is:
a) 0.1 s b) 0.2 s c) 0.4 s d) 5 s
12. In the event of an earth fault on the HV side of a substation, the LV installation may be affected by:
a) power frequency fault currents b) power frequency stress voltages c) power current stresses
13. Connection of extraneous conductive parts to the MET of an installation forms part of the requirements for:
a) SELV
b) enclosures c) basic protection d) fault protection
14. Thermoplastic PVC T&E buried less than 50mm must be protected by:
a) MCB
b) cpc the same size as the P & N
c) 30mA RCD
d) disconnection time of 0.4 s
15. RCD installed for protection against fire must have a rating not exceeding:
a) 30 mA
b) 100 mA
c) 300 mA
d) 500 mA
16. Which of the following may not be used as an earth electrode: a) underground structural steel work
b) welded metal reinforcement c) water utility supply pipes d) earth plates
17. Socket outlets with a rating not exceeding 20A for general use by ordinary persons should be:
a) connected as a ring circuit b) connected as a radial circuit c) protected by a 30mA RCD d) protected by a 20A CB
18. Lighting installations in bus shelters must be protected by:
a) CCTV
b) double pole circuit breakers c) graffiti proof covers
19. Busbar trunking systems must comply with: a) BSEN 60439-2
b) BSEN 61534-1 c) BSEN 60898-7 d) BSEN 60309-2
20. The minimum acceptable value for insulation resistance in 230v supply is:
a) 0.25 MΩ b) 0.5 MΩ c) 1.0 MΩ d) 5.0 MΩ
21. Insulation resistance measured between line and neutral of a 230v domestic installation should not be less than:
a) 0.25 MΩ b) 0.5 MΩ c) 0.75 MΩ d) 1.0 MΩ
22. A PV generator and array junction box must have a warning label indicating that:
a) high voltage is present
b) parts inside may still be live following isolation c) PV array must be cleaned regularly
d) PV arrays are fragile
23. All circuits in a bathroom must have: a) protection by a 30mA RCD b) disconnection time of 5 s c) supplementary bonding d) protected by a CB
24. Electrical cables in Zone 1 of a fountain shall be protected against mechanical impact to:
a) AG1
b) AG2
c) AH2
25. On agricultural premises an RCD may be used for protection against fire providing that the rating of the RCD does not exceed:
a) 30 mA
b) 150 mA
c) 300 mA
d) 500 mA
26. Any luminaries of lighting chains used at a circus must be firmly fixed when at a height less than:
a) 1 m b) 1.5 m c) 2 m d) 2.5 m
27. In a bathroom the protective measure of obstacles is: a) allowed in all zones
b) allowed in zones 1 & 2 c) allowed in zone 2 only d) not allowed
28. Where a TN system of earthing is used in a marina the final circuits for the supply of a pleasure craft must not include:
a) any earth conductors b) a PEN conductor c) any RCD’s
d) protective devices
29. For a 100 mA non-delay RCD to BSEN 61008 the residual test currents and maximum permitted disconnection times are:
a) 100 mA 300ms 500 mA 40ms
b) 100 mA 130ms 1500 mA 150ms
c) 100 mA 0ms 100 mA 40ms
d) 100 mA 400ms 500 mA 50ms
30. Flat T & E cable clipped direct to a ceiling joist where thermal insulation exceeds 100mm thickness is installation method:
a) 101 b) 100 c) 3
2 HOUR
MOCK EXAM
2382-10 TEST QUESTIONS – PAPER 2
1. To which of the following electrical installations does the IEE Regulations NOT apply?
a) agricultural and horticultural premises b) construction sites
c) systems for transmission of energy to the public d) caravans and their sites
2. The BS 7671 relates to permanent and temporary installations for: a) equipment on board ships
b) aircraft equipment c) construction sites
d) electric traction equipment
3. An a.c. voltage of 90 V between conductors is classified as: a) extra-low voltage
b) low voltage
c) safety extra-low voltage d) reduced low voltage
4. Which one of the following types of installation is NOT included in the special installations recognised by the IEE Wiring Regulations?
a) swimming pools b) petrol filling stations c) agricultural
d) saunas
5. The MAXIMUM accessible distance that it should be assumed a person can reach when standing on a surface is:
a) 0.75 m b) 1.25 m c) 2.50 m d) 3.00 m
6. BS 7671 requires that the designer of a new installation shall: a) have at least three years experience
b) recommend future inspection and testing c) complete a periodic test report
7. Non-sheathed cables for fixed wiring, other than protective conductors, should always be installed in:
a) dry conditions b) trenches
c) conduit or trunking d) sub-zero temperatures
8. A final circuit is the wiring between the: a) main cut-out and the energy meter b) main switch and the distribution board
c) distribution board and current-using equipment
d) consumer’s main earth terminal and circuit protective device
9. The prospective short circuit current at the origin of the consumer’s installation must be taken into account when:
a) estimating the external earth loop impedance b) supplying diversity factor for the installation c) selecting the system of earthing for the supply
d) selecting the type of overcurrent protective device to be installed 10. A system is defined as:
a) the kWh meter and an installation b) the distribution cables to an installation c) the consumer’s terminals of an installation d) a single source of energy and an installation
11. The total number of socket-outlets that may be connected to a fused spur is:
a) one twin or one single socket – outlet
b) equal to the total number of socket – outlets on the ring c) equal to half the number of socket – outlets on the ring d) unlimited depending upon the load
12. Residual current circuit breakers shall NOT be used on a TN system where a circuit incorporates:
a) protective conductors b) exposed conductive parts c) earthing conductors d) PEN conductors
13. Which one of the following is a method of providing fault protection? a) placing out of reach
b) double insulation c) protection by obstacles d) insulation of live parts
14. In addition to regular maintenance of an installation, which one of the following is NOT an essential requirement?
a) periodic inspection and testing may be readily and safely carried out
b) the name and address of the contractor is permanently displayed adjacent to the main intake position
c) the reliability of the equipment is sustained d) protective measures for safety remain effective
15. Where separated extra-low voltage is used to provide basic protection and fault protection, the nominal voltage shall NOT exceed:
a) 12 V a.c. b) 25 V a.c c) 50 V a.c. d) 110 V a.c.
16. Overload current is defined as the overcurrent:
a) that causes protective devices to operate of correctly b) occurring in a circuit which is electrically sound
c) resulting from a fault of negligible impedance between live conductors of different phases
d) flowing in a line conductor when in contact with exposed conductive parts
17. The IEE Regulations are designed to provide: a) instructions for untrained persons
b) safety especially from fire, shock and burns c) a detailed specification
d) instructions for every circumstance in an installation
18. Which one of the following is not permitted as a means of isolation in a circuit?
a) double-pole switch fuse b) 13 A plug and socket c) semi-conductor device d) linked switch
19. When a line conductor comes in contact with the neutral conductor, the type of fault is called:
a) a short circuit fault b) an earth fault c) an overload fault d) an open circuit fault
20. A means of isolation must be provided in an electrical installation. This is required to be:
a) clearly identified
b) always placed next to the equipment it isolates c) automatic in operation
d) available for emergency switching
21 Which one of the arrangements complies with the IEE Wiring Regulations?
a) the fire fighter’s switch is fixed 4 m above the ground and the off at the top
b) the fire fighter’s switch is coloured red and the off position is at the bottom
c) The fire fighter’s switch is coloured red and fixed 2.5 m above the floor
d) The fire fighter’s switch is fixed 2 m above the floor and off at the bottom
22. A fire fighter’s emergency switch should be provided for: a) emergency lighting systems operating at low voltage b) interior low-voltage discharge lighting installation
c) exterior discharge lighting installations exceeding low voltage d) multi-storey office block fire alarm circuits operating above low
voltage
23. The three general categories of external influence are environment, utilisation and:
a) the number and type of live conductors b) construction of building
c) method of installation
24. BS 7671 details the requirements of devices for emergency switching. Which of the following devices would NOT satisfy these requirements? a) an emergency stop button which breaks the control circuit of a
contactor
b) a switch which breaks the control circuit of a contactor c) a 32 A plug and socket outlet
d) a switch which breaks all live conductors
25. Which one of the following is required to be considered by BS 7671 when assessing the general characteristics of an electrical installation? a) the standard of electricians working on site
b) diversity
c) switchgear rating d) maintainability
26. The following factors are used when calculating the minimum size of cable:
ln = nominal current of protective device
Cg = grouping correction factor
Ca = ambient temperature correction factor
Ci = thermal insulation correction factor
A circuit protected by a circuit breaker type B to BS EN 60898 would be supplied by a cable with a current carrying capacity not less than: a) i g a n C x C C x I b) a i g n C C x C x I c) i g a n C x C x C I d) Ca x Cg x Ci x In
27. When calculating the voltage drop in an installation which one of the following should be taken into account?
a) the cable current carrying capacity b) the operating current of the fuse c) the current rating of the fuse d) the circuit design current
28. Which one of the following is not considered when calculating the minimum current carrying capacity of live conductors of a cable?
a) ambient temperature b) grouping
c) type of protective device
d) the maximum permitted volt drop
29. For single circuit cable selection purposes the correction factors must be applied to the:
a) prospective short circuit current b) current carrying capacity of the cable c) current rating of the protective device d) the earth fault current of the circuit 30. The classification code for high wind is:
a) AS3
b) AR3
c) AP3
d) AN3
31. Rating factors are applied to the fuse rating of a circuit to determine the minimum current-carrying capacity of cables. A rating factor of 1 is used when a circuit is wired in 70º C thermoplastic insulated cable and operating in an ambient temperature of:
a) 25º C b) 20º C c) 30º C d) 35º C
32. Which one of the following is not recognised by BS 7671:2008 as the sole means of earthing an installation?
a) metallic sheath of cables
b) metal bars embedded in the building foundations c) metallic rod driven into the ground
d) gas and water supply pipes
33. A BS 1361 fuse, rated at 45 A, is carrying a fault current of 240A, the protective device should operate in:
a) 0.4 s b) 8.0 s c) 300 s d) 5.0 s
34. The maximum permissible earth fault loop impedance on a TN system for a ring final circuit protected by a 30 A BS 1361 fuse is:
a) 1.15Ω
b) 1.2Ω
c) 1.92Ω d) 2.76Ω
35. The wording of a permanent warning notice fixed at the point of connection of an earthing conductor to an earth electrode is:
a) Earth Connection – Do Not Remove b) Do Not Remove This Connection c) Electrical Earth Connection – Danger
d) Safety Electrical Connection – Do Not Remove
36. Which one of the following sources does not comply with BS 7671 as a SELV system?
a) a safely isolating transformer to BS EN 61558
b) a motor generator with windings providing equivalent isolation to that of a safety isolating transformer
c) a centre tapped transformer giving 55 V to earth d) a battery system operating at extra low voltage
37. The minimum size of a copper earthing conductor buried in the ground,
NOT mechanically protected and NOT protected against corrosion is:
a) 10 mm²
b) 16 mm²
c) 25 mm²
d) 50 mm²
38. When calculating the minimum cross-sectional area of a protective conductor, the following information is available:
Fault current = 650 A
Operating time of protective device = 0.35 sec Constant, k, for protective conductor material = 115 The selected size of the protective conductor should be: a) 2.5 mm²
b) 4.0 mm² c) 6.0 mm²
39. When a residual current device protects a socket outlet in a domestic garage it must operate when:
a) an earth fault on the garage lighting circuit occurs
b) the protective conductor in a flexible cord to a lawn mower breaks
c) someone comes in direct contact with an exposed line conductor and earth
d) someone comes in contact with exposed earth metalwork
40. Where an auto-transformer is connected to a single-phase supply (phase and neutral) the common terminal of the winding should be connected to the:
a) neutral conductor b) phase conductor
c) circuit protective conductor d) main earthing terminal
41. Circuit cables required to carry the starting, accelerating and load currents of motors shall have a current rating not less than:
a) full-load b) 1.5 x full-load c) 6 x full-load d) 10 x full load
42. As part of a detailed inspection which of the following must be checked?
a) the presence of fire barriers and protection against thermal effects
b) the prospective short circuit current at the origin of the installation
c) the maximum permissible voltage drop d) the manufacturer’s name of any RCD fitted
43. Which of the following items should be included for checking during the initial verification of an installation:
a) site works orders and alterations b) presence of diagrams and instructions c) minutes of all site meetings
44. One item that should be included on charts and diagrams made available to the person carrying out an inspection and test is:
a) all isolation and switching arrangements b) the location details of portable equipment c) the total number of outlets in the installation d) the details of the original contract arrangements
45. Which on of the following insulation resistance test results, meets the minimum acceptable value for an installation with a 400 V supply? a) 5.0 MΩ
b) 0.25 MΩ c) 0.5 MΩ d) 1.0 MΩ
46. The test voltage required to carry out an insulation resistance test on an installation with a nominal supply voltage of 400 V is:
a) 250 V dc b) 400 V dc c) 500 V dc d) 1000 V dc
47. An earth fault loop impedance test determines the actual value of: a) Zs
b) Ze
c) R1
d) R2
48. Electrical installation certificates should be signed by those responsible for the:
a) inspection and testing only b) installation work only c) main contract
d) design, construction and inspection testing
49. The result and extent of a Periodic Inspection and Test shall be recorded and given to the:
a) original installer
b) person ordering the inspection c) representative of the supplier d) installation designer
50. The following tests are to be carried out on a new installation 1 insulation resistance
2 continuity of ring final circuit 3 continuity of protective conductors 4 earth loop impedance
5 polarity
The correct order of carrying out the tests is: a) 1, 2, 3, 4, 5
b) 3, 2, 1, 5, 4 c) 2, 3, 5, 1, 4 d) 5, 4, 1, 2, 3
51. One reason for carrying out a polarity test is: a) lighting switches work
b) the outer screwed contact is connected to the phase conductor c) sockets are switched
d) fuses are fitted in the phase conductor
52. When carrying out a continuity of circuit protective conductor test, it is recommended that a test instrument operates at:
a) 500 V and delivers a short circuit current of 100 mA b) 50 V and delivers a short circuit current of 200 mA c) 20 V and delivers a short circuit current of 100 mA d) 20 V and delivers a short circuit current of 200 mA
53. One of the purposes of an inspection prior to initial testing of an installation, is to verify that the installed equipment is:
a) connected to the supply and energised b) not visibly damaged
c) functioning safely when energised
d) exceeds the minimum insulation resistance value
54. Electrical equipment installed above a swimming pool diving board should not be fixed at a height less than:
a) 1.5 m b) 2.0 m c) 2.5 m d) 3.0 m
55. Which of the following may be installed inside a hot air sauna? a) a socket outlet fed from an SELV supply source
b) a ceiling mounted cord operated light switch c) a thermostat mounted on the sauna
d) any equipment and accessories to IP24 56. Construction site special regulations apply to:
a) all site offices b) earthworks c) site canteens d) site toilets
57. In agricultural premises, an RCD may be used for protection against fire providing the operating current does not exceed:
a) 30 mA
b) 150 mA
c) 300 mA
d) 500 mA
58. The minimum cross-sectional area of any conductor in a caravan is: a) 1.5 mm²
b) 2.5 mm² c) 4.0 mm² d) 6.0 mm²
59. The maximum permissible height for a caravan inlet is: a) 0.5 m
b) 1 m c) 1.5 m d) 1.8 m
60. One method acceptable to the IEE Regulations for providing fault protection on circuits feeding street furniture is by:
a) a non-conducting location b) earth free equipotential bonding c) automatic disconnection of supply d) electrical separation
PAPER 3
MOCK EXAM
2382-10 TEST QUESTIONS- Paper 3
1. BS7671 relates to electrical installations in and around buildings but excludes:
a) agricultural and horticultural premises b) construction sites
c) electrical equipment on board ships d) caravans
2. Parts 3 to 7 of BS 7671 covers in detail methods and practices which meets the requirements of:
a) Chapter 11 b) Chapter 12 c) Chapter 13 d) Part 2
3. The IEE Regulations recognises that in electrical installations there is a risk of injury from:
a) dangerous chemicals b) shock currents
c) high winds d) asbestos
4. Which one of the following types of installations is NOT within the statutory control of an authoritative body?
a) petrol stations b) caravan site c) theatre d) domestic
5. The type of building construction in which an installation is to be carried out may affect the design and safe operation of the installation. This effect is called:
a) the nature of the supply b) compatibility
c) installation arrangements d) an external influence
6. Which one of the following is not classed as a Band 1 voltage circuit? a) a bell circuit
b) a 230 V lighting circuit c) a SELV circuit
d) a 25 V signalling circuit
7. Which one of the following external influences requires an increase in the current ratings of cables above those normally required?
a) the presence of light dust b) low ambient temperature c) high wind
d) high ambient temperature
8. One of the general categories of external influences is: a) earthing arrangements
b) environment
c) method of installation d) nature of supply
9. Where the circuit protective conductor is not a metal cable covering or metal trunking and conduit, the c.p.c for a ring final circuit must:
a) be run in the form of a ring having both ends connected to the earthing terminal
b) have a cross-sectional area not less than that of the live conductors of the ring
c) be made of aluminium
d) be wired in single-core cable 10. A TN-C-S system has:
a) the neutral and earth functions combined in a single conductor in part of the system
b) the exposed conductive parts of an installation connected to an earth electrode which is independent to the source
c) a separate protective conductor connecting the source earth to the consumers main earth terminal
d) the neutral and protective conductors are combined throughout the system
11. Installations should be arranged so as to avoid danger and minimise inconvenience in the event of a fault and facilitate safe operation, inspection, testing and maintenance. One method of complying with this is to:
a) connect all circuits on the radial principle b) fit an RCD at the main intake position c) divide the installation into separate circuits d) divide the installation into lighting and power
12. The prospective short circuit current at the origin of the consumer’s installation must be taken into account when:
a) assessing the value of the external earth loop impedance
b) selecting the number of ways required for the main distribution board
c) assessing the methods to be used to provide basic protection d) selecting the type of overcurrent protective device to be installed 13. A two-storey domestic dwelling should have a minimum of two lighting
circuits in order to:
a) use 10 A circuit breakers for the lighting circuits b) reduce the load on the consumer unit
c) avoid danger in the event of a fault
d) enable a greater variety of luminaires to be used
14. With reference to the general characteristics of an electrical installation, the maximum demand should be:
a) determined by the supply company b) calculated from the installation drawings c) obtained from the architect
d) assessed, taking diversity into account
15. The requirements for both basic and fault protection can be provided by SELV. One suitable source of SELV would be a:
a) 50 V storage battery b) 230 V diesel generator
c) 230/110 V single phase generator d) 230/50 V auto-transformer
16. Residual current circuit breakers shall NOT be used on a TN system where a circuit incorporates:
a) fuses
b) exposed conductive parts c) socket outlets
d PEN conductors
17. A component of a support system consisting of regularly spaced elements which mechanically retains a cable is defined as a cable: a) bracket
b) ladder c) cleat d) tray
18. SELV can be used as a means to meet the requirements of both basic and fault protection. In such cases the nominal voltage must not exceed:
a) 12 V ac b) 25 V ac c) 50 V ac d) 110 V ac
19. Which one of the following classifications of external influences would be appropriate for an item of electrical equipment installed where it would be subject to an atmosphere where heavy dust is present?
a) AE1
b) BC1
c) AE6
d) AG1
20. The fault current due to an earth fault of negligible impedance in a 400 V, three phase, four wire circuit having an earth loop impedance of 0.3 ohms, is:
a) 1383 A b) 767 A c) 124.5A
21. A section of a factory requires urgent repairs to a machine. The type of switching provided to allow this work to proceed would be switching for: a) mechanical movement
b) mechanical maintenance c) emergency
d) safe operation
22. The correct classifications of an external influence consisting of light dust is:
a) AC2
b) BA2
c) AE4
d) AH3
23. lz is the current rating of a circuit conductor. The requirements for
overload current protection are fulfilled when: a) lb = 22A, ln = 25A, lz = 18A
b) lb = 18A, ln – 15A, lz = 15A
c) lb = 9A, ln = 15A, lz = 17A
d) lb = 8A, ln = 10A, lz = 8A
24. Where the overcurrent device is intended to afford protection against overload, l2 must NOT exceed lz times:
a) 0.725 b) 1.45 c) 1.8 d) 5
25. A fault current caused by the line and neutral conductors to come in contact with each other is referred to as:
a) an earth fault b) an overload fault c) a short circuit fault d) an open circuit fault
26. A 230 V single-phase circuit supplying a pump motor is protected by a 20 A circuit breaker to BS EN 60898 type B. The minimum value of fault current to ensure compliance with thermal and shock constraints is:
a) 20 A b) 100 A c) 150 A d) 200 A
27. Where a means of isolation is provided in an electrical installation, the means must be:
a) clearly labelled
b) always adjacent to equipment c) available for emergency switching d) automatic in operation
28. Overload current is an overcurrent occurring in a circuit: a) due to an earth fault
b) due to a short-circuit fault c) that is electrically sound d) that is not fully loaded
29. The designer/installer of a ceiling heating system must provide a plan for the installation. Information NOT required on the plan would be the: a) number of rooms within the installation
b) number of heating units installed c) position of the junction boxes d) leakage capacitance
30. When 13 A socket outlets are wired from a fused spur using 70º thermoplastic insulated cable with copper conductors, the minimum conductor size permissible is:
a) 1.0 mm² b) 1.5 mm² c) 2.5 mm² d) 4.0 mm²
31. The correction factor for a cable surrounded by thermal insulation for a length of 200 mm is:
a) 0.5 b) 0.63 c) 0.75 d) 1.0
32. When selecting a cable for a single circuit installation, correction factors are to be used and applied to the:
a) total current taken by the installation b) current-carrying capacity of the cable c) design current of the circuit
33. Where protection against overload is provided by a semi-enclosed fuse to BS 3036, the current rating of the cable must be at least:
a) 0.725 times the current rating of the fuse
b) the nominal current rating of the fuse divided by 0.725 c) the same rating as the design current of the circuit d) 0.725 times the design current of the circuit
34. Correct co-ordination between conductors and overcurrent protection device is achieved when:
a) ln is not less than the design current lb
b) ln exceeds the lowest current carrying capacity lz
c) the current causing effective operation (l2) exceeds 1.45 l2
d) lb is greater than lz
35. In order to calculate the minimum value of the cross-sectional area of a protective conductor the following information is available
Fault current = 300 A
Operating time of the protective device = 0.6 s Constant k, for protective conductor material = 115
The minimum, cross-sectional area of the protective conductor should be:
a) 2.5 mm² b) 1.5 mm² c) 6.0 mm² d) 4.0 mm²
36. The rating factor to be applied for eight equally loaded circuits grouped together in conduit is:
a) 0.54 b) 0.52 c) 0.50 d) 0.71
37. A circuit is protected by a 10 A BS 3036 semi-enclosed (rewireable) fuse. The minimum permissible current rating (lz) of a conductor
protected by this fuse would be: a) 7.25 A
b) 10 A c) 13.8 A d) 20 A
38. An office installation is connected to a TT system and earth fault protection is provided by a residual current device. The product of the rated residual operating current of the device and the earth electrode resistance plus the protective conductor’s resistance connecting it to the exposed conductive parts shall not exceed:
a) 0.5 V b) 230 V c) 50 V d) 500 V
39. A circuit is connected to a TN system, the maximum permissible earth fault loop impedance (Zs) for a 32 A socket outlet circuit protected by a
BS 88 fuse is: a) 1.04Ω b) 1.09Ω c) 1.44Ω d) 0.92Ω
40. Regulation 434.5.2 gives the maximum time which may be permitted for a fault to be maintained without damaging the conductors. Assume a prospective fault current of 1000 A with a copper 25 mm² cable with 70º C thermoplastic insulation. The clearance time (t) is:
a) 7.2 s b) 8.2 s c) 5 s d) 0.4 s
41. The purpose of having equipotential bonding conductors connected to the other services as close as practicable to their entry into the premises is to:
a) ensure that earth leakage is minimised
b) ensure that the maximum current will flow to earth under fault conditions
c) reduce the chance of shock risk within the premises
d) reduce the chance of electrolytic corrosion between metal sheath of cable and metal pipes
42. Where practicable main equipotential bonding to the gas services in a building should be made:
a) within 6 m of the meter on the supply side b) outside the building
c) within 600 mm of the meter on the supply side d) within 600 mm of the meter on the consumer’s side
43. Heating cables laid directly in soil, roads or building structures must be installed so that they are:
a) at least 1 m below the surface
b) fed only from an extra-low voltage supply
c) completely embedded in the substance which they are intended to heat
d) operated at 5º C
44. For circuits of TN or TT systems, the outer contact of Edison type screw lamp holders must be connected to the:
a) phase conductor b) earthing conductor c) neutral conductor d) protective conductor
45. The temperature limit for non-metallic equipment which is intended to be touched but not hand held is:
a) 55º C b) 65º C c) 70º C
d) 80ºC
46. The correct grouping factor for 6 circuits of three conductors per circuit, run in the same conduit is:
a) 0.45 b) 0.54 c) 0.57 d) 0.6
47. Which one of the following does NOT determine the frequency of periodic inspection and testing of an installation?
a) formal qualifications of the inspection and test staff b) the type of installation
c) frequency of maintenance
d) any external influence to which it is subjected
48. Every new installation on completion and before being energised must FIRST be:
a) subjected to a detailed inspection
b) tested for continuity of ring circuit conductors c) tested for continuity of protective conductors d) given a test for insulation resistance
49. Which one of the following items should be included for checking during the initial verification of an installation?
a) site works orders and alterations
b) presence of all diagrams and instructions c) electrical contractor’s site diary
d) all variations of contract
50. Which one of the following British Standards covers residual current devices?
a) BS EN 61008 b) BS EN 60898 c) BS EN 60947 d) BS EN 60742
51. For an insulation resistance test on a 230 V ac installation containing surge protected socket-outlets, the value of the test voltage may be: a) 460 dc
b) 500 dc c) 250 dc d) 1000 dc
52. When a 30 mA residual current device used to provide additional protection is tested at a residual current of 150 mA, the device should open in no more than:
a) 40 ms b) 200 ms c) 0.4s d) 5 s
53. The minimum value of insulation resistance when measured at the consumer unit of a 230 V domestic installation is:
a) 0.25 MΩ b) 0.5 MΩ c) 1.0 MΩ d) 5.0 MΩ
54. The results of periodic inspection and testing should be recorded on a report and signed by the:
a) person ordering the inspection b) design engineer
c) site engineer
55. Equipment fitted in Zone 1 of a bathroom must: a) be rated at a voltage not exceeding 12 V b) have a minimum IP rating of IPX5
c) have a minimum IP rating of IPX4 d) be fed from a plug and socket outlet
56. In agricultural premises, an RCD may be used for protection against fire providing the operating current does not exceed:
a) 30 mA
b) 100 mA
c) 300 mA
d) 500 mA
57. For all caravans using a mains electricity supply, an instruction notice must be fixed:
a) at or near the main distribution point
b) under the cover of the caravan electricity inlet box
c) near the main electrical isolating switch inside the caravan d) on the inside of the main door of the caravan
58. In a swimming pool which of the following protective measures is NOT applicable to equipment installed in Zone 2?
a) protection by earth free local equipotential bonding b) individual protection by electrical separation
c) SELV
d) protection by an RCD in accordance with Regulation 415.1.1 59. Which one of the following may be installed inside Zone 1 of a hot air
sauna?
a) a ceiling mounted cord operated light switch b) a shaver socket to BS 3535
c) a thermostat attached to the side of the sauna d) any equipment to IP2X
60. With regards to a transportable unit, a notice fixed in a prominent position on the unit need not display:
a) the frequency of the supply b) the type of supply
c) maximum power requirement d) voltage rating of the unit
PAPER 4
MOCK EXAM
2382-10 Test Questions – Paper 4
1 Particular requirements are included in BS 7671 for electrical installations of:
a) life installation covered by BS 5655 b) equipment of fixed offshore installations c) distributors equipment
d) locations containing bath or shower
2. Which one of the following types of installation is NOT included in the special installations recognised by BS 7671
a) swimming pools b) petrol filling stations c) agricultural
d) saunas
3. Which one of the following sets of regulations is non-statutory? a) Electricity Safety, Quality and Continuity Regulations b) Electricity at Work Regulations
c) Building Standards Regulations
d) BS 7671 Requirements for Electrical Installations 4. A d.c. voltage of 125 V between conductors is classified as:
a) extra-low voltage b) low voltage
c) reduced low voltage
d) SELV
5. The type of system known as PME is also referred to as:
a) TN-S
b) TN-C
c) TN-C-S
d) IT
6. A circuit protective conductor connects:
a) a gas pipe to the main earthing terminal
b) a water pipe to the earth terminal of a switch in a bathroom c) the main earthing terminal to the earth terminal of a
socket-outlet
7. An external influence categorized as AG1 applies to a: a) quarry
b) factory c) house d) workshop
8. A building constructed solely of wood would have an external influence category of:
a) CA1
b) CA2
c) CA3
d) CA4
9. A fire fighter’s emergency switch should be provided for: a) factory low-voltage burglar alarm systems
b) interior low-voltage discharge lighting installations
c) exterior discharge lighting installations exceeding low-voltage d) factory fire alarm circuits operating at low-voltage
10. The protective conductor used within a final circuit has high protective conductor currents in excess of 10 mA when supplying more than one item of electrical equipment. The minimal cross-sectional area may be 4 mm², provided that:
a) additional protection from the use of a residual current device is present
b) the protective conductor has additional mechanical protection c) individual items of equipment are supplied through an isolating
transformer
d) the protective conductor is in the form of a complete ring
11. Installations should be arranged so as to avoid hazards in the event of a fault, and to facilitate safe operation, inspection, testing and maintenance. One method of complying with this is to:
a) connect all circuits on the radial principle b) connect all circuits on the ring principle c) divide the installation into separate circuits d) divide the installation into bands of circuits
12. A domestic 30A radial final circuit is used to supply BS 1363 socket outlets. If the floor area to be served is 55m², the rating of the protective device and the live conductor’s csa must not be less than: a) 20A and 4 mm²
b) 30A and 2.5 mm² c) 20A and 2.5 mm² d) 30A and 4 mm²
13. Which one of the following is not a characteristic of the supply? a) nominal voltage
b) frequency
c) earth loop impedance Ze
d) emergency switching
14. The number and type of live conductors of a new electrical supply to a building may be determined:
a) by enquiry to the local council offices b) after consultation with the local distributor c) by reference to BS 7671
d) by reference to the Electricity, Safety, Quality and Continuity Regulations
15. Basic protection protects persons and/or livestock from contact with: a) Class II enclosures
b) extra-low voltage terminals
c) exposed conductive parts made live by a fault d) live parts
16. The requirements regarding basic protection have not been applied if livestock comes into contact with:
a) exposed conductive parts made live by a fault b) an exposed terminal within a faulty enclosure c) a protective conductor carrying fault current
d) extraneous conductive parts made live by an earth fault 17. One method of providing basic protection is by:
a) earth free local equipotential bonding b) electrical separation
c) automatic disconnection of supply d) barriers or enclosures
18. A piece of electrical equipment having a protective conductor current of 15 mA is to be connected to the supply by means of a 16A plug and socket outlet complying with BS EN 60309-2. The cross sectional area of the protective conductor of the associated flexible cable shall not be less than:
a) 1.00mm²
b) 1.5mm²
c) 2.5mm²
d) 4mm²
19. The maximum time (t) in seconds for the clearance of each and short circuit faults can be found from:
2 2 2 I S k t = Given that k = 115 s = 95 I = 16000 t = time in seconds The value of t is:
a) 0.466s b) 0.683s c) 0.745s d) 0.826s
20. The temperature limit for non-metallic equipment which is intended to be touched but not hand-held is:
a) 55ºC
b) 65ºC
c) 70ºC
d) 80ºC
21. The prospective fault current at the origin of an electrical installation must be taken into account when:
a) estimating the external earth fault loop impedance b) applying diversity to the installation
c) assessing the earthing arrangement
22. Omission of devices for protection against overload is NOT permitted for:
a) secondary circuits of current transformers b) circuits which supply fire extinguishing devices c) exciter circuits of rotating machines
d) circuits which supply emergency lighting
23. The nominal rating of an overcurrent protective device should be: a) not less than the design current
b) greater than the current carrying capacity of the conductors c) 1.45 times the load current
d) equal to the prospective short-circuit current
24. The means of isolation for a particular item of equipment may be installed in a position remote from that equipment, providing that it: a) can be locked in the off position using a lock and key common to
all other such isolators
b) can be locked in the off position using a lock and key that are unique to that isolator
c) is located so as to be in full view of persons working on the equipment
d) is manually operated and a visual display is located next to the equipment
25. A firefighter’s switch should be installed at not more than: a) 2.75m from the ground and the ‘off’ position at the top
b) 2m from the ground and the ‘off’ position at the bottom and coloured red
c) 2.75m from the ground and the ‘off’ position at the bottom
d) 2.75m from the ground and the ‘on’ position at the top and coloured red
26. Where the nominal voltage of an installation is 230V, the required minimum impulse withstand voltage for Category II equipment for overvoltage protection is:
a) 1.5kV b) 2.5kV c) 4.0kV d) 6.0kV
27. In a location where a risk of danger from fire exists due to manufacture or storage of combustible materials, enclosures of heaters shall not attain a surface temperature under normal working conditions exceeding:
a) 70ºC
b) 90ºC
c) 100ºC d) 115ºC
28. For a.c., the preferred frequencies which are taken into account in BS 7671 are:
a) 25 Hz, 50 Hz and 60 Hz b) 50 Hz, 60 Hz and 400 Hz c) 25 Hz, 50 Hz and 250 Hz d) 50 Hz, 100 Hz and 400 Hz
29. Which one of the following external influences requires an increase in the current ratings of cables above those normally required?
a) possible vertically falling drops of water b) low ambient temperature
c) severe mechanical vibration d) high ambient temperature
30. To prevent circulating eddy currents (an electromagnetic effect) in steel conduit, trunking or cable armouring:
a) only d.c. must be used
b) line and neutral conductors are to be kept separate c) the enclosures should be solidly earthed
d) all live conductors of a circuit must be contained in the same enclosure
31. It is required that all circuits in a barn on an agricultural installation be protected by an RCD. The maximum rating (l∆n) for a circuit protected
by a 40A BS 88 protective device should not exceed: a) 30 mA
b) 100 mA
c) 300 mA
32. In agricultural premises in locations where tractors are used, which one of the following methods of installation shall NOT be applied:
a) cables shall be buried at a depth of at least 0.6m with additional protection
b) cables in arable ground shall be buried at a depth of at least 1m c) self supporting suspension cables at a height of at least 6m d) self supporting suspension cables at a height in excess of that
accessible by rodents
33. A permanent warning notice must be fixed at or near the point of connection of every earthing conductor to an earth electrode. This notice must bear the words:
a) Earth Bonding Connection, Do Not Remove b) Safety Bonding Connection, Do Not Remove c) Earth Electrical Connection, Do Not Remove d) Safety Electrical Connection, Do Not Remove 34. Overcurrent protection may be provided by a:
a) linked switch
b) residual current device c) disconnector
d) circuit breaker
35. Where ADS is the means of providing fault protection and a 20 A type B circuit breaker to BS EN 60898 is used, the maximum earth fault loop impedance is:
a) 0.37Ω b) 1.15Ω
c) 2.3Ω
d) 2.87Ω
36. Which one of the following is excluded as a protective earth electrode? a) underground structural metalwork embedded in foundations b) welded metal reinforcement of concrete embedded in the earth c) earth plates
d) metalwork of public water services
37. A copper earthing conductor not mechanically protected and not protected against corrosion is buried in soil. The minimum size of the earthing conductor is:
a) 4mm²
b) 16mm²
c) 25mm²
38. By employing an RCD protected socket-outlet to supply a Class II portable tool, the user is:
a) protected against an earth fault in the windings of the tool
b) protected against breakage of the protective conductor of the flexible cable
c) provided with additional fault protection against contact with a live conductor exposed by carelessness of the user
d) unable to operate the tool until the earthing circuit is complete and monitored
39. A 13A socket-outlet supplies mobile equipment for use outdoors. Additional protection should be provided by means of a:
a) general purpose fuse b) circuit breaker
c) residual current device d) class II equipment enclosure
40. In order to prevent the spread of fire where a wiring system passes through elements of building structures, any holes must be sealed around the cables. Which of the following is NOT a requirement for such sealing materials?
a) it shall be compatible with the material of the wiring system b) it shall prevent thermal movement of the wiring system
c) it shall be of adequate mechanical stability to withstand the stresses which may arise
d) it shall resist relevant external influences to the same degree as the wiring system
41. Where an autotransformer is used for step-up purposes: a) a single-pole switch can be used
b) a linked switch breaking all live conductors must be used c) no controlling switch is required
d) only a fuse is required
42. When installing socket outlets which will be mounted vertically on a wall or working surface, they should be:
a) shuttered and suitable for a.c. and complying with BS 1363 b) mounted 50mm from the floor level or working surface
c) mounted so the flexible cord and plug top can be withdrawn or inserted without mechanical damage
d) mounted so that the flexible cord and plug are 50mm from floor or working surface level
43. Any circuit or equipment vulnerable to a particular test should be identified by:
a) the provision of a legible diagram, chart or table prior to testing b) a visual inspection prior to testing
c) the manufacturer’s warning notice on the equipment d) the inventory for the building being tested
44. Which one of the following tests is carried out after the supply is connected?
a) insulation resistance
b) continuity of protective conductors c) continuity of ring final circuit conductors d) effectiveness of an RCD
45. The purpose of the inspection conducted prior to testing an installation is to verify that:
a) all ring final circuit connections are correct b) equipment is not damaged or defective c) only British Standard equipment is installed
d) all electrical cables and conduits are pointed orange for identification
46. When testing a 230V installation, the minimum value of insulation resistance is:
a) 0.5Ω
b) 1Ω
c) 0.5MΩ
d) 1MΩ
47. No alteration shall be made to an existing installation unless the: a) electricity supplier has been informed
b) local authority has been informed
c) it is established that the alteration will not impair the safety of the existing installation
d) existing equipment meets BS and BS EN standards
48. The inspecting and testing required during a periodic inspection should be recorded on a Periodic Inspection Report and carried out by:
a) the person ordering the inspection b) a design engineer
c) a site engineer
49. Which one of the following factors does not affect the frequency of periodic inspection?
a) type of installation
b) installation use and operation c) frequency of maintenance d) supplies for safety services
50. Which one of the following numbers is the correct grouping factor for six circuits installed as method B?
a) 0.45 b) 0.55 c) 0.57 d) 0.69
51. The reference for the installation method that has multi-core cables having a non metallic sheath, in surface mounted conduit is:
a) E
b) B
c) F
d) G
52. Which one of the following classifications of external influences would be appropriate for an item of electrical equipment installed where it would be subject to ‘splashes of water’?
a) AB
b) BC1
c) AD4
d) AG1
53. In rooms containing a bath or shower, the measures of protection by obstacles and placing out of reach are:
a) permitted in zones 1 and 2 only b) not permitted in any circumstance c) permitted for SELV circuits only d) not permitted except for luminaries
54. The nominal supply voltage on temporary installations in shows and stands shall not exceed 230/400 V ac, or
a) 110 V dc b) 230 V dc c) 240 V dc d) 500 V dc
55. In a conduit system on an agricultural installation where livestock are kept, the external influence shall be classified as:
a) AF4
b) AG3
c) AF3
d) AG1
56. On agricultural premises, heating appliances shall be fixed so as to maintain an appropriate distance from livestock. In the absence of manufacturer’s guidance, a radiant heater used in the vicinity of livestock should be placed at a distance of not less than:
a) 0.5m
b) 1.5m
c) 2.0m
d) 2.5m
57. In a caravan park, the maximum number of socket outlets which can be protected by an RCD is:
a) 2 b) 3 c) 6 d) 1
58. In exhibitions, protection against thermal effects must be provided for luminaries mounted below a height of:
a) 1m
b) 2.5m
c) 3m
d) 5m
59. For household installations, as a rule of thumb, the floor area served by a single 20A radial circuit using socket outlets to BS 1363 may be: a) up to 20m²
b) up to 50m² c) up to 100m² d) unlimited
60. Prior to an inspection in accordance with BS 7671, the competent person carrying out the work shall normally:
a) ensure that all switches are off
b) disconnect the installation from the supply c) disconnect all fixed appliances
PAPER 5
MOCK EXAM
2382-10 Test Questions-Paper 5
1. To which one of the following situations does BS 7671 apply? a) the manufacture of electrical equipment
b) the inspection and testing of the electrical installation on an oil rig
c) the design of an electrical installation for a caravan site d) the public electricity supply system
2. Which one of the following is listed under exclusions from the scope of BS 7671?
a) saunas
b) swimming pools c) marinas
d) lightning protection
3. Which one of the following sets of regulations is non-statutory? a) Electricity Safety, Quality and Continuity Regulations b) Electricity at Work Regulations
c) Building Regulations d) BS 7671
4. BS 7671 defines low voltage a.c. between conductors as voltage: a) below 250 V a.c
b) below 1000 V a.c. but above 50 V a.c. c) above 50 V a.c. but below 500 V a.c. d) above 250 V a.c. but below 1000 V a.c. 5. An ordinary person is a person who:
a) is skilled at electrical work b) works in electrical maintenance c) is neither skilled nor instructed d) at least 18 years old
6. A 12 V fire alarm circuit is classified by BS 7671 as: a) a Band I circuit
b) a Band II circuit c) a Band III circuit d) an unclassified circuit
7. Which one of the following is NOT a classification of external influence? a) current rating b) environmental conditions c) construction of buildings d) utilisation
8. The type of building construction is an external influence which, in an electrical installation, will affect the choice of:
a) equipment and wiring b) method of earthing c) overcurrent protection d) supply voltage
9. Non-sheathed cables for fixed wiring, other than protective conductors, should always be installed in:
a) dry conditions b) trenches
c) conduit or trunking d) sub-zero temperatures
10. Domestic ring final circuits are used to supply BS 1363 socket outlets. If the floor area to be served is limited to 50 m², the cable feeding the circuit must be:
a) 4 mm² b) 2.5 mm² c) 1.5 mm² d) 6 mm²
11. A domestic final ring circuit may:
a) supply any number of socket-outlets over an area of 200 m² b) feed an immersion heater
c) require additional protection by an RCD d) supply a cooker rated at 2.5 kW
12. Where thermoplastic insulated and sheathed cables are installed in a plastered wall at a depth of 20 mm and are not protected against mechanical damage, they must be:
a) run in “safe zones”
b) protected by a 30 mA RCD c) coloured red
13. A two-storey domestic dwelling should have a minimum of two lighting circuits in order to:
a) make the installation process easier
b) reduce the load on the consumer’s control unit c) avoid danger in the event of a fault
d) enable a greater variety of luminaries to be used 14. A system is defined as:
a) the kWh meter and an installation b) the distribution cables to an installation c) the consumer’s terminals of an installation d) a single source of energy and an installation 15. The term “basic protection” refers to:
a) protection against electric shock under fault free conditions b) extra-low voltage terminals
c) protection against electric shock under a single fault condition d) live parts within an appliance
16. Within a 230 V single-phase, metal clad fuse board, access to the line and neutral busbars are protected by insulation and by secured intermediate barriers. The fuse board may be:
a) opened without use of a key or tool b) left unearthed
c) used to accommodate SELV circuits
d) used to accommodate ELV circuit conductors 17. A socket-outlet used for a SELV system should:
a) not have a protective conductor contact b) be of a two-pin type
c) be marked SELV
d) have a protective conductor contact
18. Which one of the following is recognised as a means of providing fault protection?
a) protection by insulation of live parts b) protection by automatic disconnection c) protection by placing out of reach d) protection by obstacles
19. Where SELV is used in normally dry conditions, basic protection is unnecessary where the nominal voltage does not exceed:
a) 12 V a.c. b) 25 V a.c c) 50 V a.c d) 60 V a.c.
20. Obstacles may be used to provide basic protection providing: a) the circuit voltage does not exceed 250 V
b) the installation is under the control of a skilled person c) the installation is contained within steel conduit
d) an RCD is fitted
21. Overload current is defined as the overcurrent:
a) that causes protective devices to operate correctly b) occurring in a circuit which is electrically sound c) resulting from a fault of negligible impedance
d) flowing in a phase conductor when in contact with exposed conductive parts
22. An overload current could arise when:
a) excessive mechanical load is applied to an electric motor
b) a forward/reverse controller attempts to switch a motor both directions simultaneously
c) contamination of a motor terminal block results in tracking
d) an electrician drills into a busbar chamber and touches a live busbar with the drill
23. Where the overcurrent device is intended to afford protection against overload, l2 must not exceed lz multiplied by:
a) 0.735 b) 1.45 c) 1.8 d) 2.5
24. Omission of devices for protection against overload is not permitted for: a) secondary circuits of current transformers
b) circuits which supply fire extinguishing devices c) exciter circuits of rotating machines
25. Which one of the following may be used to provide emergency switching for an electric motor?
a) a key switch latched in the on position b) a plug and socket
c) a switch fuse with a removable handle d) a device which latches in the off position
26. A section of a factory requires urgent non-electrical repairs to a machine. The type of switching provided to allow this work to proceed would be switching for:
a) mechanical movement b) mechanical maintenance c) emergency
d) safe operation
27. Which one of the following shall not be used as an isolator? a) circuit breakers
b) plugs and socket outlets c) semiconductor devices d) fuse links
28. Where PME conditions apply, the main protective bonding conductor shall be:
a) half the csa of the earthing conductor and with reference to Table 54.7
b) selected in accordance with the supply neutral and Table 54.8 c) determined after consultation with the consumer
d) the same csa as the incoming line conductor
29. Which one of the following cannot be used as an earth electrode? a) copper water supply pipe
b) earth tape or wire
c) lead sheath covering of cable
d) welded reinforcement of concrete embedded in the earth
30. Using Table 54.7 of BS 7671, the minimum cross-sectional area of a circuit protective conductor with a 10 mm² line conductor will be:
a) 25 mm²
b) 16 mm²
c) 10 mm²
