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Free 18th Edition Practice Questions (BS 7671 Amendment 4)

Original questions written to BS 7671:2018+A4:2026, grouped by topic. Pick an answer to see the full workout. For the real exam experience, take a timed 18th Edition mock test.

Scope, object and fundamental principles

Q1. Which of these installations is excluded from the scope of BS 7671?

Show answer

Answer: B. Railway traction equipment and rolling stock

  • Regulation 110.2 lists installations BS 7671 does not apply to.
  • Railway traction equipment, rolling stock and signalling equipment are on that list, along with things like aircraft, offshore installations and lift aspects covered by their own standards.

Why the others are wrong:

A: EV charging is listed in 110.1.1 as within scope.

C: solar PV is listed in 110.1.1 as within scope.

D: caravans are listed in 110.1.1 as within scope.

Memory trick:

Trains, planes and ships run on their own rules.

Reg 110.2

Q2. Electrical equipment must be arranged to give sufficient space for what?

Show answer

Answer: B. Initial installation and later replacement of items

  • 132.12(a): sufficient space for the initial installation and later replacement of individual items
  • 132.12(b): accessibility for operation, inspection, testing, fault detection, maintenance and repair

If you can't get it out, you can't replace it.

Why the others are wrong:

A: 132.12 refers to installation and replacement of items.

C: 132.12 does not require storage space.

D: 132.12 is about space and access, not room ventilation.

Memory trick:

Room to fit it, room to swap it.

Reg 132.12

Q3. What does Part 1 say about periodic inspection and testing of installations?

Show answer

Answer: B. It is recommended for every installation, per Chapter 65

  • 135.1: it is recommended that every electrical installation is subjected to periodic inspection and testing
  • In accordance with Chapter 65
  • The designer recommends the interval to the first inspection (134.2.2)

Note the wording: a recommendation, not a requirement.

Why the others are wrong:

A: 135.1 recommends it for every installation.

C: 135.1 is a recommendation and sets no interval.

D: 135.1 recommends periodic testing regardless of alterations.

Memory trick:

Periodic: recommended for all, details in 65.

Reg 135.1

Definitions

Q4. What does an earthing conductor connect?

Show answer

Answer: D. The main earthing terminal to an earth electrode or other means of earthing

  • Earthing conductor: MET to the means of earthing (electrode or supplier's terminal).
  • CPC: equipment exposed-conductive-parts to the MET.
  • Bonding conductor: extraneous-conductive-parts to the MET.

Why the others are wrong:

A: that's a circuit protective conductor.

B: that's a protective bonding conductor.

C: that describes a PEN conductor.

Memory trick:

Earthing conductor goes to Earth; CPC goes to Circuits; bonding goes to pipes.

Reg Part 2

Q5. What is the function of isolation, as defined in Part 2?

Show answer

Answer: D. Making all or part of an installation dead by separating it from every source

  • Isolation is a function intended to make dead, for reasons of safety, all or a discrete section of the installation.
  • It does this by separating it from every source of electrical energy.

Isolation is what you use before electrical work, so separation from every source matters, including generators or PV.

Why the others are wrong:

A: that is emergency switching.

B: that is functional switching.

C: that relates to switching for mechanical maintenance.

Memory trick:

Isolate = Island it from every source.

Reg Part 2 (Isolation)

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Q6. How does Part 2 define a spur?

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Answer: C. A branch from a ring or radial final circuit

  • A spur is a branch from a ring or radial final circuit.
  • A ring final circuit is a final circuit arranged as a ring and connected to a single point of supply.

Many people think spurs only come off rings, but Part 2 includes radials too.

Why the others are wrong:

A: the definition covers branches from radial final circuits as well.

B: that is a distribution circuit, sometimes called a sub-main.

D: a spur is a branch of the circuit and need not be fused or feed a socket-outlet.

Memory trick:

Spur = Side branch off a ring OR radial.

Reg Part 2 (Spur)

Q7. Part 2 defines verification as comprising which activities?

Show answer

Answer: B. Inspection, testing and certification

  • Verification is all the measures that check compliance with BS 7671, comprising inspection, testing and certification.
  • Inspection is examination using all the senses as appropriate.
  • Testing uses measuring instruments to find values not detectable by inspection.

Verification is not complete until the certificate is issued.

Why the others are wrong:

A: certification is also part of the verification definition.

C: inspection is part of verification, and reporting relates to periodic inspection and testing.

D: design is not one of the listed verification activities.

Memory trick:

Verification = I, T, C: Inspect, Test, Certify.

Reg Part 2 (Verification)

Protection for safety

Q8. In a location with particular fire risks, what does BS 7671 require of a temperature cut-out device?

Show answer

Answer: C. It shall have manual reset only

  • Regulation 422.1.3: a temperature cut-out device shall have manual reset only

Someone must check why it tripped before it is restored.

Why the others are wrong:

A: auto reset could restart a hazard; manual reset is required.

B: no trip temperature is set by 422.1.3.

D: only manual reset is permitted.

Memory trick:

Cut-out in a fire risk area: a person resets it.

Reg 422.1.3

Q9. Which statement about emergency switching off is correct?

Show answer

Answer: B. One single action must interrupt the appropriate supply

  • Regulation 465.3: emergency switching must act as directly as possible on the supply conductors
  • One single action must interrupt the supply
  • 465.2: where shock risk exists, disconnect all live conductors

In an emergency there's no time for multiple steps.

Why the others are wrong:

A: a single action is required.

C: it must act as directly as possible.

D: where shock risk exists, all live conductors must be disconnected.

Memory trick:

Emergency: one push, all off.

Reg 465.3

Selection and erection of equipment

Q10. Where may an automatic reclosing device for ADS protection be installed?

Show answer

Answer: B. Where access is restricted to skilled or instructed persons

  • Automatic reclosing ADS devices may only be installed where access is restricted to instructed or skilled persons.
  • A warning notice must be displayed near the point of access.

Auto-reclosing could re-energize a fault while someone works on it.

Why the others are wrong:

A: access is not restricted in domestic premises.

C: RCD presence does not override the access restriction.

D: circuit type is not the condition; restricted access is.

Memory trick:

Auto-reclose only behind locked doors.

Reg 531.1.1

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Q11. What warning notice must be at each point of access to a battery room or battery enclosure?

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Answer: A. That live parts can remain energized after isolation

  • Permanent notice e.g. 'BATTERY - Live parts can remain energized after isolation'.
  • Black text and symbols on a yellow background.
  • PCE notice: 'Isolate both AC and DC sides before servicing'.

Why the others are wrong:

B: not the notice this regulation requires.

C: not the required notice.

D: not the required wording.

Memory trick:

Batteries never truly die: warn it.

Reg 570.6.8.202

Inspection and testing

Q12. When measuring the resistance of an insulating floor, where must one of the measurements be taken?

Show answer

Answer: B. About 1 m from any accessible extraneous-conductive-part

  • At least three measurements in the same location
  • One measurement approximately 1 m from any accessible extraneous-conductive-part
  • The other two at greater distances

The 1 m reading checks the area where someone could touch a conductive part.

Why the others are wrong:

A: the point is about 1 m away from it, not on it.

C: the stated distance is approximately 1 m, with the others further away.

D: location relative to extraneous-conductive-parts is what matters.

Memory trick:

One at one metre, two further away.

Reg 643.5.1

Q13. An instantaneous (general non-delay) RCD is tested at its rated residual operating current. What is the maximum operating time to confirm effectiveness?

Show answer

Answer: A. 300 ms

  • General non-delay RCD at IΔn: 300 ms maximum
  • This applies regardless of RCD Type, using an AC test

If it trips within this time, effectiveness is deemed verified.

Why the others are wrong:

B: 40 ms is not the time stated for a test at IΔn.

C: 500 ms is the upper limit for S type RCDs.

D: 130 ms is the minimum time for an S type RCD.

Memory trick:

Normal RCD: three hundred.

Reg 643.7.1

Q14. Which of the following is NOT a factor in deciding the frequency of periodic inspection and testing?

Show answer

Answer: C. The cost of carrying out the inspection

  • Factors: type of installation and equipment, use and operation, frequency and quality of maintenance, external influences
  • Previous certificates and reports are also considered

Cost is not a technical factor.

Why the others are wrong:

A: this is a listed factor.

B: this is a listed factor.

D: this is a listed factor.

Memory trick:

Type, Use, Maintenance, Influences: TUMI.

Reg 652.1

Special installations or locations

Q15. In arable or cultivated ground on agricultural premises, what is the minimum burial depth for cables?

Show answer

Answer: A. 1 m

  • Where vehicles and mobile machines operate: buried at least 0.6 m with added mechanical protection.
  • In arable or cultivated ground: at least 1 m.
  • Self-supporting suspension cables: at least 6 m high.

Ploughs dig deep, so cables in fields go deeper.

Why the others are wrong:

B: 0.6 m with added mechanical protection applies where vehicles operate, not arable ground.

C: 0.5 m is the marina underground cable depth.

D: 6 m is the height for self-supporting suspension cables.

Memory trick:

Plough land: bury a metre.

Reg 705.522

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Q16. When must the temporary installation of an exhibition stand be inspected and tested?

Show answer

Answer: A. On site after each assembly

  • Temporary installations of exhibitions, shows and stands shall be inspected and tested on site.
  • This is done to Chapter 64 after each assembly on site.

Every new build at a new venue counts as a new installation.

Why the others are wrong:

B: each assembly on site needs inspection and testing.

C: temporary stands are tested each time they are assembled.

D: there is no rating threshold for this requirement.

Memory trick:

Every build, every test.

Reg 711.6

Q17. Bare conductors are to be used in an ELV lighting installation. What is the maximum nominal voltage permitted?

Show answer

Answer: A. 25 V AC or 60 V DC

  • Bare conductors in ELV lighting: nominal voltage not exceeding 25 V AC or 60 V DC.
  • They must also have the cross-section required by 715.524 and not be placed directly on combustible material.

The lower limit applies because the conductors are uninsulated.

Why the others are wrong:

B: this is the general ELV limit, not the limit for bare conductors.

C: these values are lower than the stated limits.

D: 25 V AC is right, but the DC limit is 60 V, not 120 V.

Memory trick:

Bare means less: 25 AC, 60 DC.

Reg 715.521.106

Q18. Connecting hardware for data cables used to distribute DC power must support what continuous operating current per contact?

Show answer

Answer: C. 750 mA

  • Connecting hardware must comply with ISO/IEC 11801-1 and support 750 mA per contact continuously.
  • If equipment may be unplugged under load, the hardware must meet the BS EN 60512-9-3 endurance test.

750 mA per contact is the figure to remember.

Why the others are wrong:

A: this is below the stated value.

B: this is not the figure given in the regulation.

D: this is well below the stated value.

Memory trick:

Three-quarters of an amp per pin.

Reg 716.526

Part 8 and Appendices

Q19. For Reference Method C (clipped direct), how far from the wall may the cable be?

Show answer

Answer: B. Less than 0.3 times the cable diameter

  • Method C: cable on a wooden or masonry wall with a gap less than 0.3 x cable diameter.
  • Fixed to or embedded in masonry the capacity may be higher.

Close to the surface means Method C.

Why the others are wrong:

A: spacing of 0.3 times or more is moving towards free air methods.

C: the limit is 0.3 times, not 3 times.

D: that is the free air clearance for single-core cables.

Memory trick:

C for Clipped, within 0.3 D.

Reg Appendix 4 7.1

Q20. When should the extent and limitations of an EICR be agreed with the person ordering the report?

Show answer

Answer: A. Before the inspection and testing starts

  • Extent of installation covered is recorded in Section D
  • It should be agreed prior to the inspection and testing
  • Agreement may also involve other parties, such as a licensing authority, insurer or mortgage provider

Operational limitations found on the day, like no access, are also noted in Section D.

Why the others are wrong:

B: the guidance says extent and limitations are agreed prior to the work.

C: limitations are agreed for every report, not only when danger is found.

D: they apply to the current report, so must be agreed beforehand.

Memory trick:

Agree the boundaries before you start walking.

Reg Appendix 6

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Q21. Three multicore cables are installed in separate ducts buried in the ground with the ducts touching. What grouping factor applies?

Show answer

Answer: A. 0.75

  • Table 4C3 (Method D1, single-way ducts), 3 ducts: touching 0.75, 0.25 m 0.85, 0.5 m 0.90, 1.0 m 0.95.

Spacing ducts apart improves the factor.

Why the others are wrong:

B: that is for three ducts with 0.25 m clearance.

C: that is for three cables buried direct and touching (Table 4C2).

D: that is for three ducts with 0.5 m clearance.

Memory trick:

Touching ducts cost a quarter.

Reg Table 4C3

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