18th Edition (BS 7671) Exam Prep: Free Mock Test & Practice Questions

18th Edition (BS 7671) Exam Prep

C&G 2382-style open-book practice — regs navigation under time pressure.

Pass mark 18/30 60 minutes C&G 2382 style How many can I get wrong?

Little and often beats one big session. Five minutes on the bus counts.

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Try 3 real 18th Edition (BS 7671) Exam Prep questions

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Q1. BS 7671 applies to the design, erection and verification of electrical installations operating at voltages up to and including which limit for a.c.?

A. 1000 V
B. 1500 V
C. 650 V
D. 500 V

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✓ Answer: A. 1000 V

BS 7671 covers installations operating at voltages up to and including 1000 V a.c. (and 1500 V d.c.). Above these limits the installation falls outside the scope of the Regulations and other standards apply.

Q2. Automatic disconnection of supply (ADS), the principal method of fault protection in BS 7671, relies on which combination of measures?

A. Basic insulation, protective earthing, and either an overcurrent device or RCD, together with protective equipotential bonding
B. Double insulation, SELV and physical barriers
C. Obstacles, placing out of reach and non-conducting locations
D. Electrical separation, PELV and FELV

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✓ Answer: A. Basic insulation, protective earthing, and either an overcurrent device or RCD, together with protective equipotential bonding

ADS combines basic protection (insulation of live parts) with fault protection achieved by connecting exposed-conductive-parts to the protective earthing system, protective equipotential bonding, and a protective device that disconnects the supply automatically should a fault occur. The other options describe alternative or supplementary protective measures, not the core ADS requirement.

Q3. Where a single-phase and a three-phase supply share a common consumer unit enclosure, what does BS 7671 require regarding the isolation of each supply?

A. Each supply must have its own separate means of isolation, and a warning notice must indicate the presence of more than one supply
B. A single isolator can serve both supplies provided it is rated for the combined current
C. No warning notice is needed if both supplies are clearly labelled with coloured tape
D. Only the three-phase supply requires isolation

Show answer & explanation

✓ Answer: A. Each supply must have its own separate means of isolation, and a warning notice must indicate the presence of more than one supply

Regulation 537.1.4 (and related notice requirements) requires separate isolation for each source and a durable warning notice at the point of isolation where more than one supply exists, so that a person isolating one supply is not exposed to a second live source. Coloured tape alone does not satisfy the notice requirement.

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18th Edition (BS 7671) Exam Prep — common questions

Frequently asked

How many questions are in the 18th Edition (BS 7671) Exam Prep?

The exam has 30 questions. Every Revision Robin mock uses the same 30-question format so your practice matches the real thing.

What is the pass mark for the 18th Edition (BS 7671) Exam Prep?

You need 18 out of 30 correct to pass, which is about 60%. Our mocks mark you against this exact threshold.

How long do you get?

The test is timed at 60 minutes. Our full mock runs on the same clock so you can practise your pacing.

Are these the real exam questions?

No. Our questions are original and written to match the current syllabus, so they give realistic practice without copying the official paper. Every answer comes with a plain-English explanation. Always confirm current rules and content with C&G 2382 style.