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How the 2391-52 inspection and testing exam works: format, pass mark and the practical
The City & Guilds 2391-52 explained: the 60-question 2391-052 online test (120 minutes, approx. 75%), the three books you can take in, the 2391-502 practical tasks at your centre, and how Amendment 4 fits in.
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The City & Guilds 2391-52 is the Level 3 Award in Initial and Periodic Inspection and Testing of Electrical Installations. It covers both initial verification and periodic inspection, and it has two parts: an online multiple-choice test, 2391-052, and a practical assignment, 2391-502, made up of Tasks A, B and C. You need both.
This guide explains how each part works, what you can take in with you, how the test is split and where Amendment 4 to BS 7671 fits in. Everything here comes from City & Guilds' own documents, listed at the end.
- Qualification
- City & Guilds 2391-52, Level 3, Ofqual 603/1275/0
- Online test (2391-052)
- 60 multiple-choice questions in 120 minutes
- Pass mark
- Approx. 75% (about 45 out of 60)
- Books in the test
- BS 7671, the IET On-Site Guide and IET Guidance Note 3, paper copies only
- Practical (2391-502)
- Task A, B and C, run and marked at an approved centre
- Entry
- A relevant Level 3 electrotechnical qualification; 18 or over
Who the 2391-52 is for
City & Guilds expects candidates to hold a relevant Level 3 electrotechnical qualification already, and its handbook says the award isn't intended for people who are new to the industry or have limited experience in it. You register through an approved centre, and you must be 18 or over.
It covers both sides of the job: initial verification of new work, which ends in an Electrical Installation Certificate, and periodic inspection and testing of existing installations, which ends in an Electrical Installation Condition Report (EICR). There are two sister awards that cover one side each, 2391-50 and 2391-51; see the comparison further down.
The online test: 2391-052
The knowledge test is taken on City & Guilds' e-volve system at your centre, under exam conditions. It's open book, invigilated and graded pass or fail.
How many questions, and how long?
There are 60 questions and you have 120 minutes, which is 2 minutes a question. That sounds comfortable, but with three books to search it goes quickly. A common way to run out of time is looking up things you could answer from understanding.
What is the 2391-52 pass mark?
City & Guilds gives it as approximately 75%, about 45 out of 60. The handbook says the pass mark may be adjusted to keep standards consistent between groups of candidates, so treat it as a guide rather than a fixed line. That's a much higher bar than the 18th Edition's approx. 60%, so plan to score well above 75% in your practice mocks before you book.
Calculator and marking
A non-programmable scientific calculator is allowed in City & Guilds electrotechnical assessments. No negative marking is published, so answer every question, even if the last few are your best guess.
What's on the paper
The qualification has one unit, Unit 502, with five learning outcomes. City & Guilds publishes how many of the 60 test questions come from each one:
| Learning outcome | What it covers | Questions |
|---|---|---|
| 1 | Requirements for inspection and testing: purpose, legislation, documents and signatories | 13 |
| 2 | Safety management: risk assessment, the Electricity at Work Regulations and safe isolation | 3 |
| 3 | Inspection: the schedule of inspections, using your senses, unsatisfactory items and IP codes | 11 |
| 4 | Testing: instruments, the test sequence, every test and what the results mean | 33 |
| 5 | Performing inspection and testing (assessed only by the practical) | 0 |
| Total | 60 |
Testing is more than half the paper. Learning outcome 4 covers continuity of protective conductors and ring final circuits, insulation resistance, polarity, earth electrodes, earth fault loop impedance, RCDs, prospective fault current, phase sequence, functional testing and voltage drop, plus the factors that affect each reading and how you classify a result: C1, C2, C3 or FI.
Exam tip
Don't let learning outcome 1 surprise you. Thirteen questions on the purpose of inspection, the documents and who signs what is more than a fifth of the paper, and most of it is understanding rather than lookup.
What books can you take into the 2391-052 test?
Unlike the 18th Edition exam, which allows BS 7671 only, the 2391-052 test allows three books, all as paper copies:
- BS 7671, the IET Wiring Regulations;
- the IET On-Site Guide;
- IET Guidance Note 3: Inspection & Testing.
Electronic copies can't be used in e-volve tests. City & Guilds asks candidates to use the current version of BS 7671 and the most up-to-date versions of the other books. Our reading is that from 15 October 2026 that means BS 7671:2018+A4:2026, the On-Site Guide 9th Edition and Guidance Note 3 10th Edition, but check with your centre before you buy.
What you can and can't do to your books
City & Guilds' permitted materials guide allows:
- stick-on paper page markers (tabs);
- highlighting;
- very short handwritten cross-references to regulation or BS numbers elsewhere in the book;
- official corrigenda and amendment pages, and corrections to known published errors.
It doesn't allow added note pages, formulae (printed or handwritten), extra printed pages, handwritten procedures, or handwritten descriptions of text that doesn't appear elsewhere in the book.
The practical: 2391-502, Tasks A, B and C
The practical assignment happens at your centre, on the centre's own installation rig, and is marked by the centre's assessors to City & Guilds' materials. An online course can teach the knowledge behind it, but it can't deliver or assess it.
| Task | What it is | Time | Books |
|---|---|---|---|
| A | Visual inspection of an electrical installation | 30 minutes | None |
| B | Practical inspection and testing, with the documentation | 2 hours 30 minutes | BS 7671, OSG and GN3, for confirming test results only |
| C | Short-answer written paper | 80 minutes | BS 7671, OSG and GN3 |
City & Guilds doesn't publish the pass marks for the three tasks, the number of defects in Task A or the number of questions in Task C; the assessor guidance and assignment packs are only available to centres. Be wary of anyone quoting exact figures as official.
What you can prepare: recognising common defects from memory (Task A allows no books at all), a safe and methodical test routine, completing the model forms accurately, and writing clear short answers.
Amendment 4 and the 2391-52
BS 7671:2018+A4:2026 was published on 15 April 2026, and the previous version is withdrawn on 15 October 2026. City & Guilds says the 2391 assessments that test BS 7671 knowledge will be aligned to Amendment 4 "in due course", but it hasn't published a date.
So learn the A4 position, and know where it differs from the old forms. The biggest change for inspectors is on the EICR: under the A4 model form, FI no longer makes a report unsatisfactory; only C1 and C2 do. Our guide to EICR coding for the 2391-52 covers it in detail. Ask your centre which edition your test assumes.
2391-50, 2391-51 or 2391-52?
City & Guilds offers three pathways with the same underlying knowledge but different tests:
| Pathway | Covers | Online test |
|---|---|---|
| 2391-50 | Initial verification | 40 questions, 90 minutes, approx. 75% |
| 2391-51 | Periodic inspection and testing | 40 questions, 90 minutes, approx. 75% |
| 2391-52 | Initial verification and periodic inspection | 60 questions, 120 minutes, approx. 75% |
The City & Guilds 2391 page lists 31 August 2028 as the last registration date for all three, and no successor has been announced.
How to prepare
The skills the test rewards are understanding why each test is done, knowing what a sensible reading looks like, and finding the right table fast in three books. These are the mistakes that come up most:
- doing only the first step of the ring final circuit test, or cross-connecting the wrong pairs;
- not sense-checking results, for example comparing R1+R2 with Zs − Ze;
- comparing a measured Zs with an uncorrected Chapter 41 value;
- applying the old rule that FI makes an EICR unsatisfactory;
- using the wrong insulation resistance test voltage or minimum (1 MΩ for circuits up to 500 V, not 0.5 MΩ);
- using a non-contact detector to prove dead, which GS38 says it can't do;
- not knowing your way around Guidance Note 3, even though it's a permitted book.
Practise at the real pace, two minutes a question, with your own tabbed books on the desk. The Inspection & Testing course has lessons for every learning outcome, explained questions and timed 60-question mocks spread like the real test.
Frequently asked questions
How many questions are in the 2391-52 exam?
The 2391-052 online test has 60 multiple-choice questions, and you have 120 minutes. The qualification also needs the 2391-502 practical assignment, which is assessed at your centre.
What is the pass mark for the 2391-52?
City & Guilds gives the 2391-052 test pass mark as approximately 75%, about 45 out of 60, and says it may be adjusted. It doesn't publish the pass marks for the practical tasks.
Can I take the On-Site Guide into the 2391 exam?
Yes. The 2391-052 test allows paper copies of BS 7671, the IET On-Site Guide and IET Guidance Note 3. Task A of the practical allows no books.
Can I do the whole 2391-52 online?
No. You can revise online, but the 2391-052 test is sat at an approved centre, and the 2391-502 practical is carried out and marked there on the centre's rig.
Is there a 2391-26?
No. City & Guilds lists 2391-50, 2391-51 and 2391-52, and hasn't announced a replacement.
Do I need a 2391 to do EICRs under a certification scheme?
NICEIC says that from 1 October 2026, qualified supervisors and employed persons responsible for periodic inspection and testing need a recognised Level 3 inspection and testing qualification, such as 2391-51 or 2391-52, plus experience and ongoing CPD. That's a certification scheme rule, not law, so check with your own scheme.
Sources
- City & Guilds, 2391-52 qualification handbook, version 2.4 (April 2026): the test format, pass mark, test specification and entry expectations.
- City & Guilds, 2391 qualification page (updated 22 May 2026): the pathways, last dates and the Amendment 4 note.
- City & Guilds, Electrotechnical Guide to Assessments and Permitted Materials, version 3.1 (May 2026): task times, permitted books and what you may write in them.
- The Ofqual register entry for qualification 603/1275/0.
- NICEIC, guidance on the EAS changes (2026), for the scheme requirement.