How to Pass the 2391 First Time

Feb 1
The City & Guilds 2391 Inspection and Testing qualification is one of the most respected — and most feared — exams in the electrical industry. Whether you’re an apprentice, improver, or experienced electrician returning to testing, passing the 2391 first time is absolutely achievable with the right approach.

What the 2391 courses involve.

The qualification is split into three pathways:

1. 2391-50 - Level 3 Award in Initial Verification of Electrical Installations

2. 2391-51 - Level 3 Award in Periodic Inspection and Testing of Electrical Installations

3. 2391-52 - Level 3 Award in Initial and Periodic Inspection and Testing of Electrical Installations
Make sure you choose the correct course as 1 & 2 have limitations. 2391-52 is the best approach for competent electricians, read more below.

What the 2391-50 course Involves

  • Task A - A Practical assessment of Initial verification and certification. (2.5hrs)
  • Task B - Written exam paper (100%)
  • Task C - Online GOLA exam 40 questions (75%)
    Completing this course only allows you to test and verifify New installations

What the 2391-51 course Involves

  • Task A Visual Inspection of photographs (100%)
  • Task B - A Practical assessment of Periodic Inspection, Testing and certification. (2.5hrs) additional time added for certificates
  • Task C - Written exam paper (100%)
  • Task D - Online GOLA exam 40 questions (75%)
    Completing this course only allows you to complete periodic inspections.

What the 2391-52 course Involves

  • Task A Visual Inspection of photographs (100%)
  • Task B - A Practical assessment of Periodic & Initial verification inspection, testing and certification. (2.5hrs) additional time added for certificates
  • Task C - Written exam paper (100%)
  • Task D - Online GOLA exam 60 questions (75%)
    Completing this course only allows you to complete periodic inspections and verify new installations. (examtrain advise this route)

Common Mistakes Learners Make

1. Not knowing the testing sequence
The examiners expect you to follow the correct sequence of testing. Mixing up IR, continuity, polarity, or Zs testing is a guaranteed fail.
2. Confusing Zs and Ze
This is one of the most common errors.
Ze = external earth fault loop impedance
Zs = total earth fault loop impedance (Ze + R1+R2)
3. Poor IR testing technique Learners often:
Test with loads connected (lamps in place)
Forget to disconnect sensitive equipment
Don’t link L–N for combined testing
4. Not referencing BS 7671
You’re not expected to memorise every value — but you are expected to know where to find them in the BS7671 book and write them down
5. Not reading the questions correctly on the written paper
Read the question, answer the question, then read the question again and make sure your answer is sufficient. (does it answer who and why etc.)

The Correct Testing Sequence (Step by Step)

Dead Tests
1. Continuity of protective conductors (CPC)
2. Continuity of ring final circuits
3. Insulation resistance (IR)
4. Polarity (dead)
Live Tests
5. Supply Polarity
6. Earth fault loop impedance (Zs)
7. Prospective fault current (PFC)
8. RCD testing
9. Functional testing
If you can recite this sequence confidently, you’re already ahead of most candidates.

Sample of 2391 Questions

You measure insulation resistance of 0.18 MΩ on a lighting circuit. What should you do?

Ans: Investigate and rectify before continuing.

What does Zs represent?

Ans: Total earth fault loop impedance.

Which test must be completed before energising a circuit?

Ans: Continuity of protective conductors.

Revision strategy that works.

1. Daily Short, focused sessions

20–30 minutes of active recall beats hours of passive reading.

2. Use mock exams

The 2391 GOLA exam follows a predictable pattern. Practising realistic questions is the fastest way to improve, READ the question, answer the question, if you don't know the answer, bookmark and guess. check all bookmarks (flags) before you submit a final time.

3. Learn the “why”, not just the “what”

If you understand why a test is performed, you’ll never forget the method.

4. Practise the testing sequence until automatic

You should be able to perform it under pressure, using different makes and models of multi function test equipment.

Conclusion

Passing the 2391 first time is absolutely possible. With structured revision, realistic mock exams, and a clear understanding of the testing process, you can walk into the assessment with confidence. If you have never taken the 2391 then we advise you start as a beginner, then jump to Expert as this gives you a comprehensive challenge and prepares you for what is to come. If you have attended the course and need help to pass the GOLA then take the Intermediate route.


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