Free mock exam
Safe Isolation — Level 3 Fault Diagnosis Practice
Free topic-focused mock exam: 30 random questions from a pool of 49 on Safe Isolation, drawn from the wider Level 3 Fault Diagnosis bank. 35-minute timer, 70% to pass, worked explanation on every question. Use this when you've taken the full mock once and want to drill the topics you got wrong.
- Questions
- 30
- Time limit
- 35 min
- Pass mark
- 70% · 21/30
- Question bank
- 49
Free, no sign-up. Retake as many times as you like — different questions each time.
Sample questions
01What is the maximum length of exposed metal permitted at the tip of a test probe under HSE guidance on test equipment?
- A20 mm of exposed metal at the tip
- BNo limit, provided finger barriers are fitted
- C10 mm of exposed metal at the tip
- D4 mm of exposed metal at the tip
Why: GS38 recommends no more than 4 mm of exposed metal at the probe tip (many manufacturers limit this to 2 mm), together with finger barriers, to protect against accidental contact and arc flash.
02Which statement about proving a circuit dead during safe isolation is correct?
- ATest at the distribution board only, as the point of work is fed from it
- BProve the approved voltage indicator on a known source, test between all conductors at the point of work, then prove the indicator again
- CA non-contact voltage pen is enough on its own, provided it stays silent
- DTest once with a multimeter set to resistance, as the supply is already switched off
Why: Prove, test, prove: an approved voltage indicator to GS38 is confirmed on a known source or proving unit, used between all conductors at the point of work, then confirmed again so a tester that failed during the test cannot give a false dead reading. On-Site Guide Figure M.2 secures (locks off) after verifying dead; HSE HSG85 and Electrical Safety First BPG2 lock off and post the notice before proving dead. Both are recognised, so follow your employer's or assessment centre's procedure.
03Why must a voltage indicator be proved both before and after the test for dead?
- ATo comply with the manufacturer's warranty terms for the tester
- BTo increase the sensitivity of the tester for low voltage readings
- CTo recharge the tester battery between each set of test readings
- DTo ensure the tester is working correctly and hasn't failed during testing
Why: Proving before confirms the tester works, proving after confirms it still works - if the tester failed during testing, a false 'dead' reading could result.
Common questions
Is the Safe Isolation mock exam free?
Yes, it is free with no sign-up needed. Questions are pulled at random from a substantial bank, with a worked explanation on every question after you submit.
Can I retake the mock exam?
Yes. Every attempt picks a different random selection and reshuffles the options, so each retake gives you genuinely new questions. No limit on retakes.
Does this count as a qualification?
No. This is independent practice material and does not award a qualification, card or certificate. Where a subject has a formal qualification or card, you gain it through an approved provider.