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

  1. 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.

  2. 02The correct sequence for safe isolation is:
    • ASecure, identify, work, then isolate the supply
    • BIdentify, isolate, secure, prove dead, prove tester
    • CIsolate, work, then test for dead afterwards
    • DProve dead, isolate, then secure the supply

    Why: Safe isolation follows: identify circuit, isolate from supply, secure isolation (lock off), prove tester, test for dead, prove tester again.

  3. 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 — 100% free, 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 towards the real qualification?

No — this is independent practice material. To gain the actual qualification you need to sit the official assessment through an approved provider.

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