Free mock exam
Insulation Resistance — C&G 2391 Inspection & Testing Practice
Free topic-focused mock exam: 30 random questions from a pool of 34 on Insulation Resistance, drawn from the wider C&G 2391 Inspection & Testing 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
- 34
Free, no sign-up. Retake as many times as you like — different questions each time.
Sample questions
01What is the standard test voltage for insulation resistance testing on a 230V circuit?
- A250V DC
- B500V DC
- C230V AC
- D1000V DC
Why: 500V DC is the standard test voltage for insulation resistance testing on circuits up to and including 500V.
02What is the minimum acceptable insulation resistance for a 230V installation?
- A0.1 MΩ
- B2.0 MΩ
- C1.0 MΩ
- D0.5 MΩ
Why: The minimum acceptable insulation resistance for a 230V installation is 1.0 MΩ (1 megohm).
03What should be done with electronic equipment before insulation resistance testing?
- ATest it at a reduced voltage of 250V DC
- BSwitch it off but leave it wired into the circuit
- CDisconnect or bypass it to prevent damage
- DLeave it connected to test the equipment as well
Why: Electronic equipment must be disconnected or bypassed as the 500V test voltage can damage sensitive components.
Common questions
Is the Insulation Resistance 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.