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 — 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.
