Free mock exam
Earthing & Bonding — 18th Edition (BS 7671) Practice
Free topic-focused mock exam: all 21 questions on Earthing & Bonding, drawn from the wider 18th Edition (BS 7671) bank. 60-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
- 21
- Time limit
- 60 min
- Pass mark
- 70% · 15/21
- Question bank
- 21
Free, no sign-up. Retake as many times as you like — the questions are reshuffled, with the answer order changed.
Sample questions
01Before commencing work, what must be established about the installation?
- ASupply characteristics and earthing system
- BThe original installer of the consumer unit
- CThe exact age of every cable installed
- DThe energy supplier and tariff in use
Why: Knowing the supply characteristics (Uo, frequency) and earthing arrangement (TN-S, TN-C-S, TT) is fundamental to designing protection and working safely.
02You discover a protective conductor is not continuous. What action should you take?
- AIncrease the rating of the protective device to compensate
- BRecord the defect and inform the responsible person
- CReplace the conductor with a larger line conductor
- DContinue testing and note it on the next inspection report
Why: A discontinuous protective conductor is potentially dangerous; it must be recorded as a defect and the responsible person informed so it can be remedied.
03For a domestic supply with 25 mm² tails, the main earthing conductor sized from Table 54.7 is typically:
- A16mm²
- B6mm²
- C4mm²
- D10mm²
Why: Table 54.7 relates the protective conductor to the line conductor: for line conductors over 16 mm² and up to 35 mm², 16 mm² copper. So 25 mm² tails need a 16 mm² main earthing conductor (the distributor may ask for more). 10 mm² is the usual main protective bonding size for a PME supply with tails up to 35 mm² (Table 54.8).
Common questions
Is the Earthing & Bonding 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.