2391 Exam Technique

<h2>Exam structure</h2>
<p>The C&G 2391 Unit 301 written exam is typically 2.5 hours, worth approximately 100 marks. It contains a mix of question types:</p>
<ul>
<li><strong>Short answer</strong> (1–3 marks) — state a value, name a regulation, give a definition</li>
<li><strong>Extended answer</strong> (4–8 marks) — describe a procedure, explain a concept, perform a calculation</li>
<li><strong>Calculation questions</strong> — Zs, PFC, voltage drop, derating</li>
</ul>

<h2>High-value question types to prepare for</h2>
<ol>
<li>"Describe the procedure for carrying out an insulation resistance test on a ring final circuit" (6 marks)</li>
<li>"Explain why Zs must not exceed the maximum permitted value" (4 marks)</li>
<li>"State the purpose of the three-step ring final continuity test and describe Step 1" (5 marks)</li>
<li>"Calculate the Zs for a circuit given Ze and R1+R2, and compare against the maximum for a 32A Type B MCB" (4 marks)</li>
<li>"State THREE items that must appear on the schedule of circuit details" (3 marks)</li>
</ol>

<h2>Calculation strategy</h2>
<ul>
<li><strong>Write the formula first</strong> — examiners award marks for correct formula even if you make an arithmetic error</li>
<li><strong>Substitute values clearly</strong> — show each step</li>
<li><strong>State the units</strong> — Ω, V, A, MΩ, mV/A/m</li>
<li><strong>Check against the limit</strong> — always state whether the result passes or fails</li>
<li><strong>Reference the table</strong> — "From BS 7671 Table 41.3..."</li>
</ul>

<h2>Extended answer strategy</h2>
<ul>
<li>Use a numbered list for procedures — examiners mark against a list of valid points</li>
<li>Reference regulations where you know them — adds credibility and marks</li>
<li>Use correct technical terminology throughout</li>
<li>If asked to "describe" something, include: what, how, and why</li>
<li>Do not leave blanks — a partial answer always scores more than nothing</li>
</ul>

<h2>Time management</h2>
<ul>
<li>Roughly 1.5 minutes per mark — use this as your guide</li>
<li>Attempt all questions — no negative marking</li>
<li>Do calculations first (fixed marks) then extended answers</li>
<li>Leave 10 minutes to check calculations at the end</li>
</ul>