Registered Electrical Engineer (G&T) common mistakes
Registered Electrical Engineer (G&T) · Understand the traps and how to avoid them.
When a problem asks for the protective device rating or conductor ampacity, the candidate computes the load current and stops there, skipping the 125% continuous-load factor, the 80% derating, or the ambient-temperature and conductor-bundling correction factors entirely.
Load-calculation formulas are learned in isolation from the correction-factor tables, so the candidate treats the final ampacity number as the answer rather than the starting point. Time pressure makes the candidate drop the table lookups because they feel like extra steps rather than part of the calculation.
What to do instead
Before solving, write the three correction stages explicitly on the scratch paper: demand/continuous factor, ambient temperature factor, bundling/conduit-fill factor. Then apply them in order and show the intermediate values. Practise a set of problems where you must state each factor and its source table before computing, so the sequence becomes automatic.
The candidate treats a transformer, generator, or motor as an ideal element and ignores impedance, excitation current, or starting current, then selects a cable or breaker that is undersized for fault or inrush conditions.
Textbook per-unit problems often present ideal machines, so the habit carries over into design questions where real equipment data (percent impedance, locked-rotor current, subtransient reactance) is the whole point. The candidate also confuses steady-state rating with short-time withstand capability.
What to do instead
For every equipment item, ask: what is the nameplate impedance and what is the worst-case current it can deliver or draw? Build a short checklist (transformer %Z, motor LRC, generator X''d) and use it whenever sizing a device. Work through at least one fault-current and one motor-starting problem per study session until the habit is reflexive.
When computing symmetrical fault current or voltage drop, the candidate mixes per-unit, ohmic, and percentage-impedance values in a single calculation without converting to a common base, or applies the wrong base for the transformer ratio.
Each method is learned in a separate chapter and the candidate never practises switching between them mid-problem. The base-change formula (Z_new = Z_old × (S_new/S_old) × (V_old/V_new)²) is easy to misremember, especially the voltage term squared.
What to do instead
Adopt a fixed workflow: choose S_base and V_base, convert every impedance to per unit on that base, solve, then convert back. Write the base-change formula on the reference sheet and verify one known value (e.g., transformer %Z) after conversion. Do mixed-method drill problems where the input is deliberately given in different units.
The candidate answers protection-coordination questions by picking the device with the highest interrupting rating or the fastest trip curve, rather than checking selectivity between upstream and downstream devices and verifying the time-current curves overlap correctly.
The candidate conflates 'safe' with 'conservative' and assumes a bigger breaker is always acceptable. Time-current curve reading is a graphical skill that is rarely practised, so the candidate avoids it and substitutes a rule of thumb.
What to do instead
Practise reading time-current curves: identify the pickup, the instantaneous trip, and the coordination interval between two devices. For each coordination problem, sketch both curves and mark the minimum time margin. Learn the rule that the downstream device must clear the fault before the upstream device's curve is reached.
On generation and transmission questions, the candidate applies distribution-level assumptions (short lines, negligible charging current, unity power factor) to transmission problems involving line capacitance, Ferranti effect, or reactive power flow.
Most study material and work experience is distribution-centric, so the candidate defaults to the familiar model. The candidate also under-uses the power-flow relationships (P = EV sinδ / X, Q = (EV cosδ − V²)/X) and tries to reason qualitatively instead.
What to do instead
Memorise the two power-flow equations and the conditions under which line charging matters (long lines, light load, high voltage). For each transmission problem, state whether the line is short, medium, or long and which model applies before computing. Drill problems on voltage regulation and Ferranti effect until the distinction is automatic.
The candidate reads a code or standard question and answers from memory of a similar clause, without identifying which edition or which article governs, and without checking the exception or the definition section.
Code questions are deliberately built around exceptions, definitions, and cross-references. The candidate studies the main rule and skips the fine print, and under exam pressure recalls the general principle rather than the exact requirement.
What to do instead
For each code topic, build a one-page map: article number, the main rule, the key exception, and the definition that controls it. When practising, always locate the clause in the referenced standard before answering, and note which edition the exam uses. Treat definitions as examinable content, not background.
The candidate omits or misapplies earthing and bonding requirements - treating the earth electrode resistance as the sole fault-path guarantee, confusing equipment grounding conductor sizing with phase conductor sizing, or missing the requirement for protective equipotential bonding.
Earthing is taught conceptually as 'connect to earth' without the fault-loop and touch-voltage reasoning behind it. The candidate does not distinguish between the fault-current return path and the equipotential bonding function, so the two get merged.
What to do instead
Draw the fault loop for each system configuration (TN, TT, IT) and identify every conductor in the loop and its impedance. Learn the separate sizing rules for protective conductors and the purpose of main equipotential bonding. Solve touch-voltage and disconnection-time problems to see why the loop impedance, not the electrode resistance, drives compliance.
The candidate treats an ethics question as a general 'be honest' prompt and gives a vague answer, instead of identifying the specific duty owed (to the public, the client, the employer, or the profession), the conflicting obligation, and the required disclosure or withdrawal step.
Ethics content is often skimmed because it feels subjective, so the candidate never learns the decision framework. The candidate also misses that many scenarios turn on a specific procedural duty - such as disclosing a conflict, refusing to seal work outside competence, or reporting a danger to the public - rather than on general integrity.
What to do instead
Build a decision template: identify the parties, the competing obligations, the paramount duty (public safety and welfare first), then the required action and disclosure. Practise scenario questions by naming the duty and the procedural step explicitly. Memorise the rules on sealing, competence, conflicts of interest, and confidential information.
On engineering-management questions, the candidate answers from personal workplace habit rather than from the contractual and legal framework - for example, treating a verbal instruction as authoritative, ignoring the notice requirements in a contract, or confusing the roles of the engineer, the contractor, and the client's representative.
The candidate's day-to-day experience may be informal, and management topics are studied last and lightly. The candidate also conflates project controls (schedule, cost) with contractual administration (variations, claims, notices, certification).
What to do instead
Learn the standard contract administration cycle: instruction, notice, variation, claim, certification, and payment. For each management question, identify which party holds which role and which written record is required. Study the standard forms of contract used in the jurisdiction and practise variation and delay-claim scenarios.
The candidate spends disproportionate time on one hard calculation, leaves several questions unanswered, and then loses marks on easy recall items that would have been quick wins.
Exam technique is rarely practised under timed conditions, so the candidate has no sense of the per-question budget. The candidate also equates difficulty with importance and refuses to abandon a problem once started.
What to do instead
Do full timed mock exams with a strict per-question time budget and a hard rule: if a calculation exceeds its budget, mark it, move on, and return only after all easy items are answered. Track which question types overrun and drill those separately. Never leave a blank - a reasoned guess beats an empty answer.