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The full 309A bank is 131 questions across five topic areas. Two of them — code and theory — ask for completely different skills, and that shapes how you should study. What each holds, and what apprentices get wrong:
CEC Code — 36 questions. The largest block. Ampacity and correction factors, conductor and box fill, bonding and grounding, overcurrent protection, demand factors in service calculations, and the rules attached to particular locations. These are lookup questions: find the right table, then apply the right correction, in that order. The most common failure is stopping at the base ampacity value and never applying the ambient correction and the bundling derate. The second is terminal temperature rating — a conductor rated for 90°C landing on a terminal rated for 75°C is limited by the terminal.
Electrical Theory — 29 questions. Ohm's law and power in DC and AC, series and parallel networks, voltage drop, single- and three-phase relationships, power factor, transformer ratios and connections, and inductive and capacitive behaviour. In three-phase the recurring error is applying the √3 factor in the wrong place, mixing line and phase values between wye and delta. Voltage drop is the other: apprentices use the one-way run length instead of total circuit length, and land a conductor size low.
Motors & Controls — 28 questions. Motor types and characteristics, starting methods from across-the-line through reduced voltage, soft start and VFD, overload against short-circuit protection, control circuits, ladder diagrams, relays, contactors and timers, and troubleshooting from the print. The real gap is reading a ladder diagram in sequence: plenty of apprentices can name every component and still cannot say what happens when the stop button is pressed mid-sequence. Overload sizing is the other frequent miss — protection comes off the motor nameplate full load amps, not the table value used to size the conductor.
Wiring Methods — 22 questions. Selecting cable and raceway for the environment, supporting and securing, bending radius and fill, boxes and enclosures, cable tray, and terminations. Misses cluster in two places: which method is permitted where — fine in an accessible ceiling is not fine in a plenum, a wet or a hazardous location — and support spacing, which most people know for the one method they install every day and guess at for the rest.
Electrical Safety — 16 questions. Lockout and tagout, arc flash and shock approach boundaries, PPE selection, testing for absence of voltage, working near energized equipment, and utility clearances. The most-missed item is the test-before-touch sequence: proving the tester on a known live source before and after is what makes the reading trustworthy, and any answer dropping either step is wrong.
Sit the 50 timed, in one block, and keep the code book shut on this first pass — yes, even for the code questions, because the point is to separate what you know from what you can find. Put a dot beside every question you guessed at, then score it twice: the ones you got wrong, and the ones you got right with a dot. Guessed-right answers are misses that have not happened yet.
Sort the pile by topic, because for 309A the topic tells you which of two very different practice methods you need. Code is a speed and navigation skill: re-work your CEC misses with the actual code book, against a clock. You are training which section to turn to, and remembering every correction factor before answering — reading code like prose builds none of that. Theory is the opposite: work those with the book shut, on paper, until the relationships come back unprompted. Motors & Controls misses usually mean diagram reading, not facts — trace the ladder logic contact by contact and narrate what closes when. Wiring Methods and Safety misses are discrete rules; flashcards work.
This mock exam is a 50-question slice. The 309A Complete Question Bank has all 131 questions with a full explanation for every answer, organized by the published occupational standard topic areas, in one printable offline PDF.
Get the 309A Question Bank — CA$24 →The published examination weightings tell you where the marks sit. On the Construction Electrician examination weightings page, the interprovincial exam is described as 100 questions across five Major Work Activities: wiring systems at 34%, generating, distribution and service systems at 26%, motors and control systems at 18%, common occupational skills at 12%, and signalling and communication systems at 10%. The Red Seal exam preparation guide sets out the rest: four-option multiple choice, one correct answer worth one mark, four hours of writing time, and a 70% pass mark. Provincial and territorial authorities administer it, so confirm the arrangements for your jurisdiction.
These figures are current as of August 2026. Red Seal has published a new occupational standard for this trade and exams built on it are under development, so the question count and the weightings will change once those exams come into use. Check the trade page at red-seal.ca before you book.
Worth being straight about the difference: the standard organises by work activity, we organise by the skill a question demands, so code rules and theory spread across every activity there sit in their own blocks here. The gap to watch is signalling and communication systems: 10% of the published weighting, and this bank has no dedicated block for fire alarm, data and communication work — study that elsewhere.
Do I need the code book to use it? For theory, motors and safety questions, no. For the CEC Code block, open it after the first timed pass — the explanation gives the reasoning, but the point of that practice is training your hands to find the section.
Which code edition are the questions based on? They are written around rules and relationships that hold across editions — how corrections stack, how a service calculation is structured, what governs a wiring method in a given location — rather than specific printed table values. Provinces adopt editions on their own schedules and add amendments, so confirm exact values against the edition in force where you work.
How is 309A different from 442A industrial electrician? Construction electrician work centres on installation in buildings: services, distribution, branch circuits, wiring methods and the code rules governing them. Industrial electrician work leans into maintaining and troubleshooting plant equipment, instrumentation and process control. The two overlap in theory, motors and safety.
Is 50 questions enough to tell me anything? Enough to show where you are weak — not enough to tell you that you are ready, and no 50-question sample is.
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Independent, unofficial study resource — not affiliated with or endorsed by the CCDA, the Red Seal Program, or any provincial/territorial apprenticeship authority. All questions are original works. No guarantee of results.