Construction and Maintenance Electrician · Red Seal 309A
Five 309A practice test questions, answers included.
Five questions from five different work activities — recall, procedural and critical-thinking, the way the exam is built. Pick an answer, then open the explanation. Every question in the bank explains all four options, not just the right one.
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40 free 309A questions in all
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An operator's HMI reports 'communication error' with the PLC. At the PLC, the Ethernet port's link LED is off. Where does the diagnosis start?
- At the HMI's communication driver and node settings.
- At the PLC program, checking its communication instructions.
- At the physical layer: cable, connectors and switch port.
- At the PLC's IP address and subnet mask settings.
Show the answer
C. Correct. A dark link LED means the port sees no carrier from the other end; the cable is unplugged, damaged, terminated wrong or the switch port is dead or powered off. IP addressing, protocol settings and the program are irrelevant until the link comes up. Swapping in a known-good patch cable is a quick first test.
Source: Red Seal Occupational Standard, sub-task D-25.02
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A Class 2 transformer supplies the thermostat circuit of a furnace. Why does the CEC require the thermostat conductors to be separated from the 120 V furnace conductors?
- A power-conductor insulation failure could put 120 V on the Class 2 wiring.
- The 120 V conductors would induce enough voltage to trip the furnace control.
- The Class 2 voltage would feed back into the 120 V furnace wiring.
- The furnace conductors need the whole box fill allowance.
Show the answer
A. Correct. Class 2 wiring uses light insulation and no overcurrent protection sized for power circuits, so a power conductor's insulation failure would energize the thermostat wiring at 120 V. Rule 16-212(1) requires Class 2 conductors to be kept at least 50 mm from power or Class 1 conductors at 300 V or less (600 mm above 300 V) unless the power circuit is in a bonded metal raceway, armoured cable, non-metallic-sheathed cable (300 V or less) or non-metallic conduit, and Rule 12-3030 keeps conductors of different sources out of the same box unless a barrier divides it.
Source: Red Seal Occupational Standard, sub-task B-15.01
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A journeyperson tells an apprentice to 'pull the home run first'. In trade terminology, what does the home run refer to?
- The bonding conductor that returns to the service ground.
- The run from a switch box to the luminaire it controls.
- The run from the circuit's first box back to the panelboard.
- A feeder from the utility transformer to the service equipment.
Show the answer
C. Correct. The home run is the circuit's feed from the panel to the first box; the rest of the circuit daisy-chains from there. Pulling it first lets the circuit be identified and terminated at the panel while the branch wiring continues. Labelling the home run at the panel during rough-in saves tracing it later.
Source: Red Seal Occupational Standard, sub-task A-6.01
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A feeder must run exposed along the exterior wall of a warehouse, where it is exposed to rain and to occasional mechanical contact. Which cable is appropriate?
- AC90 armoured cable.
- TECK90 cable.
- NMD90 cable strapped to the wall.
- NMWU cable in a metal trough.
Show the answer
B. Correct. TECK90 has an inner jacket, interlocked armour and a PVC outer jacket, so it is rated for wet, outdoor and many hazardous locations and resists mechanical damage. The outer jacket is what keeps water off the armour; without it the armour corrodes and moisture reaches the conductors. ACWU90 is a similar wet-location armoured cable.
Source: Red Seal Occupational Standard, sub-task C-16.01
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A fire alarm panel reports a ground-fault trouble that appeared after a renovation. How is the faulted circuit located?
- Insulation-test every circuit with its field devices still connected.
- Measure each circuit's loop resistance to find the one out of range.
- Inspect devices in the renovated area and replace any that look damaged.
- Lift circuits one at a time until it clears; test that one to ground.
Show the answer
D. Correct. The panel senses leakage from its circuits to ground but cannot say which one. Isolating circuits in turn identifies the affected one; a resistance test from each conductor to ground (with devices considered) then leads to the damaged cable, typically pinched at a box, nicked by a screw or wet in a junction box. Starting with the circuits altered in the renovation usually finds it fastest.
Source: Red Seal Occupational Standard, sub-task E-26.02
Want ten more with every option explained? Free 309A practice questions — no account, no email, printable. With five more on each exam block page below, that makes 40 free 309A questions in all.
The 309A exam at a glance
How many questions are on the 309A Red Seal exam?
The Red Seal Construction Electrician (309A) exam has 100 multiple-choice questions, a 4-hour writing time and a 70% pass mark, spread across five major work activities. Between 60 and 70 percent are procedural and application questions. Sources: the Red Seal Program's exam information page and Exam Preparation Guide, checked October 21, 2026.
Question mix — weighted to the blueprint
Roughly one question in ten asks you to state a fact. Two-thirds ask you to apply a procedure, select or size something correctly, or follow a code rule, and the rest ask you to work a calculation or a fault through to a conclusion — which is exactly where recall-only question banks leave you exposed.
The full 309A practice exam
Know your Electrician score before exam day.
Free, Red Seal–style practice for the 309A Construction and Maintenance Electrician certification. Every test is weighted to the official exam blueprint — two-thirds procedure and application — so your score shows where you stand on each part of the exam.
What the 309A covers
Five major work activities.
The occupational standard groups the trade into five major work activities, 28 tasks and 97 sub-tasks. The question counts below are the official blueprint weightings — our 550-question bank is built to that same map, with every sub-task covered.
- A
Common occupational skills · 11 questions
Safety and lock-out, tools and meters, drawings and planning, support structures and seismic restraint, commissioning, communication and mentoring. Free block A questions: safety, tools and commissioning →
- B
Generating, distribution and service systems · 28 questions
Services and metering, overcurrent, ground-fault and surge protection, distribution equipment, UPS and power conditioning, grounding and bonding, generators, renewables, high voltage and transformers. Free block B questions: power distribution and grounding →
- C
Wiring systems · 30 questions
Conductors, cables, conduit, raceways and boxes; luminaires, devices and lighting controls; HVAC and electric heating wiring; exit and emergency lighting; cathodic protection. Free block C questions: wiring, lighting and heating →
- D
Motors and control systems · 21 questions
Starters and control circuits, AC and DC drives, single-phase, three-phase and DC motors, and PLC and automated control systems. Free block D questions: motors, drives and controls →
- E
Signalling and communication systems · 10 questions
Fire alarm, security and surveillance, structured cabling and CATV, PA and intercom, nurse call, and building automation and control systems. Free block E questions: fire alarm and communication systems →
Where our numbers come from
Code questions, checked against the code.
Code requirements are where practice banks quietly go wrong: a rule number remembered from an older edition, a table value that has since changed, a U.S. rule presented as Canadian. Every question in our 309A bank that depends on a code requirement was checked against the 2024 Canadian Electrical Code as adopted in the Ontario Electrical Safety Code, and the rule number is recorded question by question. Where a question would need a table value, the question supplies it and tests the method — the correction, the deduction, the selection — instead of memory. The formula sheet and acronym list are provided at the exam sitting, so we never test recall of those either. The question counts above are the Red Seal Program's own exam breakdown for Construction Electrician, and every question is mapped to a sub-task of the Red Seal Occupational Standard. For what each block covers and where to spend your study time, read the 309A exam guide. Read how our questions are made.
Tools for this exam: the free voltage drop calculator, conduit fill calculator and Ohm's law calculator, no account needed.
Edited by Trevor Mulder · Last checked against the Red Seal Program's published exam information.
Why practice scores mislead
You can ace recall and still fail the 309A.
Most question banks drill what you can recall, because recall questions are cheap to write. The 309A is the opposite — 5 to 15 percent recall, and the rest procedural and critical-thinking questions that ask you to size a conductor, count a box fill, or reason from a set of readings to a cause. That gap is why people walk in confident and walk out surprised. TicketPrep weights every test to the published blueprint, so a weak section here is a weak section there.
How TicketPrep prepares you
Built like a study tool, not a quiz app.
Weighted to the blueprint
Every test matches the published 309A weightings — heavy on the procedural questions the published exam breakdown calls for.
Every answer explained
Learn why the right answer is right — and why each of the other three is wrong. That's where the learning happens.
Timed mock exams
Full-length tests that match the real 100-question count and 4-hour limit, so exam day feels familiar.
Know your weak areas
Your score broken out by work activity, so you always know which section to drill next.
309A questions
Before you start.
How many questions are on the 309A Red Seal exam?
Is the 309A practice exam free?
What does the 309A exam cover?
Are the code questions based on the Canadian Electrical Code?
Are these real 309A exam questions?
How does TicketPrep compare with other Red Seal practice tests?
Find out where you actually stand.
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