Based on the Red Seal 309A standard & the Ontario Electrical Safety Code
About the certification
The 309A Construction & Maintenance Electrician Certificate of Qualification (C of Q) is Ontario's trade certification for electricians who install, alter, repair, and maintain electrical systems in buildings and structures. Trade certification is administered by Skilled Trades Ontario.
Construction Electrician is a Red Seal trade (Red Seal code 309A), so Ontario uses the interprovincial Red Seal Construction Electrician exam — 100 multiple-choice questions with a 70% pass mark and up to four hours to write. Passing earns both the provincial C of Q and the Red Seal endorsement recognized across Canada.
Exam questions are built from the Red Seal Occupational Standard (RSOS) and weighted by Major Work Activity, and installation work must comply with the Ontario Electrical Safety Code (the 2024 / 29th edition, based on CSA C22.1:24, in force since May 1, 2025). ExamHub's free 309A practice quiz has 126 original questions across the five exam blocks, written from these standards and established trade theory.
What's covered
Try a few
Five questions pulled from the full bank, with the answer shown — use the quiz above for the real timed experience.
Why: Synchronous speed = (120 × frequency) ÷ number of poles = (120 × 60) ÷ 4 = 1800 r/min. The actual rotor speed is slightly less because of slip.
Why: No. 14 AWG copper is rated 15 A, No. 12 AWG is 20 A, and No. 10 AWG is 30 A for up to three conductors in a raceway or cable.
Why: The Code sets a minimum consumer's service and feeder rating of 100 A for a single dwelling, ensuring adequate capacity for modern household loads.
Why: Swapping any two of the three line leads reverses the phase rotation of the stator's rotating field, reversing the motor. Swapping all three would not change rotation.
Why: The end-of-line resistor lets the panel monitor a small supervisory current. If a wire breaks, the current stops and the panel signals a trouble condition, ensuring circuit integrity is watched.
FAQ
The Ontario 309A Certificate of Qualification exam is the interprovincial Red Seal Construction Electrician exam — 100 multiple-choice questions, each with four options. ExamHub's practice bank has 126 original questions so you always see fresh ones.
Ontario certifying exams require 70% to pass. You generally have up to four hours to complete the exam.
The Red Seal exam breakdown weights five Major Work Activities: common occupational skills (about 11%), generating/distribution/service systems (about 28%), wiring systems (about 30%), motors and control systems (about 21%), and signalling and communication systems (about 10%).
Skilled Trades Ontario administers trade certification in Ontario. Construction & Maintenance Electrician (309A) is a Red Seal trade, so passing the exam earns both your provincial Certificate of Qualification and the interprovincial Red Seal endorsement. Licensed electrical work is regulated separately by the Electrical Safety Authority (ESA).
No. These are original questions written by ExamHub from the Red Seal 309A standard, the exam breakdown, and the current Ontario Electrical Safety Code (2024 / 29th edition). They cover the same topics but are not copies of any real exam question, and this is unofficial study practice only.