Certifying authority: Skilled Trades Ontario (STO). Last checked 2026-09-10.
This trade is not on Ontario’s compulsory list, so you may work in it without a certificate. The Red Seal still travels across Canada as a recognised credential, and employers frequently ask for it — but in Ontario it is a qualification, not a licence.
Source: Skilled Trades Ontario — Compulsory Trades (23 trades)
Start with 10 free interactive Industrial Electrician (442A) questions with worked explanations, or take a full 100-question timed mock exam weighted to the official RSOS breakdown.
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Whether it is required or not, the exam itself is the same paper everywhere in Canada. What your province decides is whether you must hold the certificate, how you apply, and where you sit it.
The Red Seal Occupational Standard sets the split below. It does not change by province.
| Major Work Activity | Weighting | Questions |
|---|---|---|
| MWA A: Performs common occupational skills | 9% | 9 Qs |
| MWA B: Installs and maintains generating, distribution and service systems | 23% | 23 Qs |
| MWA C: Installs and maintains wiring systems | 20% | 20 Qs |
| MWA D: Installs and maintains rotating and non-rotating equipment and control systems | 21% | 21 Qs |
| MWA E: Installs and maintains signalling and communication systems | 10% | 10 Qs |
| MWA F: Installs and maintains process control systems | 17% | 17 Qs |
Source: Red Seal Exam Breakdown — Industrial Electrician (442A), red-seal.ca
4 hours, and a 70% pass mark (70/100). These are set provincially rather than by the Red Seal standard, and the four hours is the same whether your paper is 100 or 150 questions.
Confirmed against Skilled Trades Ontario’s Exam Preparation Guide and SkilledTradesBC. Check your own authority before exam day.
Click any option (A–D) below to grade yourself immediately and view the worked explanation:
Good industrial housekeeping requires immediate removal of tripping hazards from egress aisles, disposal of oil-soaked rags in approved self-closing metal oily-waste containers to prevent spontaneous combustion, and proper rack storage of materials. One open drum puts oily rags beside the scrap where they can ignite, a plastic bag does not contain the heat, and crates along the wall still narrow the aisle.
A megohmmeter (insulation resistance tester) applies a high DC test voltage (typically 500 VDC or 1000 VDC on 600 V rated cables) to detect insulation breakdown, moisture ingress, or high-resistance paths to ground. A rotation meter checks sequence, a clamp ammeter reads current, and a micro-ohmmeter reads very low resistance.
A closed mechanical switch should drop nearly 0 V. Measuring 120 V on the line side and 18 V on the load side (a 102 V drop across the contacts) proves high contact resistance inside Door Switch 2. A short to the frame would read near 0 V and blow a fuse, closed switches in series should drop almost nothing, and reversed conductors would not leave 18 V on one side.
Booking is handled by Skilled Trades Ontario (STO); confirm current locations and dates with them.
Our Industrial Electrician (442A) question bank is built to the official RSOS weighting above, with a worked explanation and code citation on every question.
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