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Smoke & CO Detectors: Buyer's Guide for Electricians and Contractors

Smoke & CO Detectors: Buyer's Guide for Electricians and Contractors

Code Requirements in Ontario (2024)

Smoke alarms and carbon monoxide (CO) detectors are governed by the Ontario Fire Code, Ontario Building Code, and the manufacturer's installation instructions. As of recent Ontario Building Code revisions:

  • Smoke alarms required on every storey including basements and sleeping areas.
  • CO alarms required adjacent to every sleeping area where a fuel-burning appliance, fireplace, or attached garage is present.
  • Interconnection required in new construction — when one sounds, all sound.
  • Hardwired with battery backup required in new dwellings with 3+ bedrooms or more than 2 storeys.

Detection Technologies

Ionization Smoke Alarms

Uses a small radioactive source (Americium-241) to ionize air inside a detection chamber. When smoke particles disrupt the ionization current, the alarm sounds. Ionization detectors respond faster to fast-flaming fires but are prone to nuisance alarms from cooking steam.

Photoelectric Smoke Alarms

Uses a light beam and photocell. When smoke particles scatter light into the photocell, the alarm triggers. Photoelectric detectors respond better to slow-smouldering fires and have fewer nuisance alarms. Recommended by fire safety organizations and increasingly required by code.

Dual Sensor (Combination)

Contains both ionization and photoelectric sensors. Best of both technologies. Examples: Kidde i12060, BRK 9120LBL. Increasingly preferred by inspectors and homeowners who want the broadest protection.

CO Detectors

Electrochemical CO sensors measure carbon monoxide concentration in parts per million. Alarm thresholds per UL 2034: 400 ppm in 4–15 minutes, 150 ppm in 10–50 minutes, 70 ppm within 60–240 minutes. Kidde and Kidde Nighthawk are the dominant brands in Canada.

Hardwired vs. Battery-Only

Hardwired: Connects to 120V AC with battery backup. Required in new construction. When one alarm triggers, all interconnected alarms in the dwelling sound simultaneously. Typical wire: 14/3 NMD90 for interconnect.

Battery-only: Permitted for replacement in existing installations where hardwiring is not accessible. 10-year sealed battery units (Kidde 10Y29) eliminate the need for battery replacement.

Combination Units

Combination smoke + CO alarms like the Kidde P4010ACSCO and BRK SC9120LBL save installation time and panel space. Popular for garage spaces, utility rooms, and anywhere both hazards are present.

Top Brands at Maple Electric Supply

  • Kidde: Most widely specified in Canada. Broadest selection of hardwired, battery, and combo units.
  • BRK / First Alert: Long track record, CSA approved, popular with contractors.
  • Ei Electronics: Premium brand with 10-year sensor life, popular in higher-end residential.

Smoke & CO Detectors at Maple Electric Supply

We stock hardwired, battery, and combination smoke/CO alarms from Kidde, BRK, and other leading brands. Same-day pickup at our Toronto location or next-day delivery across Ontario. Browse our fire safety collection or call our counter for code-specific guidance.