Smoke & CO Alarm Rules in BC (2025-2026): Interconnection, Secondary Suites, and What Inspectors Look For
- akaielectricltd
- Dec 13, 2025
- 4 min read
This 2025-2026 homeowner guide clarifies smoke and carbon monoxide alarm rules in British Columbia, how interconnection works in houses with secondary suites, and the specific carbon monoxide alarm requirements the City of Vancouver enforces. It also outlines what inspectors look for and how to pass on the first visit.
Let’s dive in!
Quick answer:
BC requires smoke alarms on every storey and near sleeping rooms. In suites, municipalities commonly require photoelectric alarms that are interconnected so that one alarm sets off all alarms.
In houses with secondary suites, interconnection rules depend on the fire-resistance rating between units. Many jurisdictions allow less fire-resistance when alarms are interconnected across both units.
Carbon monoxide alarms are required where a dwelling has an attached garage, fuel-fired appliance, or shares a wall or floor with a parking garage or a service room that contains a fuel-fired appliance. Vancouver requires CO alarms in these conditions for all dwelling units, new and existing.
Inspectors verify locations, interconnection, power source, labels, and audibility. Keep documentation handy and test interconnection during inspection.
At-a-glance: where alarms go and how they must work
Topic | BC requirement in practice | What to do at home | Where you will notice it |
Smoke alarm locations | One on every storey, in each sleeping room for new work, and in the hallway outside bedrooms | Add or replace with photoelectric units, verify locations meet current rules | Bedrooms, hallways, basements, finished attics |
Interconnection in secondary suites | Municipal guides based on BC Building Code require alarms in both units and common spaces to be interconnected so actuation of any one sounds all alarms | Use interconnect-capable hard-wired alarms, or approved wireless interconnect if permitted | Both the main dwelling and the suite, plus shared areas |
Fire-resistance vs interconnection trade-off | Many jurisdictions permit lower fire-resistance ratings when alarms are interconnected across units, or higher ratings when units are not interconnected | If you prefer not to interconnect between units, expect a higher fire-separation requirement | Ceilings and walls between suite and main dwelling |
CO alarm triggers | Required if there is an attached garage, any fuel-fired appliance, or a shared wall or floor with a garage or a service room containing a fuel-fired appliance | Install CO alarms within or near sleeping rooms, follow manufacturer placement limits | Bedrooms and nearby hallways |
Power supply and backup | New or renovated work is typically hard-wired with battery backup, existing homes may use battery or plug-in where allowed by bylaw | Replace expired units and match power type to your permit scope | At each alarm location |
Who qualifies in 2026
Homeowners creating or legalizing secondary suites, finishing basements, or renovating bedrooms.
Owners of houses or townhomes that include fuel-fired appliances or attached garages.
Vancouver homeowners, since the Fire By-law requires CO alarms in the listed conditions for all dwelling units, including older homes.
Dates, deadlines, and coordination tips
Confirm interconnection strategy before drywall. Interconnecting after finishes are complete is costly unless you use an approved wireless interconnect that your jurisdiction accepts.
Match device types. Where municipal guides call for photoelectric smoke alarms, do not mix ionization units.
Test and label. Press any test button and verify every alarm sounds. Label panel schedules and keep manuals and receipts with your permit file.
Stacking and special cases
Suites with different separations. Some municipalities allow 15-minute separation where every smoke alarm in the house is interconnected, 30-minute separation with additional interconnected photoelectric alarms, or 45-minute separation where alarms are not interconnected between units. Check the option you plan to use before you frame.
CO alarms in suites. If CO alarms are required in a house with a secondary suite, many municipalities require the CO alarms to be interconnected so that activation in one unit triggers the other.
Existing older homes. You can usually replace expired alarms one-for-one without opening walls. Any new wiring or renovation will need to meet current code for that scope.
How to proceed in 3 steps
For homeowners
Book a safety inspection to confirm locations, interconnection approach, and any suite separation options.
Home Electrical Safety Inspections
Select listed photoelectric smoke alarms and CO alarms that support interconnect or approved wireless interconnect. Keep packaging and manuals for the inspector.
Install to manufacturer spacing and height rules, test interconnection, and keep records for insurance and resale.
For secondary suites
Decide whether to interconnect between units or to increase fire-resistance between units.
Show your plan on drawings before permit issuance and confirm what your municipality accepts.
Coordinate electrical rough-in with framing and drywall so alarms and interconnects are in the right places.
Frequently asked questions
Do smoke alarms have to be hard-wired?
For new or renovated work, yes, hard-wired with battery backup is typical. Existing homes may use battery or plug-in units where a bylaw allows. Check your permit scope.
Do I need CO alarms if I have only electric appliances?
A CO alarm is still required if there is an attached garage or your dwelling shares a wall or floor with a parking garage or a service room that contains a fuel-fired appliance.
Do CO alarms have to be interconnected between the suite and main dwelling?
Where CO alarms are required in a house with a secondary suite, many municipal guides require interconnection so that activation in one unit sounds alarms in the other. Confirm with your local authority at intake.
What do inspectors look for on site?
Correct locations near bedrooms and on each storey, photoelectric type where required, interconnection test from any device, correct power supply and battery backup, labels and manuals available, and audibility through closed doors.
Make it easy with Akai Electric
We install and commission smoke and CO alarm systems that meet BC requirements and local bylaws. Our team handles permits and inspections for houses and secondary suites across the Lower Mainland.
Get a same-week safety assessment
Home Electrical Safety Inspections
Topic or claim | Official source |
Province overview of the BC Fire Code and compliance resources | |
City of Vancouver CO alarm requirement for all dwelling units where there is an attached garage, fuel-fired appliance, or shared separation with a garage or service room | |
City of Vancouver important notice summarizing CO alarm triggers and device types under the Fire By-law | |
Secondary suite interconnection and photoelectric smoke alarm requirements, province bulletin reference | |
Province bulletin describing secondary suite fire-separation options and interconnection trade-offs | |
CO alarm interconnection for houses with secondary suites in municipal guidance | |
Visual installation guide for alarms and interconnection in suites, updated for 2024 BCBC context |