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Hardwired smoke detectors: what you need
The hardwired smoke alarm: how it differs from a battery model, why alarms are interconnected, where they go, when to replace them and who installs them.
In short
This guide covers the hardwired smoke alarm, the one connected to the home’s power.
- A hardwired alarm is connected to 120 V; it can’t be replaced with a battery-operated model.
- According to the Government of Québec, hardwired alarms should be interconnected, so they all sound together.
- They are replaced every 10 years from the date of manufacture.
- The rules that apply in your home also depend on your municipality.
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Hardwired or battery
The Government of Québec distinguishes two types of smoke alarms: the hardwired alarm, connected to 120 V power, and the battery-operated alarm.
The hardwired alarm should also have a backup battery.
A hardwired alarm can’t be replaced with a battery-operated model.
Interconnected
Hardwired alarms should be interconnected: when one detects smoke, they all sound at the same time.
To have them interconnected, the Government of Québec advises contacting a qualified electrician.
In dwellings and single-family houses or homes of two storeys or less, Chapter I, Building, of the Construction Code required from December 13, 2016 interconnected alarms, supplied by a 120 V circuit, with a backup battery and a silence button, according to the CMEQ’s 2017 summary. That summary covers the edition that includes the 2010 National Building Code; later editions of Chapter I were not read for this guide.
The 2026 Code (Chapter V, Electricity) refers to the National Building Code for installing smoke and carbon monoxide alarms in dwellings.
Where they go
The Government of Québec recommends one alarm per storey, basement included, and one in every room where someone sleeps.
According to the CMEQ’s summary (Chapter I, 2010 edition), the Code required in dwellings and single-family houses or homes of two storeys or less:
- one alarm per bedroom;
- one alarm per storey in the hallways, basement included;
- a smoke alarm or a heat detector for the garage.
A carbon monoxide alarm is also required if there is a gas or wood fireplace, or a garage attached to the house; a combination model is allowed.
These requirements apply to construction and to work covered by the Code. For an existing house, check with your municipality, as the Government of Québec recommends.
When to replace them
Smoke alarms are replaced every 10 years from the date of manufacture.
A hardwired alarm is replaced with another hardwired alarm, not with a battery-operated model.
Replacing a hardwired alarm is electrical work: in Québec, it goes to an electrical contractor.
The City of Winnipeg gives a word of caution: a hardwired alarm shouldn’t be on a circuit being modified, unless it has a backup battery. See Arc-fault breaker.
Alarms to interconnect or replace?
We install them when we redo a basement or a room. The exact price is written in the quote.
Send my quote requestWhy it beeps
An intermittent beep means the battery needs to be changed, according to the Government of Québec. A hardwired alarm also has a backup battery.
What we do
When we redo a basement or a room, we install the circuits, the outlets and interconnected smoke alarms, at the pace of your project.
The quote is written and free. If we find something when we open up, we call you before going further.
Frequently asked questions
Do I need an electrician to replace a hardwired smoke detector?
Yes: in Québec, electrical work is reserved for electrical contractors, even for an outlet. And a hardwired alarm can’t be replaced with a battery-operated model.
When should a hardwired smoke detector be replaced?
Every 10 years from the date of manufacture, according to the Government of Québec.
Why is my smoke detector beeping?
An intermittent beep means the battery needs to be changed; a hardwired alarm also has a backup battery.
Do smoke alarms have to be interconnected?
The Government of Québec recommends interconnecting hardwired alarms. According to the CMEQ, the Code (Chapter I, 2010 edition) required it from December 13, 2016 in dwellings and single-family houses or homes of two storeys or less.
Alarms to interconnect or replace?
We install interconnected smoke alarms when we redo a room; the exact price is in the quote.
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Sources
Consulted on October 30, 2026.
- Government of Québec, Smoke alarms (in French)
- CMEQ, Informel, January 2017: changes to Chapter I, Building, of the Construction Code (in French)
- Association de la construction du Québec, Smoke alarm technical sheet (in French)
- Gazette officielle du Québec, March 11, 2026, Order in Council 236-2026 (Construction Code, Chapter V) (in French)