Smoke detectors are essential to keep your home and family safe. This is especially relevant when fires can begin quietly and go undetected until it is too late. However, hard-wired smoke detectors, which are common in most residential buildings, only work when there is a continuous electrical charge from the home’s electrical system.
While many homeowners try to substitute hard-wired smoke detectors with battery-operated ones, battery-operated smoke detectors can easily fail due to dead batteries. This is because they do not go through screening regularly. Therefore, having a hardwired smoke detector in a home ensures you’ll never be without a functional smoke detector.
What Is a Hardwired Smoke Detectors?

A smoke detector that is “hardwired,” means that it’s directly connected to your home’s electrical circuits, it is not “plugged in” to an electrical outlet.
Hardwired smoke detectors and battery-powered smoke detectors look the same. They are usually mounted on your wall or ceiling. However hard-wired smoke detectors have a constant electrical current that limits the possibility of failure unless the power goes out. If this happens the smoke detector will use its backup battery.
How to Install Wired Smoke Detectors
Turn Off the Power
Find the existing circuit on your home’s circuit breaker that powers your smoke detectors. Safety first!
Cut the Holes
Use a stud finder to locate the ceiling joist or wall stud where your smoke detector will be mounted. Use an electrical box as a template to trace around, so the hole is cut precisely. Cut a hole in-between the wall studs, use a level to ensure that the outline of the box is level.
Drill a pilot hole in the middle of the outline for the electrical box. And cut around the template outline. The electrical box should be snug in the drywall.
Run the Wire
From the power source, run the new electrical wire for the smoke alarms (with the ground) to the location of the detectors. You can use an existing power source such as an existing wall outlet. Remember to leave a good amount of excess cable extended through the hole in the drywall. This will make installing the smoke detector easier. That is because you will have enough wire to cut the proper length when installing the smoke detector.
If you’re installing multiple smoke detectors you’ll want to run a 3-wire cable (with the ground) from the first smoke detector to each subsequent smoke detector. The extra wire will allow each smoke detector to communicate with one another so that if one smoke detector detects smoke, all detectors will go off.
Attach the Wires to the Electrical Boxes
At each electrical box location, you’ll remove the insulating wrap from the wire using a cable stripper and clamp the wires to each electrical box.
Secure the Electrical Boxes
Once the cables have been secured to each box, you’ll secure the electrical box in the opening of the drywall. Feed the circuit wires through the smoke detector’s mounting plate and align the screw holes on the mounting plate to the hole in the electrical box. Using the screws that came with the smoke detector, secure the smoke detector in place.
Wire the Smoke Detector
The smoke detector has two parts: the alarm itself and the harness. The harness has wires that come out of it and plug into the alarm. You’ll connect the wiring harness with the black, white, and red wires coming through the nearest electrical box.
Put It All Together
Once your smoke detectors have been wired, you can attach the mounting plate to the electrical box with screws and attach the wire harness to the back of the smoke alarm. The notches on the back of the alarm align with those on the base, and with a quick twist, it is secured.
Connect to the Circuit
Once this is complete, pigtail the wires into the circuit and join the smoke detector cable to the circuit. Once you’ve joined the wires, you can restore power to the circuit by turning on the circuit breaker.
Need Help? Book With Pulled
Installing hardwired smoke detectors can be a complicated process and you may have a unique situation that makes installation even harder. If that happens, you can book an electrician to install your hardwired smoke alarm and carbon monoxide alarm systems for you. They can also discuss the option of using smart smoke detectors, to keep you connected and your home protected at all times.