How To Replace A Hard-Wired Smoke Detector

A guide to safely updating your smoke alarms. 


September 4, 2020

2 61 How-To-Replace-A-Hard-Wired-Smoke-Detector Desktop

2020 Update

Although this article is over a year old, all of the information is still relevant. It can be important to know how to replace a hard wired smoke detector; scroll down to find out how. 

Aside from the obvious benefit of never hearing the irritating and constant ‘chirp’ of a low or faulty battery, a hard-wired smoke detector provides a greater level of safety for your family.  A dead battery puts you at risk, while smoke detectors powered by electricity (with battery backups) will fulfill home safety and fire regulations. Another benefit of a hard-wired smoke detector is its ability to interface with your monitored home security system.  Monitored smoke detectors  not only sound an alarm, but they will also contact the fire department. A quick response to household or business fires can help save lives and property.

Keep in mind that like all mechanical and electrical home products, they have a certain life cycle and may fail eventually. The  Consumer Reports Agency  states that smoke detectors should be fully replaced after 10 years, as that’s when their sensors will start to lose their sensitivity, putting your home at risk.

Before Replacing Your Hard-Wired Smoke Detector

Replacing your hard-wired smoke detector means you’re about to handle electrical work. Therefore, the procedure should be done with caution and thorough attention to detail. If possible, refer to your smoke detector’s user manual. If you run into additional questions or are unsure about something, seek confirmation before continuing the task. You can also find guidance by calling your smoke detector’s manufacturer.

How To Replace A Hard-Wired Smoke Detector

First, make sure you shut off the power to the detector’s circuit at the main electrical panel. Then, unscrew the old detector from it ceiling or wall mount. After that, take note of the three wires as you detach them from the old smoke detector: black = 120V Power, white = Neutral, and red or yellow are the interconnecting circuit wires. Keep in mind, if the wires are contained within a plastic plug, detach the plug, then remove the old mounting plate and any wire harness connected to your home wiring. After that, install the new wire harness by matching the connections to the black, white, and red house wires. Then, twist the metal wires to make a good connection and secure with electrical tape or wire caps.

NOTE: For two-wire detectors – connect the black to black, and white to white. Then screw the new mounting plate in place and bring the newly attached wiring harness out. Attach the new smoke detector plug to its receptacle from the wall/ceiling and install the backup batteries in the new smoke detector head and screw onto base. Next, turn the power back on and test the smoke detector via its “test” button.

How Often Should Hard-Wired Smoke Detectors Be Replaced?

As mentioned before, smoke detectors should be replaced every 10 years. After about a decade, your sensors will become weak and less efficient, which makes it less likely for them to perform their most basic function: detecting smoke in your home. Even if your detector is older than 10 years and seems to respond to the routine test applications, you will still need to replace the device. The smoke detector’s test buttons may only be confirming that other components within the device (such as the battery, electronics, and alert system) are working. Finally, if you just moved into a new home with a pre-existing smoke detector, call a technician to verify the age of your device.

Complete Fire, Safety, and Theft Protection

While replacing your hard-wired smoke detector is pretty straightforward, protecting your property and family can sometimes seem overwhelming. Brinks Home™ delivers dependable and comprehensive home safety services. Contact us  to discuss a monitored home security system which can include smoke detectors, 24/7 in-home surveillance, door and window sensors, and motion detectors – all delivered with an easy DIY installation package or set up by trained professionals depending on your preference.

Lauren Slade is a Dallas-based writer and editor.

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