Do smoke detectors need to be hardwired?

Do smoke detectors need to be hardwired?

Installation of smoke detectors

In fire detection we always highlight its main components: detectors, alarms, pushbuttons, etc. However, there is a key element, without which, in most cases, it would be impossible for the whole system to even work. We are referring to the wiring.

Basically, there are two types of cables for fire detection systems, according to one characteristic: their behavior in the event of fire. The first one refers to how it reacts to fire, i.e., what will be the behavior of an exposed material against the fall of flaming particles, the emission of heat and/or smoke, the propagation of flames, the increase of temperature, etc. The other consideration is how long the material will resist fire.

Although there are many regulations worldwide with respect to building materials, the European provisions being the most advanced, in elementary terms all cables comply with the same features worldwide.

Nfpa 72

It appears that CEC and NEC handle smoke detectors differently. CEC requires smoke alarms to be on a circuit with lights and if on an AFCI circuit the smoke needs an integral battery (which I understand as something that can’t be removed).

To get a new 3 wire backup, I would have to open the drywall at the bottom of the wall for 15 ‘. Drill through the corner studs and go through a door header (the previous wire is on the surface of the header that was shimmed for drywall and then had a large piece of metal as a nail protector 5′ wide x 3’ long. The drywall and trim is already painted and caulked.

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I spoke with Kidde tech support and the rep stated that the smoke detectors must be on their own circuit otherwise they would trip; clearly, that is wrong since CEC requires them to have lights on the same circuit.

Standard nfpa 72 smoke detectors

Smoke detectors can be connected to the mains. Some models also incorporate a battery-operated battery so that they do not stop working in the event of a power failure. They are also available wireless. In addition, you should know that carbon monoxide detectors have a chemical that helps the detection process so you should check it as well as the batteries.

In this article we focus on the location of the detectors for maximum efficiency. Detectors should preferably be installed on the ceiling, in a fixed position, in a place where their performance is efficient, taking into account that smoke always tends to rise. A separation distance of 9 meters (in an unobstructed space between the area to be protected and the detector) can be established between one detector and another.

The detectors must be placed in the center of the ceiling of the room, since it is where smoke and heat are concentrated. Respect a minimum distance of 50 cm between the location of the smoke detector on the ceiling and the wall.

Smoke detector

Why? I have an existing hardwired OneLink alarm and a battery-powered slave. But the corresponding hardwired BRK alarms get terrible reviews (see Passive-aggressive smoke detectors for the type of problem). I’d like to know if I can buy higher quality units and still interface them.

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Even if you plug them in and test them, and they seem to work, that is no substitute for the kind of testing the manufacturer or test lab would do. You cannot be sure what is going on in the electronics and whether a problem may develop in the future.

If a problem prevents the device from functioning properly, it may not be discovered until the worst possible time. With personal safety devices, it is best to follow the rules to the letter.

J MartinHi, my name is Josh and I install smoke detectors for a living (licensed electrician), and my experience is that smoke detectors of different brands can cause false alarms as the interconnect voltage can range from 5v to 9v dc. If they are interconnected, it is best if they are all the same brand. Now they are also using RF wireless interconnect, you can even use a combination of both. For example, Brooks https://www.brooks.com.au/home-smoke-alarms/battery-powered/wall-mount-test-locate-silence-memory-control-eib450/ even has a wireless remote control, great for high ceilings and elderly people. As for having hardwired alarms on different circuits, it is not a good idea as it tends to cause the RCDs to trip every time interconnected alarms go off and sound. Hope that helps.

Do smoke detectors need to be hardwired?
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