When any alarm detects a fire, it sends a 9-volt signal on the red wire. Any alarm that detects a 9-volt signal on the red wire will begin sounding its alarm immediately. Most alarms can handle about a dozen units intercommunicating on the same red wire. It’s a very simple and a very effective system.

What is the voltage on a hard wired smoke detector?

A hard-wired smoke alarm or carbon monoxide alarm is connected to other detectors throughout your home. These alarms sound simultaneously, on all levels of your home, when a single unit detects smoke or gas. All the units are wired to a 120-volt household electrical circuit and each have a battery backup.

Can you mix and match hard wired smoke detectors?





Absolutely! You can mix and match hardwired First Alert, BRK, and Onelink models. All of our current models use the same wiring harness and connector. We do not recommend mixing different brands since we can only guarantee the performance of First Alert and BRK alarms.

How do hardwired smoke detectors communicate?

Hardwired interconnection uses the wiring in your home to link AC-powered alarms together. The alarms communicate with each other via DC signal in the orange wire, which we call the Interconnect wire. The same fuse or circuit breaker in the home powers all interconnected units.

What is the input voltage of smoke detector?

Photoelectric Smoke Detector, Voltage: 12-35 V DC

Usage Office Buildings, Industrial Premises
Input Voltage 12-35 VDC
Alarm Current 40-80 mA


Are smoke detectors high or low voltage?





Thousands of lives are saved every single year through the use of properly functioning smoke detectors. High voltage smokes may also be referred to as 110-volt smoke detectors. As the name implies, these devices receive power from a high voltage network.

What is the minimum voltage for fire alarm?

UL (Underwriters Laboratories) 864, 9th Edition Standards for Fire Alarm Control Panels: All panels must have a demonstrated 20.4 VDC panel cut off voltage.

Can you interlink different smoke alarms?

Generally, the process for interlinking hardwired alarms is the same. Firstly, you need to make sure that the alarms you are purchasing are compatible with each other, as alarms from different manufacturers (in most cases) do not mix.

Can you mix ionization and photoelectric smoke detectors?

Can you mix ionization and photoelectric smoke detectors? Mixing the use of both photoelectric and ionization detectors is recommendable. The main reason is that the mix offers the best protection from all types of fires. It’s important to note that there are single units with both technologies.

Can I Interlink my existing smoke alarms?



You can use either sealed battery alarms or mains-wired alarms. Both types of alarm are interlinked by radio frequency and do not need WiFi.

What is the output of a smoke detector?

The true duct smoke detector analogue output status levels is 2-10 Vdc. 2 Vdc means sensor fault, 3-7 Vdc means normal operation, 7-9 Vdc means optics needs cleaning and 9.5 V dc means smoke alarm.

What is the output of an automatic smoke detector?

Input Devices – Smoke detectors and alarm call points that will trigger the alarm. Output Devices – The alarm sounder, including bells, sirens and flashing lights etc. Control Equipment – monitoring of the system, status and fault finding, silencing and resetting the alarm.

How much current does a smoke detector draw?



A battery operated ionisation smoke alarm typically draws less than 100 µW (or 0.1 mW). A small power increase is required for a fraction of a second to power a pulsing LED once every 10 to 60 seconds.

How do you wire a low voltage smoke detector?


Quote from Youtube video: Pick the first positive in the first negative. So we just slide the wire in. And then tighten it down. And then the negative wire. Into the third terminal or the first negative tighten that one down.

Can you use a hardwired smoke detector with just a battery?

Most fire experts just want working smoke alarms, but hardwired is a great choice in spaces that have wiring. If not, we strongly recommend a battery-only with a built-in 10-year battery.”

Will a hard wired smoke detector work without a battery?

Smoke Alarm Power Sources



Without the battery, neither of these units has the power to go off. Other smoke detectors get hardwired, meaning they tap into and draw their power from the home or building’s electricity. Hardwired alarms often have a battery backup just in case the electrical power goes out.

Why do hardwired smoke detectors go off when power goes out?



Linked smoke detectors function on the 120-volt AC electrical system that is hardwired into a building or residence. Most have backup batteries to power the smoke alarms in the event of a power outage. Hardwired smoke alarms are vulnerable to power surges, which may cause them to fail temporarily or even permanently.

Why do hard wired smoke detectors go off for no reason?

The most likely reason smoke detectors go off unexpectedly is that people aren’t changing the batteries in them often enough. In most sensors you might think of, the strength of the signal goes up when they detect what they’re supposed to. Common causes of smoke detector false positives around the house.

Why is my hard wired smoke detector beeping no battery?

If your hardwired machines continue to beep in the absence of a battery, it’s most likely because the backup battery has become active. Keep in mind that a backup battery unit is only available with a hardwired device, so if your smoke alarm is battery-only, the chirping is coming from somewhere else.

How do you reset a hardwired smoke detector?

Resetting the Alarm

  1. Turn off the power to the smoke alarm at the circuit breaker.
  2. Remove the smoke alarm from the mounting bracket and disconnect the power.
  3. Remove the battery.
  4. Press and hold the test button for at least 15 seconds. …
  5. Reconnect the power and reinstall the battery.



Why is my hardwired smoke detector blinking red?

The Batteries are Low: Usually accompanied by a loud beep, a blinking red light could mean the batteries in the unit are low. Consider adding fresh batteries and running a test to make sure it’s working. It Needs to Be Replaced: Smoke detectors don’t last forever.