Do smoke alarms need to be on a dedicated circuit?

Asked By: Jovanny Fischerbauer | Last Updated: 11th May, 2020
Category: home and garden smart home
4.6/5 (1,233 Views . 38 Votes)
A smoke detector does not need to be on a dedicated circuit in most instances, but builders should consult local building codes to check any applicable regulations.

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Also, how many smoke detectors should be on a circuit?

A maximum of 18 compatible units may be interconnected (Maximum of 12 Smoke Alarms). The same fuse or circuit breaker must power all interconnected units. The total length of wire interconnecting the units should be less than 1000 feet (300 meters).

Also Know, are all smoke detectors on the same breaker? Assuming they were installed correctly, are the 6 identical smoke detectors in my house on the same circuit? Normally yes, but it doesn't necessarily have to be that way. If they're the newer interconnect then it's easier to simply loop one line throughout the house (people almost always take the easy way out).

Keeping this in consideration, can you wire smoke alarm to lighting circuit?

Mains Powered Smoke & Heat Alarms – hard-wired interconnection. All of Aico's mains powered smoke and heat alarms again require a permanent 230V AC mains supply which can be taken from a local lighting circuit or a dedicated circuit at the distribution board.

How many amps does a smoke detector use?

These devices are typically connected to a 120-volt, single-phase, 15- and 20-ampere branch circuit and include battery backup within the smoke alarm.

35 Related Question Answers Found

How many smoke detectors can you have in one zone?

number of smoke detectors is 20 pcs. per zone.

How many smoke detectors can you have in one loop?

Any conventional panel zone will be support up to 20 numbers of detectors. Loop word use in addressable panel. Loop detector capacity is depends upon panel manufacturer and its type of protocol. Some addressable loop support 525 devices or some support 126 devices,.

What is code for smoke detectors in a house?

For many years NFPA 72, National Fire Alarm and Signaling Code, has required as a minimum that smoke alarms be installed inside every sleep room (even for existing homes) in addition to requiring them outside each sleeping area and on every level of the home. (Additional smoke alarms are required for larger homes.)

Can you interconnect different brands of smoke detectors?

When there is an actual alarm, the unit that detects the smoke triggers all the others to sound an alarm. Different manufactures use different signalling schemes for this common wire. Other units may or may not work together, or may mix up a smoke alarm versus a carbon monoxide alarm, so don't mix them!

What wire is used for smoke detectors?


The smoke detectors are hardwired as follows: 120VAC power is provided by the hot (black) and neutral (white) wires. Interconnect alarm signaling is carried by the red wire. If one alarm is triggered, it will signal the other alarms to sound.

What circuit are smoke detectors on?

A hard-wired smoke alarm or carbon monoxide alarm is wired to a 120V household electrical circuit and is connected to other detectors throughout your home.

Do smoke detectors have to be wired in series?

Hard-wired smoke detectors are connected in a series to provide a warning to every part of a home or building. Once one of the alarms goes off, the others follow. These detectors are connected to a power source all the time to ensure maximum protection.

Do I need an electrician to replace hardwired smoke detectors?

They are hard-wired into our electrical system, but that doesn't mean you need an electrician to replace them. Modern hard-wired smoke detectors don't have wires in the back that need to be connected to loose wires in the ceiling.

How do you test a fire alarm wire?

Press and hold the test button on the smoke detector. It can take a few seconds to begin, but a loud, ear-piercing siren should emanate from the smoke detector while the button is pressed. If the sound is weak or nonexistent, replace your batteries.

Can you spur off a smoke alarm?


You can spur off with a joint box in the loft, making sure you connect the L N and interlink through tot he new one correctly (as cable colours may be different if original install was older). The additional smoke alarm would need to be the same make as the ones installed - Most are not compatible with each other.

How do you install a hard wired smoke detector?

  1. Cut holes for remodel boxes. • Identify where the smoke alarm will be installed.
  2. Run cable to the first alarm. •
  3. Install next runs of wiring. •
  4. Secure the cable and set the box. •
  5. Strip the wires. •
  6. Wire the alarm. •
  7. Attach mounting plate. •
  8. Attach alarm to the base. •

Can you unplug a hard wired smoke detector?

If there are connecting wires, it is a hard-wired unit and the wires can be disconnected. Dismount from the ladder and flip the circuit breaker switch that controls the smoke detector. If there is no obvious marking on the panel that designates a switch for the detector, throw the main breaker to the "Off" position.

How do you disconnect a hardwired smoke detector?

The steps are pretty simple:
  1. Turn off the power.
  2. Give your smoke alarm a twist to loosen it.
  3. Disconnect your smoke alarm from the wiring harness.
  4. Loosen the screws that hold the mounting bracket in place.
  5. Remove the mounting bracket.
  6. Disconnect the old wiring harness from the existing wires.

How do you change the battery in a hard wired smoke detector?

To replace the battery in your hard-wired smoke detector, follow these steps:
  1. Turn off power to your wired smoke detector at the circuit box.
  2. Find the battery cover panel on the detector.
  3. If there's a screw holding it in place, use the screwdriver to remove it.
  4. Remove the old battery and replace it with a new one.

Do you have to turn off power to change smoke detector?


Many residential smoke alarms connect to the home electrical system as well as a battery. The battery serves as a backup should the power go out. When you need to service or replace the alarm, you should turn off the power.

How do you reset a 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.

How do you turn off an electric smoke alarm?

Take the smoke detector off its mounting bracket on the ceiling and disconnect the power cable plugged to the smoke detector. Take out its battery, then press the “Test” button holding it down for 15 seconds. An alarm will sound for a short time, then the alarm will silence.