How Many Smoke Alarms Can Be Interconnected?

Interconnected units must meet ALL of the following requirements:

  • 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). This type of wire is commonly available at Hardware and Electrical Supply stores.
  • All wiring must conform to all local electrical codes and NFPA 70 (NEC). Refer to NFPA 72, NFPA 101, and/or your local building code for further connection requirements.

If you are in doubt about any of these requirements, contact an experienced Electrical Professional to complete the installation of these alarms.
The maximum number of smoke alarms that should be interconnected per NFPA 72 standards is 12. Always make sure the smoke alarms you are interconnecting are compatible. In addition to the 12 smoke alarms in the series, you can connect up to 6 compatible devices like door closers, bells, or lights.