Don’t Daisy-Chain Smoke Alarms: NFPA 72 Chapter 29 Compliance (Texas) - Avenger Security

Don’t Daisy-Chain Smoke Alarms: NFPA 72 Chapter 29 Compliance (Texas)

Stop wiring smoke alarms in series. In custom homes, daisy-chaining 2-wire conventional smoke alarms is a common mistake that does not meet NFPA 72 Chapter 29 and can leave the home unprotected if a single device is removed or fails.

Why Series “Daisy-Chain” Wiring Is a Code Problem

  • Single-point failure: Removing or servicing one alarm can drop power to the rest.
  • Fault intolerance: An open, short, or ground can silence multiple stations.
  • Inspection risk: This is a frequent violation called out by AHJs in new custom homes.

NFPA 72 Chapter 29—Key Clauses (Plain English)

  • 29.11.2.2: A single fault on the interconnect must not prevent any single station from operating locally.
  • 29.10.7.8.1: An open, ground fault, or short in the wiring to input/output devices must not stop each individual alarm from operating.

What Compliant Wiring Looks Like

  • Parallel power to each smoke alarm (each device is a “station”)—do not rely on series loops that drop others when one is removed.
  • Interconnection so activation of one station sounds all (where required).
  • Supervision and end-of-line (EOL) components per the manufacturer’s instructions, especially for larger networks.
  • Dedicated branch circuit for AC alarms with battery backup; follow listing/installation instructions.

What To Do If You Find Daisy-Chain Wiring

  1. Document the condition (photos/video) and note which devices go down when one is removed.
  2. Rewire to parallel power with proper interconnect and supervision per the alarm manufacturer.
  3. Function-test all stations and the interconnect; verify local sounder at each device.
  4. Coordinate with your AHJ and update as-builts for inspection.

Field Example (Video)

Common violation: series-wired smoke alarms that drop the entire chain when one is removed.

Need Help?

We correct non-compliant wiring and integrate alarms properly with monitored systems. Learn more about our Fire & Life Safety services or request a site visit.

Informational only. Always consult the current NFPA 72 edition and your local Authority Having Jurisdiction (AHJ).

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