Installation, Wiring, and Testing
Scope
This domain tests how fire alarm circuits are installed, protected, supervised, and tested. Expect NEC Article 760 cable questions, Class A/B wiring, end-of-line supervision, acceptance testing, and documentation of test results.
Core rules
- Fire alarm circuits are power-limited or non-power-limited. Cable markings include FPLR for riser, FPLP for plenum, and FPL for general use; the marking must match the environment and the circuit class.
- Conductors must be supported, protected from physical damage, and separated from power circuits as required. Fire alarm cable cannot be installed in a way that compromises supervision or survivability.
- Class B circuits use an end-of-line device at the last appliance; an open circuit is detected as a trouble, but devices beyond the open may not operate. Class A returns the circuit to the panel and preserves operation beyond a single open.
- Acceptance testing verifies every initiating device, notification appliance, supervisory input, and sequence. New-system testing is not a sampling exercise.
- Records must show device identification, test results, deficiencies, and corrections. Periodic inspection and testing follow the adopted NFPA 72 edition and the AHJ’s requirements.
Worked example
A Class B notification circuit has devices 1 through 8, with the end-of-line resistor after device 8. An open occurs between devices 3 and 4. The panel sees the open and reports a trouble, but devices 4 through 8 lose supervision and may not operate on alarm. The correct diagnosis is a wiring fault in the Class B leg, not a failed appliance at device 8. If the circuit were Class A, the return conductor would let the panel continue to operate devices beyond the open, though the fault would still be annunciated. The test should verify both the trouble and the intended operation of the remaining appliances.
Traps that cost marks
- Using the wrong cable marking for a plenum or riser location.
- Leaving the end-of-line device at the panel instead of the end of a Class B circuit.
- Assuming a Class B trouble means all devices still operate.
- Sampling devices during new-system acceptance instead of testing all.
- Failing to record deficiencies and corrections.
- Ignoring separation and support requirements for fire alarm wiring.