In a Class B initiating circuit, wires should be monitored for integrity by having a...

In aClass B circuit, supervision of wiring integrity is accomplished using anEnd-of-Line Resistor (EOLR)at thelast devicein the circuit. This allows the control unit to detect open faults.

NFPA 72 (2022), Section 12.3.4.1:

“Initiating device circuits shall be monitored for integrity by placing an end-of-line device at the last device on the circuit.”

If the wiring is cut or disconnected before the last device, the panel detects it as a trouble condition.

Correct answer: D. The last detector

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