NFPA 99 allows how many sets of wires to connect the initiating device with the junction box for each signal?

NFPA 99 allows how many sets of wires to connect the initiating device with the junction box for each signal?

• A. Two
• B. Three
• C. Four
• D. One

Answer: (D)

The key idea is that initiating devices in life-safety wiring should have a single, dedicated path for each signal. NFPA 99 requires only one set of conductors connecting the initiating device to the junction box for a given signal. This ensures the signal path is unambiguous, easy to test, and not opened up to cross-connection or backfeeding between different circuits or functions. In practice, you run just one two-conductor cable from the device to the junction box (and onward to the control equipment), keeping the signal path clean and traceable. If a device has multiple signaling functions, each function would use its own set of conductors, but for any single signal there is only one set.

The key idea is that initiating devices in life-safety wiring should have a single, dedicated path for each signal. NFPA 99 requires only one set of conductors connecting the initiating device to the junction box for a given signal. This ensures the signal path is unambiguous, easy to test, and not opened up to cross-connection or backfeeding between different circuits or functions.

In practice, you run just one two-conductor cable from the device to the junction box (and onward to the control equipment), keeping the signal path clean and traceable. If a device has multiple signaling functions, each function would use its own set of conductors, but for any single signal there is only one set.