How do I configure the N16 SLC loop for Class A vs. Class B wiring, and what is the maximum loop impedance allowed?

Notifier INSPIRE N16Mar 19, 2026

To configure the N16 SLC loop, you must program the NFPA class configuration into the panel software; the system will automatically check for a mismatch between the programming and physical wiring (Page 17) [1].

Wiring Configurations:

Class B: Use the B+ and B- terminals on the SLM-318. T-tapping is permitted for this configuration (Page 30) [1].
Class A or X: Connect the outgoing loop to B+ and B- and the return loop to A+ and A-. T-tapping is not allowed (Page 30) [1].

Maximum Loop Impedance:

Standard SLC: 50 ohms maximum per length for Class A/X or per branch for Class B (Page 87) [1], [5].
Self-Test Detectors (CLP-2PCB): 35 ohms maximum (Page 19) [1].
Self-Test Detectors (Original CLP-PCB): 23 ohms maximum (Page 19) [1].

Additionally, the total capacitance of all SLC wiring must not exceed 0.5 microfarads (Page 20) [1].

1notifierN16Installation2022p. 28, 7, 87, 5, 30, 35Open 2notifierSLM-318Datasheet2021Open

AI-generated — verify against your panel's documentation and applicable codes (NFPA 72, local AHJ).

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