Are class B SLCs permitted to be T-tapped?

• A. Not permitted
• B. Yes
• C. Only under special circumstances
• D. Only with manufacturer approval

Answer: (B)

The concept here is how Signaling Line Circuits are wired and how taps are treated on them. On a Class B signaling line circuit, devices are connected along a single two‑wire path between the panel and the devices. You can add more devices by tapping off the main line, creating branches, without breaking the circuit’s ability to be supervised. As long as the taps are done according to the system’s listing and installation instructions, the end-of-line resistor is placed correctly, and the overall impedance stays within what the panel and devices are designed to tolerate, the circuit remains properly monitored and functional.

So, tapping a Class B SLC is allowed under standard installation practices, which is why the correct answer is that it is permitted. Always follow the manufacturer’s guidelines and applicable codes to ensure proper supervision and performance.