Within 24 inches of building entry, alarm circuits terminate to which device?

• A. 66 Block or other terminal demarc block
• B. Patch Panel
• C. Terminal Strip
• D. Distribution Box

Answer: (A)

Alarm circuits have a defined boundary point right where they enter the building. This boundary point is the termination location that separates the service provider’s wiring from the customer’s internal wiring, making testing and troubleshooting straightforward. A 66 block, or another terminal demarc block, is used here because it provides a centralized, accessible termination that’s easy to test and label. It’s the standard point for the alarm circuits to land within 24 inches of the entry, ensuring a clear demarc and convenient maintenance. Patch panels, terminal strips, and distribution boxes serve other functions or contexts and aren’t the designated demarc point at the building entry for alarm circuits.