STI STI-1221D Strobe Damage Stopper Back Box with Conduit Knockout
Overview
The STI-1221D is a protective back box and mounting frame designed to shield strobe notification appliances from impact and environmental exposure. The unit combines a damage-resistant enclosure with an open back design and 3/4 in. rigid conduit knockout, enabling flexible wiring entry for door strikes, access control panels, and life safety alarm circuits. Frame dimensions are 6.5 in. wide × 8.5 in. high × 3.5 in. deep, providing enough internal space for standard notification device mounting while protecting vulnerable components from accidental or deliberate damage in high-traffic areas.
Compatibility
The STI-1221D is designed for integration with typical fire alarm, access control, and door strike installations in commercial and institutional buildings. The open back configuration and conduit knockout accept standard 3/4 in. rigid conduit, making it compatible with existing NEC and NFPA-code-compliant notification system layouts. Use with strobe assemblies, sounder-strobe combinations, and associated signaling devices specified under STI environmental notification appliance standards. The frame assembly includes standoff blocks and mounting clamps to secure devices within the enclosure while maintaining airflow and visibility of strobe output.
Installation Notes
Mount using (4) provided Rawl plugs and #10 × 1½ in. head cap screws into masonry or concrete; install the mounting clamp in the notch as shown in the exploded view. The back of the frame may be drilled to allow additional wire routing if environmental conditions or code inspection require added protection. Insert the cover frame assembly tabs into the mounting slots; secure with (4) #8-32 × 3/8 in. socket head cap screws. If frequent wash-downs or high-moisture conditions are expected, order the optional SUB-122 environmental kit with additional sealing. Refer to the detailed assembly diagram and local electrical code requirements before final commissioning.
What's in the Box
- 1× Frame Assembly (06297B)
- 1× Cover Only (01221)
- 2× Standoff Blocks
- 1× Mounting Clamp
- 4× Rawl Plugs
- 4× #8-32 × 3/8 in. Socket Head Cap Screws
- 4× #10 × 1½ in. Head Cap Screws
