STI STI-1200A Stopper II® Enclosed Back Box with Fire Label
The STI-1200A is a 4-inch-deep enclosed back box designed to mount and protect UL-listed fire alarm initiating devices (38 and 2017 standards) in outdoor and temperature-extreme environments. This unit pairs a clear polycarbonate cover with a NEMA 3R-rated steel enclosure — the combination handles rain, sleet, and external ice formation without compromising device accessibility or signal integrity.
Overview
Use the STI-1200A when your fire alarm pull station, call point, or similar initiating device must survive outdoor exposure or uncontrolled interior spaces (loading docks, unheated warehouses, exterior building facades). The 4-inch depth accommodates standard wiring and conduit connections behind the device. NEMA 3R rating means you avoid water pooling or ice damage that would otherwise degrade electrical contacts or obscure the device face. The unit is ADA compliant, positioning controls and labels at accessible heights and clearances. Clear polycarbonate construction is UV-stabilized to prevent yellowing under sunlight, preserving visibility of printed fire labels and device status indicators over years of outdoor service.
Compatibility
The STI-1200A back box is designed for STI Stopper II® Series initiating devices and other UL 38 / UL 2017-listed call points and manual pull stations. Confirm the specific initiating device height and connector type match the 4-inch back-box depth before ordering. The enclosure mounts to standard electrical boxes or direct to wall studs using provided hardware. Conduit or raceway entries must seal as close as possible to the enclosure to prevent moisture ingress — consult NEC Article 725 and 760, and NFPA 72 standards for specific pathway requirements in your jurisdiction.
Installation Notes
Installer must comply with NEC Articles 725 and 760, NFPA 72, and local fire and electrical codes. Seal conduit and raceway entries near the enclosure to minimize water entry. The unit requires 24VDC supply for optional heater modules (sold separately, such as STI-1200A-HTR or STI-1200A-HTR240) if protecting devices in sub-zero climates. If a heater is installed, it runs continuously to maintain uniform internal temperature and cycles the heating element as needed; no standby power is required. Unheated models operate to standard UL temperature limits; heated variants maintain device function to -70°F (-57°C). Lifetime warranty against breakage of polycarbonate in normal use covers the housing — electromechanical and electronic components on heated versions carry a one-year warranty.
