Allen-Bradley 855T-B20DN7 Stack Light Assembly

Allen-Bradley 855T-B20DN7 Stack Light Assembly is a 70 mm diameter Control Tower signaling unit with a black housing, designed for visible status indication on industrial equipment. As part of the 855T Stack Light family, this clear stack light is intended to be mounted on standard 70 mm bases and used on control panels and machinery to convey machine state at a glance. The B20DN7 configuration identifies a specific module variant within the 70 mm lineup, compatible with Allen-Bradley signaling bases and the broader Control Tower ecosystem used in Rockwell Automation environments. The 855T line supports multi-layer signaling, enabling successive lights to represent different conditions such as running, standby, warnings, or faults; the assembly can accommodate multiple colored lamps in stacked segments, with color options typically including red, green, amber, blue, and clear, depending on the installed modules. This stack light assembly is designed for industrial environments, offering straightforward inline wiring and mounting options to integrate with automation controllers or safety circuits. When selecting a model, engineers consider the mounting base compatibility (for example, 70 mm Control Tower bases) and the desired signaling configuration to achieve at-a-glance status indication across production lines or packaging equipment.