Orbit FA-4S Deep 4" Square Welded Fire Alarm Box with MKO

Orbit FA-4S Deep 4" Square Welded Fire Alarm Box with MKO

The Orbit FA-4S is a deep, 4" square fire alarm box built with fully welded construction and a machine-knockout (MKO) design, engineered to provide a rugged, secure enclosure for fire alarm system components in commercial and industrial electrical installations. This family is available in two deep-body depth options, 2-1/8" and 3-1/2", giving installers a choice of interior volume within the same compact 4" square footprint depending on the wiring, splice, and device-mounting room required for the job. Welded seams deliver a solid, one-piece enclosure that resists flexing and separation across both depth options, while the MKO feature allows for clean, controlled conduit entry points to be made in the field as needed for the specific installation layout.

Key Features

• 4" Square Footprint: Sized to the standard 4" square format for compatibility with common fire alarm system layouts and mounting hardware.
• Deep Body Profile, 2-1/8" or 3-1/2": Choose the depth that best fits the installation, with extra interior room for wiring, device mounting, and splice management versus a standard shallow box.
• Welded Construction: Fully welded seams create a durable, one-piece enclosure that resists separation and adds structural rigidity for long-term reliability across both depth options.
• MKO (Machine Knockout) Design: Knockout points are engineered for clean conduit entry, allowing installers to open only the entries required for the job.
• Fire Alarm System Application: Purpose-built as a fire alarm box, suited for housing fire alarm devices, pull stations, or associated wiring within a code-driven electrical layout.
• Consistent Family Design: Both the 2-1/8" and 3-1/2" deep versions share the same 4" square welded body and MKO conduit-entry design, so installers can standardize on the FA-4S family and select depth per application.

Technical Specifications

• Size: 4" Square
• Depth Options: 2-1/8" and 3-1/2"
• Construction: Welded
• Knockout Type: MKO (Machine Knockout)

Typical Applications

• Fire Alarm System Installations
• Commercial and Industrial Electrical Enclosures
• Conduit and Raceway Systems
• New Construction and Retrofit Fire Alarm Wiring
• Device and Pull Station Housing

Why Orbit?

Orbit's FA-4S family delivers the welded, deep-body construction and MKO conduit entry design that installers rely on for dependable fire alarm box performance, whether the job calls for the 2-1/8" or 3-1/2" depth option. The one-piece welded body and generous interior depth across both sizes make this family a practical choice for professional electrical work where durability, flexibility in interior volume, and clean conduit routing matter.