Orbit Industries 4SB-50/75-FB 4in Square Box Fb Bracket

Product Description

The ORBIT INDUSTRIES 4SB-50/75-FB is a 4 inch square (4S) welded steel electrical box designed for standard rough-in wiring installations. The box measures 4 inches square with a 1.5 inch depth and ships with a flat bracket (FB) already welded in place, eliminating a separate fastening step on the job. Pre-punched knockouts accept both 1/2 inch and 3/4 inch conduit fittings, making it compatible with the most common EMT and rigid conduit sizes used in commercial and residential electrical work. Licensed electricians install this box during rough-in to house device, outlet, or junction wiring in conduit-fed systems.

This box is suited for commercial and residential new-construction framing applications where a 4 inch square box is specified. The welded FB bracket mounts directly to framing members or structural supports, keeping the box plumb and secure before drywall. The dual knockout sizing — 1/2 inch and 3/4 inch — supports flexible conduit routing without requiring a knockout punch on site. It is commonly used by electrical contractors running EMT through commercial tenant improvements, light industrial builds, and multi-family residential projects.

Key Features

• 4 inch square (4S) box profile — standard size for commercial device and junction applications
• 1.5 inch depth provides adequate wiring space for most device or junction configurations
• Welded FB (flat bracket) eliminates separate bracket installation during rough-in
• Pre-punched 1/2 inch and 3/4 inch knockouts accommodate the two most common EMT conduit sizes
• Welded steel construction for rigid, stable mounting in framed assemblies

Compatibility

Designed as an OEM-style replacement and standard-fit option for 4 inch square electrical box applications requiring a welded flat bracket and dual knockout sizing in 1/2 inch and 3/4 inch conduit entries.

Installation Notes

Installation should be performed by a licensed electrician in accordance with applicable NEC requirements. De-energize all circuits in the work area before making any wiring connections. Secure the welded FB bracket to the framing member so the box face sits flush with the finished wall or ceiling surface. Use listed conduit fittings sized to match the knockout openings — do not over-ream or force-fit fittings into knockouts.

Technical Specifications

• Box Shape: 4 inch Square (4S)
• Depth: 1.5 inches
• Knockout Sizes: 1/2 inch and 3/4 inch
• Bracket Type: FB (Flat Bracket), welded
• Construction: Welded steel

Standard Information

• Brand: ORBIT INDUSTRIES
• Manufacturer Part Number: 4SB-50/75-FB