Middle Atlantic CI DP FLR BX SGL SRV - 889B

Middle Atlantic 889B Cast Iron Concrete Floor Box

Overview

The Middle Atlantic 889B is a single-service cast iron floor box designed for concrete floor installations — the type of infrastructure detail that separates a clean AV or security integration from one riddled with trip hazards and surface conduit. At 4.8 in × 4.8 in footprint and 3.5 in depth, the 889B fits into standard concrete rough-in cutouts while keeping the profile low enough to avoid furniture clearance conflicts. TAA compliance means this unit qualifies for federal, state, and municipal procurement programs without sourcing headaches. Explore the full Middle Atlantic infrastructure catalog for compatible raceways, enclosures, and power distribution.

Key Features

• Compact 4.8 × 4.8 in Square Footprint: The uniform square profile simplifies rough-in layout — both dimensions are identical, so orientation doesn't matter during pour planning. Fewer measurement errors on the jobsite.
• 3.5 in Depth: Shallow enough to accommodate standard concrete slab pours without requiring a recessed form block, while still providing adequate wire management depth for a single service run. Check your slab spec before ordering deeper alternatives.
• Cast Iron Construction: Cast iron handles the compressive load of foot traffic and rolling carts without deforming — a meaningful difference over thermoplastic floor boxes in warehouse corridors, lobbies, and commercial office floors where wheeled equipment is common.
• Single-Service Configuration: The 889B is sized for one service pass-through. That's intentional — multi-service applications should use a larger box. Trying to force two conduit runs into a single-service box creates a pull nightmare at rough-in.
• TAA Compliant: Verified TAA compliance means the 889B is eligible for GSA Schedule purchases and government-funded projects subject to the Trade Agreements Act. No additional documentation chase required — compliance is built in.

Integration & Compatibility

The 889B is designed to integrate with standard concrete floor box ecosystems. Pair with Middle Atlantic or compatible cover plates and service inserts to complete the assembly. For AV and security infrastructure deployments, coordinate with your conduit sizing before pour — single-service boxes limit future re-pull flexibility, so plan cabling routes carefully at design stage. Consider structured cable management accessories when routing from floor box to wall or ceiling distribution points. For projects requiring multiple service ports at a single floor location, evaluate a larger-capacity floor box in the Middle Atlantic line before specifying the 889B.

Frequently Asked Questions

Q: Is the Middle Atlantic 889B TAA compliant?

A: Yes. The 889B carries verified TAA (Trade Agreements Act) compliance, making it eligible for federal, state, and government-funded procurement programs subject to TAA requirements.

Q: What are the dimensions of the 889B?

A: The 889B measures 4.8 in × 4.8 in (12.2 cm × 12.2 cm) in width and depth, with a height of 3.5 in (8.9 cm).

Q: How many service ports does the 889B support?

A: The 889B is a single-service floor box. It is designed for one conduit or service pass-through. Multi-service applications require a larger box model.

Q: Is the 889B suitable for concrete floor installations?

A: Yes. The 889B is a cast iron concrete floor box, purpose-built for in-slab installation in concrete floor pours in commercial and institutional environments.

Q: Can the 889B handle rolling cart or foot traffic loads?

A: Cast iron construction provides the compressive strength to withstand standard commercial foot traffic and wheeled equipment loads — a meaningful advantage over plastic floor boxes in active-use areas.

James Everett

The Middle Atlantic 889B comes up regularly in government and institutional bids specifically because of its TAA compliance status — when procurement requires it, you don't have to hunt for a compliant substitute. The 4.8 × 4.8 in footprint and 3.5 in depth are well-matched to standard concrete rough-in practice, and the cast iron body holds up in corridors and lobbies where a plastic box would eventually crack under load.

Technical Highlights:

• TAA Compliance: Verified compliant — qualifies for GSA Schedule and government-funded deployments without additional sourcing documentation.
• 4.8 × 4.8 × 3.5 in Envelope: Symmetric footprint simplifies layout during form-board placement; 3.5 in depth fits standard slab pours without special formwork.
• Cast Iron Body: Handles compressive loads from foot traffic and wheeled carts — appropriate for high-traffic commercial floors where thermoplastic boxes fail over time.

Deployment Considerations:

• The 889B is a single-service box — plan conduit routing before the pour. Retrofitting a second service into a single-service box after concrete is set is expensive and often not feasible.
• Verify cover plate and service insert compatibility with your finishing contractor before ordering — the box rough-in is only half the assembly.

The 889B is the right spec for TAA-required government office, federal facility, or institutional campus deployments where a single low-profile concrete floor service point is needed and compliance documentation must be clean from day one.