Eaton 3MTB800R Main Terminal Box - UL Listed
Part Number: 3MTB800R
Quick Summary
Eaton 3MTB800R main terminal box provides robust 800A distribution for three-phase, 120/208 V systems in industrial facilities. Site crews often struggle with outdoor-rated equipment that resists weather, corrosion, and heavy feeders; this box addresses those pain points. UL Listed protection and a NEMA 3R enclosure support reliable operation in variable conditions, while aluminum bus enables efficient current flow. Designed for compatibility with heavy feeders and flexible wiring, it helps reduce installation time and total cost of ownership for harsh environments and high-demand applications.
Product Information
Extended Description
3MTB800R Eaton: Eaton Main Terminal Box, 800A, Aluminum, NEMA 3R, Overhead/underground, Four-wire, Three-phase, 120/208V, (2) 250-500 kcmil
Product Name
Eaton main terminal box
Catalog Number
3MTB800R
UPC
786849053109
Product Length/Depth
11.19 in
Product Height
47.7 in
Product Width
20.17 in
Product Weight
85 lb
Warranty
Eaton Selling Policy 25-000, one (1) year from the date of installation of the Product or eighteen (18) months from the date of shipment of the Product, whichever occurs first.
Certifications
UL Listed
Catalog Notes
For 800A units, to obtain (4) 1/0-300 kcmil or (2) 1/0-750 kcmil cables per phase- order catalog number 3MTB800BLK, one Lug Kit per main terminal box ordered (neutral and ground included in kit). For 800A and 1200A units, order 3MTB1200CLK.
Amperage Rating
800A
Bus material
Aluminum
Feed type
Top/bottom
Phase
Three-phase
Voltage rating
120/208 V
Wire size
(2) 250-500 kcmil
Utility approvals
MI : Consumers Energy NC : Dominion VA : Dominion MI : DTE Energy (Detroit Edison) MT : NorthWestern Energy NE : NorthWestern Energy SD : NorthWestern Energy WY : NorthWestern Energy MD : Baltimore Gas and Electric DC : PEPCO MD : PEPCO
Enclosure
NEMA 3R
Number of wires
4
Residential and Light Commercial, Metering Products, Volume 1 Tab 4
Eaton Specification Sheet - 3MTB800R
Feature: 800A amperage rating with aluminum bus. Business Impact: Minimizes voltage drop and supports high-load distribution with durable, low-resistance wiring paths. Application: Ideal for central feeder boxes in industrial plants and large commercial facilities. Feature: NEMA 3R enclosure with weather resistance. Business Impact: Enables outdoor/overhead or underground installations with reliable protection against the elements. Application: Outdoor electrical rooms, exterior switchgear, and rooftop distribution. Feature: Top/bottom feed and four-wire, three-phase configuration. Business Impact: Flexible installation options reduce wiring complexity and retrofit downtime. Application: Main distribution points where space and routing vary between facilities. Feature: Large conductor capacity (2) 250-500 kcmil per phase. Business Impact: Supports scalable upgrades and minimizes lug replacements during expansion. Application: Primary feeders feeding multiple subcircuits. Feature: UL Listed with utility-friendly compatibility. Business Impact: Ensures compliance and smoother procurement across facilities. Application: Projects requiring proven reliability and regulator-ready components. Feature: Catalog notes for lug kits and special configurations (e.g., 3MTB800BLK, 3MTB1200CLK). Business Impact: Streamlines sourcing and enables customized terminations without redesign. Application: Prepares for long-term upgrades and specific cable sets in high-capacity systems.
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FAQs
The 3MTB800R supports two conductors per phase of heavy-gauge cables: (2) 250-500 kcmil per phase in a four-wire, three-phase configuration. For specific configurations, refer to Eaton catalog notes: for 800A units you can order (4) 1/0-300 kcmil or (2) 1/0-750 kcmil cables per phase with the appropriate lug kit.
Yes. The enclosure is NEMA 3R rated and UL Listed, providing weather resistance for overhead/underground use. The aluminum bus and robust construction support outdoor distribution, reducing the need for additional enclosures in many outdoor applications.
Key specs include an 800A amperage rating, aluminum bus material, three-phase configuration, and a 120/208 V voltage rating with top/bottom feed. The unit supports four wires and is UL Listed with a NEMA 3R enclosure, suitable for heavy-duty distribution in industrial environments.
The product carries Eaton’s warranty policy: one year from installation or eighteen months from shipment, whichever occurs first. For service, field support, and updates, refer to Eaton Selling Policy 25-000 for precise terms and conditions.
Plan for top/bottom feed with (2) 250-500 kcmil conductors per phase and ensure space for a four-wire, three-phase configuration. If upgrading cable kits later, consider the lug kit options (e.g., 3MTB800BLK) and higher-capacity configurations (3MTB1200CLK) for 800A and 1200A systems to simplify sourcing and termination.