Eaton 3MTB1200R Main Terminal Box - UL Listed
Part Number: 3MTB1200R
Quick Summary
Eaton 3MTB1200R main terminal box distributes 120/208 V three-phase power for industrial electrical rooms. Engineers often struggle with lug landing compatibility, enclosure footprint, and installation time on upgrades. This UL Listed solution is housed in a durable NEMA 3R enclosure to withstand indoor and outdoor conditions, delivering robust protection against water and dust. The unit is rated for 1200 A, uses aluminum bus, and supports top/bottom feed with four conductors using four 250–500 kcmil cables. By consolidating main-termination tasks, it reduces field labor, accelerates commissioning, and simplifies compliance for utilities and contractors. For larger conductor runs, compression lug landing kits such as 3MTB1200CLK extend compatibility without rework.
Product Information
Extended Description
3MTB1200R Eaton: Eaton main terminal box, 1200A, Aluminum, NEMA 3R, Overhead/underground, Four-wire, Three-phase, 120/208V, (4) 250-500 kcmil
Product Name
Eaton main terminal box
Catalog Number
3MTB1200R
UPC
782116007899
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 and 1200A units, for compression lug landing kits, order 3MTB1200CLK. Kits includes lug landing for three-phase and neutral.
Amperage Rating
1200A
Bus material
Aluminum
Feed type
Top/bottom
Phase
Three-phase
Voltage rating
120/208 V
Wire size
(4) 250-500 kcmil
Utility approvals
MI : Consumers Energy NC : Dominion VA : Dominion MI : DTE Energy (Detroit Edison) CA : Sacramento Municipal Utility District (SMUD) 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 - 3MTB1200R
The 3MTB1200R delivers a 1200A amperage rating with an aluminum bus and top/bottom feed, supporting four-wire configurations for large feeders. This combination minimizes voltage drop and simplifies the main termination, reducing installation time and space in the switchgear footprint. Applications include heavy manufacturing lines and large commercial facilities requiring robust three-phase distribution for 120/208 V systems. NEMA 3R enclosure provides weather-resistant protection for indoor or outdoor installations, safeguarding terminations against dust, moisture, and incidental impacts. The rugged design supports overhead and underground service environments, keeping critical power fed to downstream equipment without frequent rework. Lug landing compatibility is enhanced with ready-to-use lug options and the optional compression lug landing kit (3MTB1200CLK) for larger conductor runs; this reduces field labor and potential mis-wiring during conversion or upgrades. The top/bottom feed arrangement also offers routing flexibility, simplifying panel layout and service entrance design. UL Listed certification ensures conformity to safety standards, expediting procurement in regulated facilities and helping meet commissioning timelines. The combination of UL safety qualification and NEMA protection aligns with utility and contractor expectations for reliability in mission-critical environments. Supplier documentation and warranty support add business value; Eaton backs the product with a clear warranty and comprehensive spec sheets to support planning and maintenance.
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FAQs
For 800A and 1200A units, use the compression lug landing kit 3MTB1200CLK. This kit includes lug landing provisions for three-phase and neutral, simplifying field modifications and ensuring a clean, code-compliant termination path without rework or extensive labor.
The 3MTB1200R is rated for 1200 A with aluminum bus, supports top/bottom feed, and a four-wire configuration for three-phase 120/208 V systems. It accommodates (4) 250–500 kcmil conductors, providing large-conductor capacity for demanding feeder applications.
Yes. The enclosure is NEMA 3R rated, offering weather-resistant protection suitable for both indoor and outdoor installations, including overhead and underground service environments. This enables reliable main-termination that can endure challenging site conditions without additional shielding.
The product is UL Listed, ensuring compliance with safety standards for electrical equipment. It features a NEMA 3R enclosure rating for rugged protection, supporting safe operation in varied environments. These certifications help streamline procurement and commissioning for regulated facilities.
Eaton provides a warranty policy of one year from installation or eighteen months from shipment, whichever occurs first. In addition, comprehensive datasheets and catalogs are available to support proper sizing, installation planning, and ongoing maintenance, contributing to lower total cost of ownership.