Eaton 3MM312R12RL Residential Meter Stack - UL Listed
Part Number: 3MM312R12RL
Quick Summary
Eaton residential meter stack is a three-phase in, single-phase out metering module for efficient group metering. In dense housing or small commercial projects, wiring complexity and on-site errors slow progress and drive up installation costs. UL Listed certification and TNMP utility approvals provide regulatory alignment, while the indoors/outdoors-ready enclosure supports flexible installation across varied environments. With a 125 A amperage rating and 120/208 V operation, it accommodates common residential or light commercial loads. The 1200 A bus rating with aluminum bus and five-jaw design simplifies conductor routing and enables quicker terminations. This solution supports scalable metering strategies, reduces field rework, and delivers reliable performance that improves service continuity and asset utilization.
Product Information
Extended Description
3MM312R12RL Eaton: Eaton's Three-Phase Residential Meter Stack Module, Group Metering Type, 125A, Aluminum Bus 1200 Ampere, No bypass, Indoor/outdoor, Five-jaws, 3 Sockets , Three-phase in, single-phase out, Ringless Security, 120/208V
Product Name
Eaton residential meter stack
Catalog Number
3MM312R12RL
UPC
782114786222
Product Length/Depth
40 in
Product Height
8.5 in
Product Width
15.5 in
Product Weight
57 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
Type
Residential meter stack
Utility approvals
TX : Texas-New Mexico Power (TNMP) NM : Texas-New Mexico Power (TNMP)
Interrupt rating
Depends on selected main circuit breaker
Enclosure
Indoor/outdoor
Secondary circuit breaker
BR2_, BRH2_, BRHH2_
Bus Rating
1200 A
Phase
Three-phase in, single-phase out
Voltage rating
120/208V
Amperage Rating
125A
Bus material
Aluminum
Bypass
None
Number of jaws
Five-jaw
Number of sockets
3
Phase balance
A-B
Security
Ringless
Residential and Light Commercial, Metering Products, Volume 1 Tab 4
Eaton Specification Sheet - 3MM312R12RL
Selling Policy 25-000 - Distribution and Control Products and Services
Feature → Business Impact → Application: The meter stack offers three-phase in, single-phase out configuration, which simplifies metering architecture for group metering and reduces panel clutter in multi-tenant developments. This translates to faster installation, fewer wiring errors, and improved project timelines in both multifamily and light commercial scenarios. Feature → Business Impact → Application: A 1200 A bus rating with aluminum bus and five-jaw connectors supports higher-load sections and future load growth while reducing copper costs and termination time, especially in retrofit projects and new builds with evolving electrical demands. Feature → Business Impact → Application: Indoor/outdoor enclosure provides installation flexibility across varied environments, enabling location-agnostic placement from shared electrical rooms to exterior vestibules, with consistent protection and reduced enclosure swaps. Feature → Business Impact → Application: Ringless security and no bypass design enhance safety and reliability on site, lowering maintenance visits and safeguarding metering integrity in busy installations. Feature → Business Impact → Application: Compatibility with BR2_, BRH2_, BRHH2_ secondary breakers simplifies selection and stock planning, while TNMP approvals and UL Listed certification streamline utility acceptance and compliance in regulated markets. Feature → Business Impact → Application: Clear utility approvals and a customer-centric warranty reduce risk, shorten procurement cycles, and support long-term asset management and ROI in group metering programs.
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FAQs
The 3MM312R12RL is designed to work with BR2, BRH2, and BRHH2 secondary breakers, enabling straightforward pairing for multi-residential and mixed-use installations. The five‑jaw, 3‑socket configuration and 1200 A bus support clean terminations, while the 125 A main rating aligns with common utility service requirements. This compatibility reduces the need for custom inventory and minimizes on-site adaptation, helping contractors meet tight project schedules.
Key specs include 125 A amperage rating, 120/208 V voltage rating, 1200 A bus rating, aluminum bus material, five-jaw design, and three sockets. The unit supports three-phase in and single-phase out operation, with bypass listed as none and ringless security for enhanced safety. These characteristics suit group metering for residential and light commercial deployments while delivering reliable fault tolerance and capacity for growth.
Yes. The Eaton 3MM312R12RL is specifically engineered for group metering in multi-tenant residential settings and small commercial facilities. Its indoor/outdoor enclosure and robust 1200 A bus are well-suited for shared electrical spaces or exterior installations. With 120/208 V system compatibility and a modular design, it supports scalable metering strategies, simplifies wiring, and accelerates project timelines in both new builds and renovations.
The product is UL Listed, providing a recognized safety certification for electrical equipment. It also carries TNMP utility approvals for Texas-based metering applications, facilitating utility acceptance and connection. These certifications and approvals help ensure regulatory compliance, reduce risk during inspections, and streamline project sign-off in regulated markets.
The product carries Eaton’s warranty policy (25-000), offering one year from installation or eighteen months from shipment, whichever occurs first. This warranty, combined with UL Listed certification and TNMP approvals, supports lower maintenance costs, faster service restoration in outage events, and a favorable total cost of ownership for group metering programs in both new builds and modernization projects.