Eaton 3MM320R Meter Stack - UL Listed Group Metering
Part Number: 3MM320R
Quick Summary
Eaton residential meter stack enables compact three-phase metering for multi-tenant facilities. Managing multiple feeders and meter configurations can be error-prone and costly without a scalable solution. Key certifications and compliance include UL Listed safety certification, outdoor-rated enclosure suitability, and broad utility approvals across major service territories. This meter stack enables faster installation, safer operation, and reliable group metering across 120/208V systems, delivering business value through reduced labor, improved data accuracy, and long-term cost savings. Designed for durable outdoor use, the rugged aluminum bus and five-jaw design support easy maintenance and long service life. By consolidating metering hardware, it also simplifies compliance documentation and utility interconnection processes.
Product Information
Extended Description
3MM320R Eaton: Eaton's Three-Phase Residential Meter Stack Module, Group Metering Type, 200A, Aluminum Bus 800 Ampere, No bypass, Outdoor, Five-jaws, 3 Sockets, Three-phase in, single-phase out, Ring Security 120/208V
Product Name
Eaton residential meter stack
Catalog Number
3MM320R
UPC
786849052027
Product Length/Depth
54.5 in
Product Height
8 in
Product Width
16 in
Product Weight
65 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
Group Metering
Utility approvals
MD : First Energy (Potomac Edison) AL : Alabama Power DC : Atlantic City Electric / Delmarva (Connectiv) DE : Atlantic City Electric / Delmarva (Connectiv) MD : Atlantic City Electric / Delmarva (Connectiv) NJ : Atlantic City Electric / Delmarva (Connectiv) TX : CenterPoint Energy (HL&P/Reliant) NC : Dominion VA : Dominion MI : DTE Energy (Detroit Edison) NM : El Paso Electric TX : El Paso Electric MO : Empire District Electric OK : Empire District Electric AR : Entergy LA : Entergy MS : Entergy TX : Entergy CA : City of Los Angeles - DWP (LADWP) AZ : Southern California Edison CA : Southern California Edison CA : Pacific Gas and Electric (PG&E) CA : Sacramento Municipal Utility District (SMUD) TN : Nashville Electric Service CA : PacifiCorp/Pacific Power/Rocky Mountain Power ID : PacifiCorp/Pacific Power/Rocky Mountain Power OR : PacifiCorp/Pacific Power/Rocky Mountain Power UT : PacifiCorp/Pacific Power/Rocky Mountain Power WA : PacifiCorp/Pacific Power/Rocky Mountain Power WY : PacifiCorp/Pacific Power/Rocky Mountain Power HI : Hawaiian Electric MT : NorthWestern Energy NE : NorthWestern Energy SD : NorthWestern Energy WY : NorthWestern Energy MD : Baltimore Gas and Electric DC : PEPCO MD : PEPCO AZ : Tucson Electric Power/ UniSource AZ : Sulphur Springs Valley Electric Coop IN : Indianapolis Power and Light (IP&L)
Interrupt rating
Depends on selected main circuit breaker
Enclosure
Outdoor
Secondary circuit breaker
CCV2_X, CCVH2_X, CVS2_XMM, CV2_XMM, CVH2_XMM
Bus Rating
800 A
Phase
Three-phase in, single-phase out
Voltage rating
120/208V
Amperage Rating
200A
Bus material
Aluminum
Bypass
None
Number of jaws
Five-jaw
Number of sockets
3
Phase balance
A-B
Security
Ring
Residential and Light Commercial, Metering Products, Volume 1 Tab 4
Eaton Specification Sheet - 3MM320R
Feature: Group Metering design with three-phase in, single-phase out and five-jaw, three-socket layout. Business Impact: Simplifies feeder connections and reduces wiring complexity, enabling faster field assembly and safer fault isolation. Application: Ideal for group metering in multi-tenant residential buildings and small commercial campuses. Feature: Outdoor enclosure for weather resistance. Business Impact: Enables outdoor installation with reliable protection against environmental exposure, reducing indoor space needs. Application: Outdoor meter stacks in exterior corridors or mechanical rooms. Feature: Aluminum bus rated 800 A. Business Impact: Provides high current handling with lighter weight and corrosion resistance, improving installation practicality and long-term reliability. Application: Residential meter stacks supporting 200 A service with durable bus construction. Feature: Interrupt rating depends on selected main circuit breaker. Business Impact: Offers design flexibility to balance protection level and cost, aligning with site-specific codes and utility requirements. Application: Customizable protection for multi-tenant service feeders. Feature: Broad utility approvals. Business Impact: Reduces field interconnection delays by supporting numerous utility service territories. Application: Installed in facilities serving multiple state and utility entities. Feature: UL Listed certification. Business Impact: Ensures safety compliance and market acceptance across regions. Application: Essential for code-conscious installations and inspector-ready deployments.
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FAQs
The 3MM320R is designed for outdoor installation with an outdoor enclosure. For proper mounting, ensure a sturdy wall or pedestal, allow clear access to the five-jaw enclosure, and verify clearance for service connections. Catalog and UPC information should be referenced during initial wiring and field labeling, and ensure weather seals are intact to maintain UL Listed compliance.
Interrupt rating for the 3MM320R depends on the main circuit breaker you select. This provides design flexibility to balance protection level and cost. When selecting breakers, verify compatibility with the 800 A bus rating and ensure the combination meets local utility and code requirements for three-phase in, single-phase out metering.
Yes. The 3MM320R carries UL Listed certification and is backed by broad utility approvals across many states and utilities, as listed in Eaton’s specifications. This reduces field approval times and supports interconnection with a wide range of service territories, simplifying project timelines for multi-tenant properties.
Its outdoor enclosure, aluminum bus, five-jaw design, and three sockets support robust routing of three-phase in and single-phase out distributions. The rugged build, UL safety certification, and utility compatibility translate to safer installations, improved data accuracy, and scalable metering for multi-tenant facilities without excessive indoor footprint.
Eaton provides a warranty per policy 25-000: one year from installation or eighteen months from shipment, whichever occurs first. Regular maintenance includes inspection of connections, enclosure seals, and bus terminations. Adhering to installation guidelines and using approved main breakers helps preserve performance and reliability over the product’s life cycle.