Milbank 320A Ring-Type Meter S...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$9,321.46
Milbank 4 Terminal Ring-Type Plain Top 120/240V 320 Amperes Main Breaker

Milbank 320A Ring-Type Meter Socket with Main Breaker and Load Center - 120/240V Single Phase Underground Service

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Model: M401-UG-BS

In Stock (leaves warehouse same day if ordered before 3pm ET)

$9,321.46
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Milbank 320A Ring-Type Meter Socket with Main Breaker and Load Center

Professional electrical service entrance solution with integrated load management

The Milbank 320A Ring-Type Meter Socket delivers comprehensive electrical service entrance capabilities with integrated main breaker protection and load center functionality. This single-phase 120/240V system combines meter socket, 400A main breaker, and 12-circuit load center in a durable G90 galvanized steel enclosure with powder coat finish, designed for reliable underground service applications with Type 3R weather protection.

Professional Features & Benefits

  • 320 Continuous Ampere Rating: Provides substantial electrical capacity for residential and light commercial applications with reliable current handling.
  • 400A Main Breaker Protection: Integrated overcurrent protection safeguards downstream circuits and equipment from electrical faults and overloads.
  • 12-Circuit Load Center: Built-in distribution panel eliminates need for separate load center installation, reducing material and labor costs.
  • Type 3R Weather Rating: UL Listed enclosure provides protection against rain, sleet, and ice formation for outdoor installations.
  • G90 Galvanized Steel Construction: Corrosion-resistant material with powder coat finish ensures long-term durability in harsh environmental conditions.
  • Underground Cable Entry: Designed for underground service connections with appropriate wire range accommodation from 6 AWG to 350 kcmil.
  • Light Kit with Photocell: Integrated lighting system with automatic daylight control enhances safety and visibility during service operations.

Technical Specifications

  • Amperage Rating: 320 Continuous Ampere
  • Application: Meter Socket With Main
  • Barrel Lock Provision: 7/16 Inch Knockout for Barrel Lock Provision
  • Brand Name: Milbank
  • Cable Entry: Underground
  • Departent: Electrical
  • Equipment Ground: 2 Barrel Ground Lug
  • Frequency Rating: 60 Hertz
  • Hub Closing Plate: Plain Top
  • Insulation: Glass Polyester
  • Light Kit: Light Kit with Photocell
  • Line Side Wire Range: 6 AWG - 350 kcmil
  • Load Center: 12 Circuit Load Center
  • Load Side Wire Range: 3/0 AWG - 300 kcmil
  • Main Breaker Size: One 400 Ampere Main Breaker
  • Number Branch Circuits: 1
  • Number Of Jaws: 4 Terminal
  • Number Of Main Breakers: 1
  • Number Of Meter Positions: 1 Position
  • Phase: 1 Phase
  • Product Family Code: HPWR
  • Product Height: 38 IN
  • Product Material: G90 Galvanized Steel with Powder Coat Finish
  • Product Mounting: Surface Mount
  • Product Type: Ring Type Meter Socket
  • Receptacle Configuration: Four NEMA 5-20 Ground Fault
  • Standard: UL Listed;Type 3R
  • Terminal: 1/2 Inch Stud Line Side
  • Unspsc Number: 39121102
  • Voltage Rating: Up to 240 Volts Alternating Current
  • Width: 24.88 IN

Professional Applications

  • Residential Service Entrance Systems
  • Small Commercial Facilities
  • Multi-Unit Residential Properties
  • Professional Office Buildings
  • Retail Establishments
  • Light Industrial Applications
  • Underground Utility Service Connections

Why Choose Milbank Quality?

Milbank delivers proven reliability through UL Listed construction and Type 3R weather protection rating. The G90 galvanized steel enclosure with powder coat finish provides exceptional corrosion resistance, while the integrated design reduces installation complexity and long-term maintenance requirements for professional electrical service applications.

Manufacturer Resources

Product Specs

Amperage Rating:
320 Continuous Ampere
Application:
Meter Socket With Main
Barrel Lock Provision:
7/16 Inch Knockout for Barrel Lock Provision
Brand Name:
Milbank
Cable Entry:
Underground
Equipment Ground:
2 Barrel Ground Lug
Frequency Rating:
60 Hertz
Hub Closing Plate:
Plain Top
Insulation:
Glass Polyester
Light Kit:
Light Kit with Photocell
Line Side Wire Range:
6 AWG - 350 kcmil
Load Center:
12 Circuit Load Center
Load Side Wire Range:
3/0 AWG - 300 kcmil
Main Breaker Size:
One 400 Ampere Main Breaker
Number Branch Circuits:
1
Number Of Jaws:
4 Terminal
Number Of Main Breakers:
1
Number Of Meter Positions:
1 Position
Phase:
1 Phase
Product Family Code:
HPWR
Product Height:
38 IN
Product Type:
Meter Main Combination
Receptacle Configuration:
Four NEMA 5-20 Ground Fault
Standards:
UL Listed;Type 3R
Terminal:
1/2 Inch Stud Line Side
Unspsc Number:
39121102
Voltage Rating:
Up to 240 Volts Alternating Current
Product Material:
G90 Galvanized Steel with Powder Coat Finish
Product Mounting:
Surface Mount
Amps:
320
Product Width:
24.88 IN
Department:
Electrical
Product Subgroup:
Metering & Meter Sockets
Insulation Type:
Glass Polyester
Hub Style:
Plain Top
Installation Category:
Surface Mount
Terminal Type:
1/2 Inch Stud Line Side
Number of Phases:
1
Product Details:
Ring Type Meter Socket
Frequency:
60 hertz
Number of Terminations:
4
Product Group:
Power Distribution

Milbank M401-UG-BS – Frequently Asked Questions

1) Will a Milbank M401-UG meter socket work on 200A underground service, or do I need a full 320A service?
The Milbank M401-UG is built as a 320 continuous ampere service entrance device (400A main breaker inside), single phase, up to 240 volts AC, 60 Hz. You can install it on a smaller service, but the line side lugs take 6 AWG through 350 kcmil, so the conductors a 200A feed uses land fine. The limiting factor is the utility: the socket is a 4 terminal ring type, 1 meter position, underground cable entry. If the utility wants an overhead lever bypass socket or a different jaw count, this is the wrong can.
2) What is the difference between the Milbank M401-UG and the M401-UG-BS?
Bypass. The M401-UG has no bypass; the M401-UG-BS is the link bypass version, which lets the meter be pulled and the service kept energized through the bypass links. Everything else is the same 320A, 4 terminal ring type, underground, plain top socket with the 400A main and 12 circuit load center. Most utilities specify one or the other by name, so check the utility's approved meter equipment list before you pick.
3) Can I feed a subpanel from the Milbank M401-UG, and what size conductors will the load side lugs take?
Yes. Load side wire range on the M401-UG is 3/0 AWG through 300 kcmil, which covers the usual 320A service feeders run to an interior panel. Note the minimum: 3/0 is the smallest conductor the load lugs are rated for, so you cannot land a small feeder directly. Line side terminals are 1/2 inch studs taking 6 AWG to 350 kcmil.
4) Is the Milbank M401-UG rated for outdoor mounting on the side of a building?
Type 3R and UL Listed, so it is made for outdoor service entrance work. The enclosure is G90 galvanized steel with a powder coat finish, and the internal insulation is glass polyester. It is a plain top with underground cable entry, so there is no hub opening for a weatherhead riser.
5) Can I use a plain top underground meter socket for overhead service if I punch a hub in it?
Not as furnished. The M401-UG ships plain top for underground entry, which means no factory hub opening and no closing plate provision for a riser. For an overhead drop you need the overhead version of the socket with a hub opening, not a field modification of this can. Cutting a top entry into a Type 3R enclosure voids the UL Listing on it.
6) Will a single phase 320A meter socket work for a 3 phase commercial service?
No. The M401-UG is 1 phase, 4 terminal, up to 240 volts, 60 Hz, which is the standard 120/240V single phase residential and light commercial configuration. A three phase service needs a 7 jaw socket sized to that system. Check jaw count against what the utility specifies before ordering, because 4 terminal is the tell here.
7) How much wall space do I need for a 320A Milbank meter main combo?
Plan on 38 inches high by 24.88 inches wide for the M401-UG enclosure, surface mounted. That is the can alone, before working clearance in front of it. It is a one piece assembly, so you are not stacking a separate load center beside it.
8) How many breaker spaces does the Milbank 320A meter main have, and how many circuits can I actually run from it?
The built in distribution section is a 12 circuit load center, fed by one 400 ampere main breaker. That is the panel capacity in the can itself; anything beyond it has to come off a feeder to a remote panel, landed on the 3/0 AWG to 300 kcmil load lugs.
9) Does the Milbank M401-UG have GFCI outlets and a light built in, or do I add those separately?
Both are integral. Four NEMA 5-20 ground fault receptacles are built into the unit, and it comes with a light kit with photocell that switches on automatically at dusk. For a pedestal or jobsite power application that is the outlet group and the yard light already handled, with nothing to add.
10) Where do the grounding and bonding conductors land in the Milbank 320A meter main?
The M401-UG comes with two barrel ground lugs for equipment grounding, so the grounding electrode conductor and the equipment ground have factory terminations rather than an added kit. Since this is service entrance equipment with the main breaker in the can, the neutral to ground bond is made here and downstream panels are kept isolated.
11) Can the meter on a Milbank M401-UG be sealed and locked for utility service?
Yes. It is a ring type socket, so the meter is secured with a sealing ring, and there is a 7/16 inch knockout for a barrel lock provision if the utility or the owner wants a barrel lock on the cover. For a property manager worried about tampering on a tenant service, that knockout is the piece to point the electrician at.
How fast can I get the Milbank M401-UG-BS delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Milbank M401-UG-BS come with a warranty?
Absolutely. The Milbank M401-UG-BS is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Milbank M401-UG-BS?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
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