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320A Service Panel Cost and 400A Residential Electrical Service

User question

What is a 320A service panel and how much does it cost?

Artificial Intelligence ResponseLABEL_AI_GENERATED

Direct answer to the question

A 320A service panel usually means a 320-amp continuous / 400-amp maximum residential electrical service, not a single ordinary breaker panel rated exactly 320A. In U.S. residential work it is commonly called “400 amp service” and is typically built with a Class 320 meter socket or meter-main feeding two 200A panels or two 200A service disconnects. Utility and manufacturer documents commonly describe Class 320 equipment as suitable for 320A continuous current and 400A maximum service use. (clarkpublicutilities.com)

Typical installed cost in 2026: about $5,000 to $12,000 for a normal 200A-to-320/400A residential upgrade, with difficult underground, trenching, long service runs, panel relocation, utility transformer/lateral changes, or major rewiring pushing it to $12,000 to $25,000+. Current 2026 contractor-pricing sources put 200A-to-400A upgrades, usually using a 320A meter and twin 200A panels, around $5,000–$12,000 installed; California-specific estimates are similar at $6,000–$12,000 for large or highly electrified homes. (pipelineon.com)


Detailed problem analysis

What “320A service” actually means

In residential electrical terminology, 320A service normally refers to the service entrance and metering equipment rating, especially the meter base, not necessarily to one indoor breaker panel.

A typical arrangement is:

  1. Utility service drop or lateral
    Power comes from the utility transformer by overhead wires or underground conductors.

  2. Class 320 meter socket / meter base
    This is the outdoor enclosure where the utility meter plugs in. Class 320 sockets are commonly rated 320A continuous, 400A maximum. Some utility handbooks explicitly state that a 120/240V, 400A residential service uses a Class 320 meter base when the continuous current is 320A or less. (clarkpublicutilities.com)

  3. Service disconnects or meter-main equipment
    The service may have:

    • one 400A main disconnect, or more commonly,
    • two 200A main breakers/disconnects.
  4. Two 200A distribution panels
    This is the most common residential layout. Instead of one huge 400A load center, the service is split into two standard 200A panels. Eaton, for example, describes Class 320A meter-main equipment with configurations using either a 400A main breaker or dual 200A breakers. (eaton.com)

So, when someone says “320A panel”, they often mean one of these:

Term used casually What it usually means in practice
320A panel 320A/400A residential service equipment
400A residential service Usually a Class 320 meter rated 320A continuous / 400A max
320A meter base Meter socket rated for 320A continuous service
400A panel upgrade Often two 200A panels fed from one 320A meter-main

Why 320A is associated with 400A

The 320A number comes from the continuous-duty rating. Many service components are treated as having a 400A maximum rating but 320A continuous capability. This is related to the common 80% continuous loading convention:

\[ 400A \times 0.80 = 320A \]

That is why residential “400A service” is often actually implemented with Class 320 metering equipment. Retail and manufacturer listings for 320A meter sockets commonly state 320A continuous, 400A maximum. (lowes.com)


Cost breakdown

Approximate installed cost

Scope Typical 2026 U.S. cost
320A meter socket / meter base only roughly $300–$900+
320A meter-main combination equipment roughly $1,000–$3,000+ depending on brand and configuration
Two 200A panels, breakers, grounding, conduit, fittings often $1,000–$4,000+ in materials
Standard installed 320/400A residential upgrade about $5,000–$12,000
Complex underground or utility-heavy upgrade $12,000–$25,000+ possible

One 2026 pricing source lists 200A-to-400A service upgrades, typically using a 320A meter with twin 200A panels, at $5,000–$12,000 installed. A contractor pricing page also lists 320/400A high-capacity service as a starting-price category, with site-specific factors determining the final quote. (pipelineon.com)

Why the cost varies so much

The panel itself is not the only cost. A 320A/400A service upgrade may require:

  • New Class 320 meter socket or meter-main.
  • New service entrance conductors.
  • New mast, weatherhead, riser, or underground conduit.
  • Two 200A panels or a meter-main plus subpanels.
  • New grounding electrode system, bonding, surge protection, and code corrections.
  • Permit and inspection.
  • Utility disconnect/reconnect.
  • Possible utility transformer, service drop, or underground lateral upgrade.

Trenching and utility-side work are often the largest unknowns; California 2026 cost guidance, for example, shows underground conversions or long trenches reaching $8,000–$15,000 and up, while 400A service for large electrified homes is commonly estimated around $6,000–$12,000. (reliable.work)


When a 320A service is used

A 320A/400A residential service is usually considered when a 200A service is insufficient after a formal load calculation.

Common reasons include:

  • Large home with multiple HVAC systems.
  • All-electric house with electric heat, heat pumps, electric water heating, induction cooking, etc.
  • Multiple Level 2 EV chargers.
  • Large detached garage, shop, barn, ADU, guest house, or pool equipment.
  • Solar-plus-battery systems, backup generator integration, or future electrification.
  • Existing 200A panel cannot support additional calculated load.

The correct engineering approach is not to guess based on panel fullness. The service should be sized from a load calculation, commonly under NEC Article 220 as adopted and amended by the local jurisdiction. Current cost guidance also emphasizes that the legitimate reason for an upgrade is a calculated load requirement, not simply that a panel is old or visually full. (reliable.work)


Practical guidelines

If you are pricing or planning a 320A service, ask the electrician for an itemized quote showing:

  • Whether the quote is for 320A continuous / 400A max service.
  • Whether it uses:
    • a Class 320 meter socket plus two 200A panels, or
    • a 320A meter-main with dual 200A breakers, or
    • a true 400A main service disconnect.
  • Panel brand and model.
  • Meter socket brand/model and whether it is utility-approved.
  • Overhead vs. underground service.
  • Whether utility fees are included.
  • Whether permit and inspection are included.
  • Whether grounding/bonding upgrades are included.
  • Whether trenching, concrete cutting, drywall repair, or siding repair is included.
  • Whether existing branch circuits are being moved or extended.

Before buying equipment, confirm approval with:

  1. Your utility — they often have an approved meter-socket list.
  2. Your AHJ — Authority Having Jurisdiction, usually city/county electrical inspection.
  3. A licensed electrician — service equipment errors can be dangerous and expensive to correct.

Possible alternatives

A full 320A/400A service is not always necessary. Alternatives may include:

  • Load management for EV chargers.
  • Smart panels or smart load-shedding devices.
  • EV energy management systems using current transformers.
  • Replacing electric resistance loads with heat-pump equipment.
  • Adding a subpanel if the issue is breaker space, not service capacity.
  • Reducing simultaneous demand by interlocking high-load appliances.

For example, if the reason for the upgrade is a single EV charger, a managed charger may be much cheaper than a full service upgrade. But if the home has multiple EVs, electric heat, large HVAC, a shop, and future battery backup, a 320A/400A service may be justified.


Brief summary

A 320A service panel is usually shorthand for a Class 320 residential service, commonly marketed as 400A service because the equipment is typically rated 320A continuous / 400A maximum. It is most often installed as a 320A meter base or meter-main feeding two 200A panels.

For cost, expect approximately:

  • $5,000–$12,000 for a typical installed residential upgrade.
  • $12,000–$25,000+ for difficult jobs involving trenching, utility upgrades, long underground runs, relocation, or major rewiring.
  • The only reliable way to know is to get a load calculation and an itemized quote from a licensed electrician coordinated with your utility and local inspector.

Disclaimer: The responses provided by artificial intelligence (language model) may be inaccurate and misleading. Elektroda is not responsible for the accuracy, reliability, or completeness of the presented information. All responses should be verified by the user.

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