What Is 4/0-4/0-2/0 Aluminum Wire Used For? | Service Feeder Basics

4/0-4/0-2/0 aluminum wire is a service entrance and panel feeder cable that carries power from the utility connection to your main breaker panel.

If an electrician told you your new 200-amp service needs 4/0-4/0-2/0 aluminum, this is the cable they meant. It moves electricity from the meter base to the main distribution panelboard, or from that panel to a subpanel. The numbers describe the conductor sizes: two 4/0 hot conductors plus one 2/0 neutral, all wrapped in a single jacket. This configuration is rated for 600 volts and is approved for 120/240-volt residential and light-commercial service.

The practical question is where it’s actually allowed to run, and that depends on whether you’re holding SER or SEU cable on the spool. Here’s what each one does, plus the code rules you can’t skip.

Core Applications: Service Entrances, Feeders, and Mobile Homes

4/0-4/0-2/0 aluminum cable does one job well: carries large amounts of power between fixed electrical equipment. The three most common jobs are:

• Main service feeds — from the meter base or utility disconnect to the main breaker panel.
• Subpanel feeders — from the main panel to a secondary distribution panel elsewhere in the building.
• Mobile-home feeder and service-entrance use — supplying power to manufactured homes and other structures with their own panel.

Multiple-dwelling panel feeders, like the risers feeding individual apartment units, use the same cable. On retail listings, this wire is commonly rated 200 A for SER and 205 A for SEU, though the actual allowable ampacity depends on the termination temperature rating, installation conditions, and the specific code rules that apply to your setup.

If you’re comparing options before buying, our tested roundup of the best 4/0-4/0-2/0 aluminum wire spools covers the lengths and brands worth your money.

SER vs. SEU: Which Cable Type Fits Your Job?

Both SER and SEU share the 4/0-4/0-2/0 conductor arrangement, but they are rated for different installation locations and you can’t swap them freely.

SER (service entrance cable, round) is the above-ground workhorse. Southwire’s spec sheet describes it as a service entrance cable for use in wet or dry locations, and it’s the version you’ll see on most residential meter-to-panel and panel-to-subpanel runs. Its temperature rating is 90°C in wet and dry locations, though terminations may limit practical use to lower temperatures depending on the equipment and circuit rating.

SEU (service entrance cable, flat) is used for panel feeders and branch circuits. It has the same 600-volt, 90°C rating but a flat profile that can be easier to route in tight spaces.

One hard rule applies to both: SE cables are not permitted underground, with or without a raceway, per NEC 338.12(A)(2). If your run goes below grade, you need a different product family entirely, like URD cable or conductors in conduit.

The Naming Trap: 4/0 Configurations That Look Alike

Here’s where buyers get burned. 4/0-4/0-2/0 describes only the three main conductors, and similar-sounding cables are not interchangeable:

• 4/0-4/0-4/0-2/0 SER adds a third 4/0 ungrounded conductor plus a separate 2/0 ground — a different assembly for different needs.
• 4/0-4/0-2/0 SEU matches the three-conductor count but uses the flat SEU construction.
• 4/0-4/0-2/0 URD / mobile-home feeder is a separate product family rated for underground burial, not for above-ground service entrance use.

Do not assume the “4/0-4/0-2/0” string alone is enough to choose a cable. The exact assembly, grounding conductor, insulation rating, and permitted installation location all determine whether the install passes inspection. When in doubt, the nameplate and the product page — not the shorthand — are what count. Southwire’s SER aluminum service entrance cable documentation spells out the ratings and approved uses for its offerings.