What Is 2-2-4 Aluminum Wire Used For? | SER, SEU, And URD Explained

2-2-4 aluminum wire is most often used as a service entrance or feeder cable, carrying 120/240V power from a meter base to a 100-amp main panel or subpanel.

Run the wrong spool of 2-2-4 from a meter base to a subpanel and the inspector flags it before the trencher is even cleaned up. The designation on the jacket — SER, SEU, USE-2, or URD — decides where that cable can legally live, and whether it can sit in wet earth or has to stay inside a dry wall cavity. Get the marking right and the same size conductor powers a garage, a mobile home, or a whole service upgrade.

The short version: 2-2-4 aluminum is a 100-amp-class feeder cable, rated 600 volts and typically 90°C, and its allowed locations shift with the exact product type stamped on the jacket.

What Does 2-2-4 Aluminum Wire Actually Power?

2-2-4 aluminum wire feeds a main breaker panel, a subpanel, or a dedicated heavy load — it is not branch-circuit wiring for outlets and lights.

Sellers consistently name the same jobs for this cable: meter-base-to-panelboard runs, residential service upgrades, detached garages, workshops, basement additions, HVAC equipment, electric water heaters, ovens, and mobile or manufactured homes. The three “2” conductors are the two hots and the neutral; the “4” is the equipment ground conductor in assemblies built that way.

Southwire’s product page for Type SER says the cable is primarily used to convey power from the service drop to the meter base and from the meter base to the distribution panelboard, and may be used where Type SE cable is permitted. That single sentence covers the most common job: the main feed into a house.

Southwire’s mobile-home feeder page describes a different build of the same conductor size, intended for connecting mobile homes to a supply of electricity where permanent wiring is required by the NEC, and suitable for direct burial in earth at conductor temperatures up to 90°C.

SER, SEU, USE-2, Or URD: What Decides The Outcome

The letters on the jacket, not the 2-2-4 number, decide whether a cable can be buried, run in conduit, or must stay in a dry location.

This is where most mistakes happen. Listings for 2-2-4 aluminum appear under several names — SER, SEU, USE-2/RHH/RHW-2, mobile home feeder, underground residential distribution (URD), and underground secondary distribution cable — and those constructions are not interchangeable.

• SER and SEU: service entrance cable for feeder runs, frequently limited to dry locations depending on the listing.
• USE-2 / RHH / RHW-2: rated for wet locations, and the mobile home feeder version can go direct in earth.
• URD: a quadruplex underground build; one listing shows 153 A direct burial and 115 A in duct, which is why ampacity has to be read off the specific product.

Treating every 2-2-4 spool as interchangeable for direct burial or wet locations is the classic error. Some product pages explicitly restrict use to dry locations while others permit burial, so the install method has to match what the jacket actually says.

Aluminum also behaves differently from copper at terminations — Code Check’s aluminum wire technical bulletin covers the connection and termination practices that keep aluminum feeders reliable — but the cable type question comes first, and comparing 2-2-4 aluminum wire options by type settles it fast.

Is 2-2-4 Aluminum Wire Always A 100-Amp Cable?

No. Many listings market 2-2-4 as a 100-amp cable, but the real ampacity depends on the cable construction and how it is installed.

The 100A label is the common shorthand because 2-2-4 aluminum in SER or mobile home feeder form is widely used for 100-amp service and subpanel feeds. That shorthand breaks down the moment the construction changes. A URD-style quadruplex listing showing 153 A direct burial and 115 A in conduit proves the point: same conductor size, different number.

Voltage rating is steadier across products — 600 volts appears on multiple spec sheets — and 90°C is repeated for wet or dry locations depending on cable type. Ampacity is the moving target, and it moves with burial depth, conduit, and the exact jacket marking.

Before buying, confirm three things on the product page: the cable type letters, the permitted locations, and the ampacity for your install method.

What Do You Check Before You Buy?

Match the cable marking to the install location first, then confirm the ampacity number for that exact product.

Read the listing like a spec sheet, not a search result. Look for the conductor description — compact stranded aluminum alloy is common — the insulation type, and the ground conductor size, which runs 4 AWG in many 2-2-2-4 assemblies. Confirm the temperature rating and whether the product is approved for wet locations, conduit, or direct earth contact.

If the page says dry locations only, it means dry locations only, no matter how the job site looks that day.

Then check what your local code authority requires for the specific feeder you are running. The NEC sets the baseline, and local amendments and inspection practices decide the rest, which is why the same cable can pass in one jurisdiction and fail in the next.