Service entrance cables are electrical cables that connect and carry electrical currents from electrical companies to commercial buildings. They come in different types that serve various functions. Read on to learn what service entrance cables are and their primary characteristics.

Service Entrance Cables

There are two main types of service entrance cables: SER and SEU. SER cables are with a Style R reinforcement tape, and they typically deliver power from the service drop-down to the meter base to the distribution panel. SEU cables are most frequently used as panel feeders in branch circuit applications.

According to the National Electric Code (NEC), service entrance cables are designed to be used for services. All service entrance cables are produced, tested, and marked according to UL 854 standards. Service entrance cables for underground use are UL Type USE or USE-2, and service entrance cables for aboveground use are UL Type SE, Style R or U. 

Service Entrance Cable Characteristics

Aboveground service entrance cables are either SER or SEU. They have a moisture-resistant and flame retardant covering that enables them to easily pull through framing members and wooden joists in commercial buildings. Installation and application of all service entrance cables are specified by NEC Article 338.

Conductor Materials

service entrance cables

SEU and SER cables are manufactured with an AA-8000 series (ACM) electrical-conductor-grade aluminum alloy. Manufacturing underground UL Type USE and USE-2 cables that are not marked with any other type—such as RHH, RHW, or RHW-2—is done with an AA-8000 series (ACM) electrical-conductor-grade aluminum alloy or an EC-1350 grade aluminum alloy.

SER and SEU cables have different anatomies that make them suitable for various parts of a project. For example, an SEU cable has a neutral conductor but lacks a ground conductor. Because ground conductors and neutral conductors are only joined at the point of service disconnect, SEU cables are only safe to use at the point of disconnect. On the other hand, SER cables have both neutral and ground conductors, which makes them safe to use after the service disconnect.

Another difference between SER and SEU cables is their construction. SER cables are copper or aluminum wires reinforced with special Style R tape. SEU cables are Style U, which means they are unarmored and often used as panel feeders. Regardless of type, the installation of service entrance cables should always be done by a professional for safety reasons.

Service Entrance Cables From Classic Wire and Cable

Now that you have a good understanding of SER and SEU cables, the next step is to select a cable that fits your particular electrical project. With more than 200 years of combined cable and wire experience, Classic Wire and Cable’s experts specialize in serving electrical distributors. With warehouses in California and Pennsylvania and regional distribution centers throughout the U.S., we are always fully stocked with high-quality goods at competitive prices.

Ratings and Markings

See this table to learn more about our service entrance cable specifications.

Cable  SE Style R  SE Style U  USE Mobile Home 


Number of 


2c + Bare Cabled 3c + Bare Cabled 4c + Bare Cabled 2c + Bare Concentric  1c 3c + Insulated Ground

Conductor Size

8 AWG to 

300 kcmil

8 AWG to 

4/0 AWG

8 AWG to 

1000 kcmil

2 AWG to 

4/0 AWG



Thermoplastic (UL 83) 

Thermoset (UL 44) 

Thermoset (UL 44)
Conductor Types UL 83: THHN / THWN-2 

UL 44: XHHW 

RHH / RHW-2 / USE-2
Covering  Overall Tape-and-Finish  N/A  N/A
Covering Material  75 deg C PVC  N/A  N/A


Minimum Average: 30 mil 

Minimum Point: 25 mil 

N/A  N/A
Sunlight Resistant  YES  YES  YES  YES
Impact and 

Crush Tested 

Direct Burial  NO  NO  YES  YES
Joist Pull Tested  YES  YES  NO  NO
Overload Test  YES  YES

Selecting the right service entrance cable depends on the priorities of your electrical project. At Classic Wire and Cable, we offer a range of value-added services and use all available resources to make our customers’ projects a success. Contact us today for more information about our products and services.

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