SEU wire stands for Service Entrance Unarmored cable. It is a specific type of electrical cable designed for particular applications within a building's electrical system.
Understanding SEU Cable
The acronym SEU provides direct insight into the cable's characteristics and primary function:
- SE (Service Entrance): This signifies that the cable is suitable for use as a "service entrance" cable. Service entrance cables are essential components that connect the utility power supply (from the meter or service drop) to a building's main electrical panel or distribution board. They are built to safely carry the primary electrical load into a structure.
- U (Unarmored): The "U" indicates that the cable is unarmored. Unlike some other service entrance cables (like SER, which stands for Service Entrance Round), SEU cable does not include an additional layer of metallic armor for mechanical protection. This design characteristic often makes SEU cable a more flexible and cost-effective option for installations where added physical protection is not required or where the cable will be installed within a protective conduit.
Key Characteristics and Uses of SEU Cable
SEU cable is specifically designed to meet National Electrical Code (NEC) requirements for service entrance applications. Here are some key aspects:
- Construction: SEU cable typically consists of two insulated phase conductors and a bare neutral conductor, all encased within a moisture-resistant and flame-retardant outer jacket. The conductors are usually made of aluminum.
- Applications:
- Overhead Service Drops: Running from the utility pole to the building's service mast.
- Underground Service Laterals: Used in conduit for underground connections from the utility source to the building.
- Feeder Cable: Can also be used as a feeder from a service panel to a sub-panel, particularly for applications like large appliances (e.g., electric ranges, clothes dryers) where the circuit requires specific conductor configurations.
- Installation: Due to its unarmored nature, SEU cable is often installed in conduit, raceways, or within wall cavities to provide necessary physical protection from damage. It is suitable for both wet and dry locations.
SEU vs. SER Cable
While both are service entrance cables, the key difference lies in their construction and shape:
| Feature | SEU Cable | SER Cable |
|---|---|---|
| Meaning | Service Entrance Unarmored | Service Entrance Round |
| Shape | Flat or Oval | Round |
| Armor | No metallic armor | Can have additional protection/jacket |
| Conductors | Often two insulated conductors with bare neutral | Two, three, or four insulated conductors with bare neutral |
| Flexibility | Generally more flexible | Often more rigid due to round shape |
| Typical Use | Service entrance, feeder to specific appliances (e.g., ranges, dryers) | Service entrance, feeder to sub-panels, general branch circuits |
For more details on service entrance cables, you can refer to resources like Wire & Cable Your Way: Service Entrance Cable (SER/SEU).
