Comparing cable types
SER, SEU and URD: service cable explained
Service cable is the cable between the utility and the building, or between a meter and a panel. The names describe where it goes, not just how it is built, which is why sellers often mislabel it.
SER and SEU are service entrance cables used above ground. URD is underground residential distribution cable, and USE-2 is underground service entrance cable rated for direct burial.
Above ground: SER and SEU
SER is a round, multi-conductor assembly with a bare neutral and an overall jacket, used for service entrances and for feeders to subpanels. SEU is the older two-conductor-plus-bare-neutral style, often flat or oval, used for single-phase service drops.
Both are commonly aluminum in residential work and copper in commercial work, and both are 600-volt rated.
Below ground: URD and USE-2
URD is a concentric or parallel assembly intended for underground residential distribution, usually aluminum. USE-2 is a single-conductor underground service entrance cable rated for direct burial and, in many constructions, for wet locations at 90°C.
If the cable was buried, say so. Buried cable is quoted on its condition and jacket integrity, not on the assumption that it is new stock.
| SER | SEU | URD / USE-2 | |
|---|---|---|---|
| Installation | Above ground, service and feeders | Above ground service drops | Underground, direct burial |
| Shape | Round assembly | Flat or oval | Concentric or parallel |
| Typical metal | Aluminum or copper | Aluminum or copper | Usually aluminum |
| Identification | Print reads SER | Print reads SEU | Print reads URD or USE-2 |
Questions about this
Can SER be buried?
Not as a general rule. Underground work uses URD or USE-2 rated for direct burial.
Is aluminum SER common?
Yes, especially in residential and light commercial service and feeder work.
Do you buy cable that has been buried?
Yes, with the condition disclosed. Photograph the jacket and the cut ends.