Wire brief · Building and service wire
SER and SEU cable: meter stacks and service upgrades
Both are service entrance cable and both are usually aluminium. One is flat with a neutral wrapped around the others; the other is round with four separate conductors. Neither is interchangeable.
Request a quote
Tell the desk what you have in SER and SEU cable
Send the basics and a buyer reviews the lot, usually the same working day.
- Reviewed by a buyer, not a scale
- Reels, pallets, partials or a full truckload
- Anywhere in Ohio, one desk
- 01Send the wire type, quantity and pickup city.
- 02A buyer reviews the lot and replies with a basis.
- 03Freight and release are agreed, then the load is booked.
Lot details
Everything helps, but the wire type, the quantity and the pickup city are enough to start.
Concentric neutral against four round conductors
SEU is the older form: two insulated conductors with a bare neutral spiralled concentrically around them, all under a jacket. It is a three-wire assembly, two hots and a combined neutral and ground, and it is what feeds most residential services and small commercial panels where the service disconnect is at the meter.
SER is the four-conductor round version. Two hots, an insulated neutral and a bare ground, laid up together and jacketed. It is used where the neutral and ground must be separate, which is any feeder downstream of the service disconnect: a subpanel, a detached building, a meter bank feeding tenant panels. The print on the jacket gives the size sequence, for example 2-2-2-4 aluminium, and that sequence is what a buyer reads first.
Why the concentric neutral changes the strip
On SEU the neutral is not a conductor you can cut and land separately. It is wound around the insulated pair, and at a termination it is unwound, dressed and brought to a lug. That means the ends of a used SEU coil are usually fanned out and work-hardened, and the last two feet of every length are compromised.
It also means the neutral counts as a current-carrying conductor in a way that surprises people who assume a two-conductor cable. When a lot of SEU comes in, the useful length is measured from behind the fan, not from the cut. On SER the conductors are parallel and the ends cut clean, so a coil keeps almost all of its length. On SEU the neutral is inspected as closely as the insulation, since a neutral that has been unwound and re-twisted a few times is the first part of the cable to give trouble.
Meter stacks, panel changes and the upgrade cycle
Service work generates this cable in a rhythm. A 100-amp service is upgraded to 200, the old SEU from the mast to the meter is replaced, and what comes down is a length of service cable that is still electrically sound but no longer the right size. A multi-tenant building replaces a meter bank and the risers to each apartment come out in matched lengths.
In Franklin County the same thing happens at scale on apartment rehabilitation and on commercial tenant fit-outs where an old single-meter service becomes a metered stack. Those jobs produce bundles of SER cut to a repeated length, which is a better lot than a single long coil, because the lengths are known and the ends are square.
Describing a service cable lot
Give the size sequence from the jacket print, not from memory. A reel marked 4/0-4/0-4/0-2/0 is not the same as 4/0-4/0-2/0, and the difference is a call back.
- Jacket print showing the full size sequence
- SEU or SER stated, and whether the neutral is concentric
- Copper or aluminium, with the conductor colour noted
- Length of each piece and whether ends are fanned or square
- Whether the cable was removed from an energized service
Related pages
Adjacent cities, wire families and regional briefs.
More in building and service wire
All wire typesQuestions sellers ask
Can aluminium SER be used for a subpanel feeder?
Yes, with lugs listed for aluminium and the correct antioxidant and torque. The cable itself is common in that role. What matters for resale is that the jacket print is legible so the size sequence can be confirmed, since the conductor colour alone will not tell you the gauge.
Is old SEU worth anything once the service is upgraded?
The copper or aluminium is, and a long clean length can be reused for a like-for-like service. Short pieces with fanned neutrals are usually recovery material. The dividing line is whether the length is long enough to reach from a mast to a meter can with the ends intact.
How do I measure a coil with a concentric neutral?
Measure the jacket, then discount the last couple of feet at each end where the neutral has been unwound. On a fifty-foot piece that discount is small; on a fifteen-foot piece it is most of the cable, which is why short SEU is rarely reviewed as reusable.
Request a quote
Tell the desk what you have in SER and SEU cable
Send the basics and a buyer reviews the lot, usually the same working day.
- Reviewed by a buyer, not a scale
- Reels, pallets, partials or a full truckload
- Anywhere in Ohio, one desk
- 01Send the wire type, quantity and pickup city.
- 02A buyer reviews the lot and replies with a basis.
- 03Freight and release are agreed, then the load is booked.
Second look at the lot
Everything helps, but the wire type, the quantity and the pickup city are enough to start.