Cable reels on data center construction

Why data centers produce so many empties

A large data center is a power plant's worth of electrical gear inside a building. Power comes in at medium voltage from an on-site or nearby substation, runs through switchgear and transformers, then out on large low-voltage feeders to UPS systems, power distribution units and generators, with miles of grounding conductor and branch wiring behind them. A second network of fiber ties the halls together. Nearly every foot of it arrives on a wooden reel.

The Edison Electric Institute names data centers first among the reasons its member electric companies expect to invest more than $1.1 trillion over 2025 to 2029, after a record $178.2 billion in 2024. Some of that is the substations and lines that feed these sites. The rest of the cable is bought by the electrical contractor, and the reels land on the contractor's jobsite.

The reels each part of the build uses

Each kind of cable has a drum it needs. Under the NEMA WC 26 minimums Anixter reprints, shielded medium-voltage cable needs a drum 14 to 20 times its diameter, nonshielded 600 volt cable 10 times, interlocked armor 14 times, and fiber 20 times and never less than 12 inches. That sorts a data center's reels roughly as the table shows. Sizes are representative published reels, not a complete list.

Why the lots are good and the pickups are not simple

Data center reels make clean lots. Projects standardize cable, so a site can end up with many reels of one feeder size and many of one MV size. The reels are often indoors or in a fenced laydown yard, so they weather less than reels on a utility right-of-way. A trailer of one size loads tight: Sonoco's packing guide counts 120 of its 42 inch reels or 60 of its 54s in a 53 ft van.

Getting them out is the hard part. Sites are secured, with badging, escorts, delivery windows and safety orientations for drivers, and the general contractor wants empties out of the building on its schedule, not the truck's. Tell us the rules before we book a truck, and we will schedule around them.

1. 01

   Count by size

   Flange x traverse x drum and count for each size, from stencils or a tape.

2. 02

   Give us the site rules

   Gate address for the driver, delivery windows, escort and orientation needs, and the dock or forklift available.

3. 03

   Stage the empties

   Move reels to one spot on their flanges, nested in rows, so the truck loads in one visit.

4. 04

   Confirm the date

   We quote the lot with freight in it and book a truck to fit the window.

Respooling surplus cable on site

Large electrical jobs end with partial reels: the last 600 ft of a 500 kcmil feeder, or a few thousand feet of fiber left from the backbone. The contractor wants that cable off the expensive reel it came on and onto something that can be stored, returned to the warehouse or used on the next phase. That is the main reason data center contractors buy empty reels from us.

Pick the reel by drum first. A 1.25 inch nonshielded feeder needs a drum of at least 12.5 inches under NEMA's 10 times rule; a 0.75 inch fiber cable needs 15 inches at 20 times, or 22.5 inches if the maker asks for 30 times, as Corning does. Then check footage with the NEMA formula from Anixter's handbook, Footage = 0.262 x T x (H - C) x (D + H - C) / d squared. By that formula a 42x26x18 holds about 1,221 ft of 1.25 inch cable and a 48x28x24 about 1,596 ft. Last, check weight: Okonite rates its lighter 42x26x18 for about 1,500 lb of cable and the heavier build for about 3,000 lb.

Phased campuses and repeat lots

Many data center campuses are built in phases, one hall or building after another. Each phase empties reels and each phase needs a few for respooling, so the same site can sell us empties in one month and buy reels the next. We can keep the lot write-ups from each phase on file so a contractor can see what sizes it has given off and what it may need again, and so freight can be planned around the campus rather than one load at a time.

What lowers the value of a data center reel

• Split or wallowed arbor holes from heavy payoff work
• Flanges cracked by a forklift or a dropped full reel
• Missing staves, or staves broken by a jack
• Lagging nails, banding and pulling-eye hardware left on the reel
• Cable tails left on the drum
• Mixed sizes stacked together so that nothing nests

Returnable reels on the same site

Not every reel on a data center job is a wooden non-returnable. Large MV cable sometimes ships on steel reels, which Southwire, for one, lists as returnable with a charge, and those go back to the maker. Some cable makers take back their own wooden reels by the full truckload, such as Service Wire, which accepts only its own labelled 30 to 72 inch nailed reels with sound arbor holes and at least 75% of staves. Sort those out first. Everything else is a reel lot we can price.