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How to evaluate used MV cable, pad-mount transformers, and BoP gear.

A procurement engineer's checklist. Reel records, megger interpretation, jacket inspection, partial-discharge testing, and the freight + handling realities that make collection-system reuse work. The unglamorous category that drives 20–30% of project BoS spend.

By the Refound team Last updated April 2026 Read online, or print to PDF

Collection systems and balance-of-plant gear get the least attention in utility-scale procurement, but they represent 20–30% of total project BoS spend. They're also where project-surplus inventory most often ends up scrapped or stored indefinitely after a cancellation or downsize. The reuse opportunity is huge — most of this inventory is genuinely new, never deployed, and sitting on a laydown yard waiting for its second life.

That said, "new in the original wrap" can mean "five years on a yard pad through five winters." Every reel, every pallet of splice kits, every pad-mount transformer needs structured evaluation before deployment. This guide walks through the evaluation sequence Refound recommends for each major BoP component class.

Before you bid

Collection-system procurement starts with a clear understanding of project compatibility. Cable specs in particular are not interchangeable across MV voltage classes, conductor sizes, or insulation systems. Confirm:

MV cable on reels

The most common collection-system listing on Refound is medium-voltage cable on reels. Sources are typically project surplus (most reels never deployed), repower-decommissioned (rare for cable, more common for accessories), or OEM excess inventory.

For each reel, demand:

For reels that have been in outdoor storage longer than 5 years, expect to repeat the megger test before deployment regardless of the seller's records. Cable insulation tolerates outdoor storage better than most BoP gear, but it's not invulnerable.

Megger + insulation tests

Megger insulation resistance is the single most informative test on used MV cable. The basic procedure: apply a DC voltage (typically 5 kV for 15 kV class cable, 10 kV for higher classes) between conductor and shield, measure leakage current, calculate insulation resistance:

For high-pot tests on previously-installed cable, follow IEEE 400 guidelines for the test voltage and dwell time. Modern very-low-frequency (VLF) high-pot is the preferred test method for installed-cable verification; DC high-pot is more aggressive and can damage already-aged cable.

Partial discharge (PD) testing is the gold standard for cable insulation evaluation but requires specialized equipment and trained operators. Most secondary-market cable transactions don't include PD data; for revenue-grade installations, plan to do PD testing post-installation.

Splice kits + accessories

Cable accessories — splice kits, terminations, separable connectors, T-bodies, elbows — are the highest-shelf-life-risk items in BoP procurement. Cold-shrink and heat-shrink kits have manufacturer-specified shelf lives:

Beyond the manufacturer's shelf life, the rubber compounds lose elasticity and the inhibitor compounds migrate. A 6-year-old cold-shrink kit installed today will fail prematurely. Refound's collection-systems listings require accessory listings to carry the manufacture date stamp; refuse purchases without that data.

Storage condition matters too. Indoor controlled-temperature storage extends shelf life. Outdoor storage in a laydown yard does not. Ask for storage-condition photos.

Pad-mount distribution transformers

Pad-mount transformers (typical 25 kVA – 2.5 MVA, primary 12.47 / 13.8 / 25 / 34.5 kV, secondary 480 / 240 V) are a strong reuse category. Most utility cycle-outs are driven by load growth requiring an upsize — the existing transformer is operationally fine. Evaluation checklist mirrors the power transformer process at smaller scale:

For pad-mounts manufactured pre-1979, PCB testing is mandatory regardless of the seller's representation. Mineral-oil transformers from that era have a non-trivial probability of PCB contamination.

OPGW + ADSS fiber

Fiber-optic cable in the collection system serves SCADA + protective relay communications. Two main types in utility use:

For either type, demand:

Conduit + raceway

PVC, fiberglass, and steel conduit + raceway is one of the cheapest-per-foot items in BoP but the volume per project is enormous. Project-surplus reuse mostly comes down to:

Conduit bodies, fittings, and accessories follow the same rules. Reusable if dimensions match; less risk than cable accessories because the materials don't have shelf-life issues.

Freight + handling

Cable freight scales with reel size + count. A few practical anchors:

For partial reels (under 50% of original length), expect a 15–25% per-foot premium over full-reel pricing because of cable cutting + re-spooling labor. For partial pallets of accessories, expect an LTL freight premium.

Always verify the receiving site has a forklift with sufficient capacity (8,000+ lb for full reels of MV cable) and rigging support for any pad-mounts > 1 t.

Shelf-life management

The single most under-appreciated risk in BoP procurement is the shelf life of polymer-based components. A summary:

Demand manufacture-date stamps on every accessory pallet. Refuse purchases without the date stamp; the price discount can never compensate for a failed splice in service.

Common red flags

Pre-bid checklist

Collection-systems procurement rewards documentation discipline. The accessories with the longest shelf lives, the cable with the cleanest megger results, and the pad-mount transformers with the most complete test data deliver the least risk per dollar. Pricing should reflect that hierarchy, not just the per-foot or per-kVA headline.