Prefabricated wire wipes out related schedule risks on large solar projects

By Joe Parzych, eBOS Wire Product Manager, Terrasmart

The pandemic has led to unpredictable material costs and shortages. Add to that the constant challenge of balancing risk and reward and it’s an increasingly complex environment for solar EPCs and developers.

The numbers aren’t great. At present, 90% of all energy and energy infrastructure projects are either over-budgeted or delayed, according to a research by FMI Consulting. Analysts of the International magazine for innovation, management and technology say that construction projects in general tend to exceed budget by at least 16% – often much more.

Utility-scale PV construction is no different: Every minute and every cent counts.

So how do EPCs ensure solid project efficiency and returns? By ensuring that every detail is proactively addressed throughout the project lifecycle. Take a neglected eBOS part: wiring. By cutting back on cabling in the supply chain, you risk unforeseen delays and cost overruns in the final stages of a project that can hurt overall profitability.

Optimized electrical and wiring layouts, streamlined product deliveries and reliable partners are key to avoiding downstream challenges.

Key Considerations for Wiring Success

Consider prefabricated wire over bulk options. While bulk wiring may seem cheaper at first, prefabricated solutions tailored to meet a project’s unique layout will result in faster integration in the field.

Bulk, ready-made wires take longer to manually crimp, cut and install on site, which incurs labor and equipment costs. Using bulk wiring can also lead to inconsistent tolerances and inefficient use of materials and waste – and that is if all goes well. Incompatibility with wire connections in the final phase of a project can affect tight timelines and budgets at the end of the project when there is no slack in the schedule. Finally, wire fabricated in the field cannot provide the long-term consistency and reliability that is critical to asset owners and managers.

In comparison, prefabricated wiring can offset risks and deliver the following benefits:

  • Wire systems are assembled with precise combinations of wire gauges, harness lengths and combiner boxes.
  • In-house assembly means superior quality control for increased reliability and performance.
  • Controlled production shortens lead times and results in faster delivery.
  • Customized solutions simplify on-site execution and compress installation schedules.
  • Efficient plug-and-play connections are packaged for accurate installation in the field.

The end result is a high quality wire solution tailored to each project’s unique cost and scheduling requirements.

What to look for with an eBOS partner

Developing custom wire solutions requires solar experience. Be sure to select a wiring supplier who understands other PV components and has a global perspective on the project lifecycle. Most bulk wiring providers do not.

An experienced partner familiar with the complexity of projects, both upstream and downstream, can anticipate installation issues. Look for a wire supplier who can value engineering custom solutions based on unique project factors such as topography, rack height and number of modules. A cable supplier must be familiar with O&M practices and be able to design a wiring strategy that will support the long-term maintenance of the project.

There are additional benefits to working with eBOS partners who integrate wiring with other electrical components. In combination with a turnkey eBOS and assembly offering and in-house assembly, project pitfalls can be avoided, resulting in a smooth and coordinated process during implementation.

Project success story

When cranberry farmers in southern Massachusetts decided to go solar, they weren’t fully aware of the complexities of building an agrivoltaic system. Their hybrid system combined 9 MW of solar power with 36 MWh of storage and would be installed on a producing 150-year-old cranberry wetland (swamp).

Installing a system over fragile cranberry vines requires extreme caution and requires precise panel and wiring placement. The array had to be high enough not to interfere with the crops below and to allow farming activities such as harvesting to take place seamlessly.

That meant designing the system with some unique features:

  • Modules had to be mounted on 25 to 40 feet long wooden moisture-resistant utility poles that had to be driven 15 to 30 feet into the ground to raise the trackers 10 feet above the swamp. Significantly more wire was required at this height than a standard ground mounting system.
  • It was key to keep the cranberry swamps functioning fully and undisturbed; the wiring solution needed to minimize installation activities.
  • Wires had to be delivered within a tight timeline of six weeks instead of the usual lead times of eight to 12 weeks.

In collaboration with the developer and the EPC, the wire partner designed and delivered a custom solution to ensure the success of the project.

Wiring was combined with other BOS components to create a turnkey solution. The system took into account the unique height, placement, human activities and lead times of the project. And instead of waiting for the rack to be ready before installing the wiring, the partner placed the wiring next to the rack and module installations.

The added benefit of using a prefabricated wiring solution made installation quick. Approximately 1,300 source circuit conductors were cut to length and labeled at the factory. The wires were terminated with MC4 connectors installed at the panel end for quick connection to the combiners, and the bundles were sent to the site on coils.

Customized design and implementation delivers success

Using turnkey BOS experience and in-house assembly, the wiring partner was able to add unique value to this complex installation, delivering thoughtful coordination and simplicity on site. The custom, end-to-end wiring solution enabled rapid plug-and-play implementation, including:

  • Suitable for the atypical height above the peat with consistent and accurate cutting lengths.
  • Streamline wiring integration with combiner boxes.
  • Coordination with other components to shave weeks off the typical timeline for a project of this size and complexity.
  • Ensure prompt product delivery and wiring so construction did not delay harvest.

The result highlights the benefits of selecting a wiring partner with up-front problem-solving skills and expert estimators who can design custom solutions. Finding a flexible supplier with visibility into the entire process – from design and supply chain to production – delivers high-quality planning and solutions to mitigate project risk.


Joe Parzych oversees the wire division at Terrasmart — The new solar brand from the Gibraltar Renewable Energy Group that integrates SolarBOS with other companies, including (the former) TerraSmart, RBI Solar and Sunfig. With more than 15 million ft of wire installed, the group has a deep understanding of the solar project life cycle and an experienced team to manage project complexity and improve wiring layout efficiency. Terrasmart offers unique integration benefits to maximize efficiency and value while minimizing roadblocks and risk.

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