Solar Site Layouts: A Leap Forward in Efficiency and Sustainability

Written by John Brown, Paige Renewable Engineering Manager

The design and cabling infrastructure of utility solar sites have evolved significantly, moving from the traditional method of running single-circuit (panel string) cables underground to the more efficient and scalable approach of combining circuit cables above ground in advanced, messenger systems. This shift is not just about convenience; it brings technical benefits that enhance both performance and sustainability.

In the early days, underground, single-circuit strings were the norm, but they presented several challenges. By design, every panel string (which consists of multiple panels wired in series to build voltage) had to be extended hundreds—sometimes thousands—of feet to a combining location called a combiner box. At this location, the circuits were combined to build current—every string having a pair of cables. If a block had 500 strings, there were 500 pairs of copper extender cables to fabricate and install. Copper cable is a commodity sold by the foot. The more feet, the more cost. The first step in the evolution involved combining string locally in the field to take advantage of slightly larger extender cables. While larger, there was only one-half to a third as many cables. Less copper, more efficient use of copper, and less labor to install fewer feet of copper, resulted in less cost.

Today, solar farms are adopting new technologies, which greatly simplify the installation and maintenance process. Two of the main technologies are above-ground installation in messenger systems and bus systems. Above-ground installation allows for faster visual inspections and easier access should any maintenance be needed; it also reduces trenching, shortens cable length, and allows for a simpler, more cost-effective install—especially in difficult terrain.

Perhaps one of the most economical and efficient technologies being developed and used today is an old concept updated and applied in modern, innovative ways. It’s called the Trunk Bus System. Panel circuits are tied to a localized cable trunk called a bus. Power lines are a type of bus distributing power at local taps as they run down the street. A trunk bus is the same technology in reverse. Power from individual panel circuits is tapped into a common, larger bus made of aluminum. This bus is less expensive per pound, easy to install, and greatly reduces the number of individual cables as many long cables are now shortened and tapped into a much larger, common bus. The trunk bus is run to a device called a Load Break Disconnect, allowing for disconnection from the field for maintenance. The overall concept is to reduce string wires and extenders as quickly as possible. Again, less copper, less cables, less labor, equals less cost. These reductions also produce a more secure, simplified system.

At Paige Renewable Energy, our approach to the Trunk Bus technology relies on a product known as an Insulation Piercing Connector (IPC). 

While some bus systems must be carefully designed, custom pre-fabricated and carefully installed to a very rigid and costly design, the IPC system uses commonly available 2KV trunk cable cut to length in the field as needed. IPC taps are installed at convenient locations determined in the field once wire management is complete. This on-the-fly approach reduces waste, cost, and design complexity—once again decreasing cost.

By embracing these innovative layouts and utilizing next-generation cabling solutions, solar sites today are more efficient, scalable, and sustainable than ever before—providing more power with fewer risks and lowering the total cost of ownership. Paige Renewable Energy is proud to be at the forefront of this evolution, delivering products designed to support the solar infrastructure of tomorrow.