Trenching to bury cable and wires on a large-scale, ground-mount solar array is generally easy enough. You dig a trench, lay the cable, fill the dirt back in. But trenching comes with its disadvantages. One, it’s dirty. Two, what if you hit rock? Three, those divots love to fill with water and make a muddy mess.
“We have seen excessive labor expenditures burying power cables in restrictive conduit underground when free air transit of cables is more cost efficient and eliminates the need to de-rate the cables’ capacity,” said Snake Tray President Roger Jette. “New paradigms in cable management brought from other industry sectors can make great cost effective solutions. There is no need to bury cables in expensive conduit underground anymore.”
CAB Solar, whose main division CAB Products (The Cambria County Association for the Blind and Handicapped) has manufactured hooks and hangers commonly used to hold aerial cables or traffic signals over intersections, manufactures solar hangers for use along a messenger wire or guy strand strung between piers/supports spaced generally 15 to 20 ft apart.
“Up until a couple years ago most companies trenched their wire and cable, but with trenching you end up with many disadvantages, from water filling up in the trenches to hitting hard rock,” said Allen Smith, general manager for CAB Solar. “With a 6-in. rainfall, all the trenches are full of water. [Hangers] have made life a lot easier for these large utility-scale PV arrays.”
CAB Solar makes dozens of different styles of hangers to hoist solar cables above the ground. The cable size determines which hanger style to use, and Allen said there is no weight limit for the hangers. Hangers easily hook into place and support the solar cables every 12 to 30 in.
“The hangers are made with individual carriers to keep wiring separated,” Allen said. “[Installers] hang the hanger and then load it with wires, and once the wiring is all loaded, just close it up.”
Spacing and positioning of the messenger wire is probably the most important step when using hangers for wire management. Post-installation maintenance must be kept in mind (think weed abatement) and wires must be positioned above any problem areas.
Snake Tray’s cable trays can also attach via a messenger wire, like the Solar Snap Snake Tray for Messenger Wire or the Solar Messenger Wire Snake Tray. The Utility-Grade Solar Snake Tray mounts horizontally to the array. All Snake Tray products are bendable by hand for easy installation and can come in single or double pocket designs.
“Newer systems are asking engineers to carry voltages upwards of 1,000 volts at very high amperages,” Jette said. “Cable management is no longer just a clip and run scenario. Installers need to consider the hazards of unmanaged cable.”
Both CAB Solar and Snake Tray have cable management products that are quick to install, and videos online from both companies show the easy installation process.