Understanding Solar PV Wire Management
One of the most important tasks when installing a PV system is wire management. This task is sometimes overlooked by installers or not given enough attention. Installers that take their wire management seriously will have longer lasting systems that require less maintenance over the lifetime of the PV system (20 to 30+ years).
So, what is wire management? Wire management is the practice of properly routing, organizing, supporting, and protecting the wiring. This practice is especially important for the installation of PV systems given the variety of harsh environments that PV systems are installed in.
Properly routing wiring refers to running conductors in a manner that avoids damage to the wire’s insulation and conductor. Things to avoid are sharp edges and rough surfaces, overly tight bending radii, overly tight size of cable clips, moving parts of racking systems, direct exposure to sunlight, potential damage by local critters and sagging wires.
Properly organizing wiring refers to grouping, routing and labeling wires in a manner that can make for easy identification of different circuits for future maintenance personnel as well as for emergency personnel. Using wire that has colored insulation not only is required by the NEC, but also provides for better identification of circuit conductors. Labeling strings, DC and AC circuits within junction boxes is another good practice allowing for better troubleshooting by future maintenance personnel.
Properly supporting wiring refers to the practice of securing wiring either along PV modules and racking equipment or in conduit trays. Accomplishing this task requires choosing the appropriate components to do so. These components include stainless steel wire clips, UV-stabilized composite wire clips, UV-stabilized wire ties or a cable tray.
Stainless steel wire clips are available in a variety of forms to meet a variety of needs. These clips are designed to fasten to module frames or mounting rails. They are designed to clamp a single or multiple USE-2, PV wire or TC-ER cables. Some manufacturers of stainless clips provide 90-degree clips where the surface length being clipped to is perpendicular to the route of the cable.
Many manufacturers such as IronRidge, Unirac, Enphase, to name a few, make UV-stabilized composite cable clips that attach to the mounting rail. These clips support a variety of wire types and quantities ranging from single wires to many wires. When clips and cable ties are not able to provide sufficient support, conduit and cable trays should be utilized. Choosing an appropriate conduit material, size and route should be done according to the NEC and local regulations. Finally, although not directly considered wire management, array edge screens are a great tool to keep rodents and other critters from gaining access to PV array wiring for habitual chewing
To conclude, wire management is the process by which to properly route, support and protect the wiring of your PV system. Giving a little extra attention to choosing proper components to achieve this task will go a long way, especially over the life of the system. Drop those white and multi-colored nylon zip ties and choose appropriate equipment to secure your wiring in place. If needed, include conduit, wire trays and even array edge screens to provide protection from physical damage. Your customers will be happy with their system when they realize that they haven’t called you 5, 10 or even 15 years down the road to repair a troublesome system where poor (a lack thereof) wire management is the cause of damage.