A solar array is all about connections—panels need to be connected to each other, and to inverters. Connectors attach solar components together to produce a successful flow of electricity.
On DC-based projects, panels must be connected into strings. Usually the connectors are installed on the panels at the factory, but they can be field-installed. End-panels have to then be connected to an inverter or combiner box, and those connections are often done in the field.
On AC/microinverter projects, connections are made between the panel and the microinverter. These connections are usually pre-installed with cabling, especially on plug-and-play integrated solar modules.
“Beyond their role in aiding electrical connections in PV solar arrays, connectors must meet the voltage and current requirements for their service while providing a low resistance point of contact,” said Daniel Sylawa, business development manager of renewable energy at Phoenix Contact USA. “They also must endure temperature extreme and thermal cycling, resist mechanical events and prevent disconnection for lifetime of the array.”
Connectors look especially simple, but they are very important. They require adequate engineering consideration to meet the requirements of a project. In addition to surviving extreme swings in outside temperatures, direct sun, snow and rain, connectors have to support increasing voltages. One of the biggest issues that prevents connectors from moving electricity from Point A to Point B is that not all of them mate together nicely.
“For both DC and AC project connector and cabling systems, no industry standards exist,” Sylawa said. “For DC systems, commonly a ‘MC4 connector’ is used. The MC4 design is a specific manufacturer which does not recommend mating with connectors of different manufacturers. The lack of an industry standard means that compatibly of the connection cannot be assured, especially over the 20- to 30-year lifetime of the array.”
Sylawa said a better practice is to use connectors from a single manufacturer to avoid complications. Most connectors, Phoenix Contact’s included, are designed to only mate with themselves.
Proper training is also a must when it comes to handling connectors, even though the act of connecting solar components together seems easy.
“DC PV connectors can have crimp style or tool-less spring style connectors for the wire connections,” Sylawa said. “Crimp style connectors are usually installed in a factory environment where proper tooling and trained installers are available. In the field, they can be problematic as often they are installed without proper tooling or training.” Tool-less spring connectors, therefore, offer an advantage as they have a self-intuitive installation procedure.
Connectors are one of the final pieces to a solar puzzle, and they’re just as important as the panels themselves. These small components shouldn’t be ignored; they’re essential to a successful project.