What are MC4 connectors?
MC4 connectors are single-contact electrical connectors commonly used for connecting solar panels. The MC in MC4 stands for the manufacturer Multi-Contact (now Stäubli Electrical Connectors) and the 4 for the 4 mm diameter contact pin. MC4s allow strings of panels to be easily constructed by pushing the connectors from adjacent panels together by hand, but require a tool to disconnect them to ensure they do not accidentally disconnect when the cables are pulled. The MC4 and compatible products are universal in the solar market today, equipping almost all solar panels produced since about 2011.
When and where are MC4 connectors used?
Generally, this depends on the size of the solar panel. While they are all designed to be weather resistant and UV proof for reliable outdoor use, their different sizes serve different purposes. Smaller solar panels (less than 20 watts) do not produce high currents. They are typically used as stand-alone units making the method of termination less significant. Larger solar panels (more than 20 watts), on the other hand, are designed to handle higher power levels. They are wired together in an array for standardized termination that can handle greater voltage. As a result, the MC4 connectors must fit perfectly.
How many parts does an MC4 connector have?
Each MC4 connector has five parts. They are the main housing, a metal crimp contact, a rubber water seal, a seal retainer and a screw on end cap. The male version of the MC4 connector uses a different housing and metal contact. The rest of its parts are interchangeable.
What tools are necessary when working with MC4 connectors?
Those who work with MC4 connectors need to use a few different specialized tools. The most important of them all is a crimp tool and two disconnect/spanner wrench combo tools. A must-have on any crimp tool is a hinged, swing out contact holder. It helps to make terminations uniform and on spec. It’s wise to avoid any crimp tools without this feature.