What Is An MC4 Connector?

MC4 connectors are single-contact electrical connectors. They are commonly used for connecting solar panels. MC4 stands for “Multi-Contact, 4 millimetre”. It is a standard in the renewable energy industry. An MC4 connector enables the easy construction of strings of panels. In today’s solar market, both MC4 connectors and their compatible products are used across the board. For the most part, larger solar panels will already come equipped with MC4 connectors. They are manufactured by Multi-Contact, which is the official manufacturer of MC4 connectors. Solar panels are plastic-based round housings with single conductors in paired male/female configurations. With the help of a notched interlock, MC4 connectors are able to terminate to each other and avoid being unintentionally pulled apart.

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. Some MC4 connectors have removable safety lock clips. They cover the interlock tabs and provide additional unintentional disconnect protection.

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.

Which wires are needed for MC4 connectors?

Most wires needed for MC4 connectors are advertised as solar panel wires or photovoltaic wires. Although there is a variety to choose from, it’s important that they all meet National Electric Code (NEC) requirements. It’s also imperative that they meet Underwriter’s Laboratory (UL) standards for UV resistance. Wires that are not UV resistant are not approved for outdoor use. Beware of “MC4-compatible” connectors. They are not manufactured by Multi-Contact. While they may appear cost-effective, these imitation connectors often do not meet the same safety certifications and engineering standards as authentic MC4 connectors. Because these knock-offs have proven to be a problem in the industry, Multi-Contact has actually issued a formal statement about them. For more information about MC4 connectors, please don’t hesitate to give Flux Connectivity a call at 1-800-557-FLUX or email us at connect@fluxconnectivity.com.