Photovoltaic connectors, also known as MC4 or H4 connectors, play a pivotal role in facilitating rapid connections between junction boxes, convergence boxes, components, and inverters within photovoltaic systems. Despite their relatively small size in the overall system, a lack of attention to their selection, processing, and compatibility considerations can lead to significant issues. According to statistics, connector damage or overheating ranks as the second most common cause of power generation loss among various failures in power stations.

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  1. Performance Requirements of Photovoltaic Connectors

So, what are the essential performance requirements for photovoltaic connectors?

a. Electrical Conductivity: Photovoltaic connectors must exhibit excellent electrical conductivity, with contact resistance not exceeding 0.35 milliohms. b. Safety: Photovoltaic connectors need to provide sufficient safety features to ensure the integrity and safety of solar modules. Given the diverse environmental conditions where solar equipment is used, connectors should be waterproof, heat-resistant, corrosion-resistant, and have high insulation performance, with a protection rating of at least IP68. c. Mechanical Integrity: The structure of solar connectors should be robust and reliable. When male and female connectors are correctly plugged together, the connection force should not be less than 80 N. For MC4 connectors handling 4mm² cables and carrying a current of 39A, the temperature must not exceed the upper limit of 105 degrees Fahrenheit. MC4/H4 connectors, which belong to single-core connectors, come with the advantages of good sealing, ease of connection and plugging, accessibility, and straightforward maintenance.

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  1. Installation Precautions for Photovoltaic Connectors

When installing photovoltaic connectors, it’s crucial to observe the following precautions:

a. Product Quality: Ensure that the connectors meet quality standards, including the compliance of internal metal conductor size, material thickness, elasticity, and plating for carrying large currents and ensuring good contact. The connector’s plastic shell should have a smooth and crack-free surface, and the interface sealing must be effective. b. Avoid Exposure: Install component connectors in areas shielded from direct sunlight and rain to prevent premature aging of the joints, internal connections, and cable rust. Such issues can increase contact resistance and, in extreme cases, lead to ignition, reducing system efficiency or causing fire accidents. c. Crimping: Proper crimping is vital during PV connector installation. Professional crimping tools should be used, and installers should receive adequate training before construction begins.

In recent years, as photovoltaic cell technology has advanced, individual PV module capacities have increased, leading to higher string currents. While MC4/H4 connectors are theoretically designed to handle these capacities, there have been cases of connector melting, overheating, and even failures leading to convergence box and inverter issues.

As such, it’s important to recognize that despite their small size, connectors are integral to the proper functioning of a PV power generation system. Especially during the operation and maintenance phase after power plant completion, attention should be focused on their operational status. Regular checks should be conducted to identify any signs of abnormal warming or other irregularities to ensure proper and efficient operation.

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In conclusion, photovoltaic connectors may be small components in a PV system, but their reliability and performance are vital for maximizing power generation efficiency and minimizing the risk of accidents and fires.