What are MC3 and MC4 Connectors?

MC3 and MC4 connectors are single-contact electrical connectors commonly used for connecting solar panels. MC3 connectors are currently being phased out and replaced with newer versions. This is primarily due to their lack of lock in mechanisms.

What is the difference between MC4 and MC3 connectors?

The MC3s do not have a locking mechanism, so the energized connectors could easily disconnect on their own under a load, causing damage to the backside of solar panels. Therefore, MC3 connectors have gradually phased out and withdrawn by (NEC) the National Electrical Code for solar applications.

MC4 Connectors

Modern solar modules tend to use MC4 connectors. These connectors, for one, have a locking mechanism that prevents unintentional unplugging. Therefore, reducing the chance of damage to the backside of solar panels. To disconnect, press down on the two end clasps. This will release the connector. The durability of these newer connectors is substantial. They are age-resistant, UV resistant, corrosion resistant, dustproof, and waterproof, making a safe electrical connection. The concern for the connectors to become brittle, or to age at a faster rate, should be minimal to none.

Pre-Installed Connectors

All our panels at SanTan Solar come with pre-installed MC4 connectors. You will not need any tools to crimp the wires, creating a simple and faster solar wiring installation.

When to Use MC4 Connectors

MC3 and MC4
MC3 & MC4 Connectors

It depends on the solar panel’s size. Smaller solar panels (less than 20 watts) do not produce high currents, on the other hand, larger solar panels (more than 20 watts) withstand higher power levels. Larger solar panels are connected in an array. This creates a standardized termination that can handle higher voltages. As a result, the connectors must fit perfectly.


Modern solar panels use MC4 connectors. The benefits of the newer connectors outweigh the MC3 connectors ‘benefits’. The easy connection, disconnection, and durability of MC4 connectors create a simple solar installation. If you buy your solar panels from us, you will not need any tools to install your connector. This is because we pre-install MC4s on all our panels.

Interested in these connectors? You can find them on our website, under solar accessories. You can also learn more about solar panels and accessories by visiting our blog section.

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