About the Stäubli MC4 and MC4-Evo 2 Connectors
Stäubli MC4 connectors are the industry standard for photovoltaic quick-connect wiring. They create weather-tight, low-resistance contact points between solar panels, home runs, and equipment like charge controllers and combiner boxes.
Contact pins within the housing are crimped onto the PV wiring. The housing snaps over the top, with a weatherproof jacket sealing tight between the wire and the housing to prevent moisture from reaching the contacts. The insulating plastic housings lock together to keep the connection from pulling apart unintentionally. The Stäubli Open-Ended Spanner is required to unlock joined connectors. Only disconnect when panels have zero load to mitigate risk of serious injury or death.
Each set includes five plug ends and five socket ends (10 pieces total, five complete pairs). Use the Stäubli MC4 Tool Kit and follow the installation procedure to achieve an IP68 rating and maintain UL certification.
Materials and Construction
Stäubli MULTILAM contact pins are tin-plated copper. The insulating housings are PA (Polyamide) and PC (Polycarbonate), both durable and UV-resistant enough to withstand decades of direct sun exposure and weather.
Why Brand Matching Matters
MC4 connectors are designed to connect only to other MC4 connectors of the same model. Mixing brands or models can result in contact pins that don't seat properly, which creates an arc point and a fire risk. If you're extending or replacing connectors in an existing array, match the brand already installed.
Classic MC4 vs. MC4-Evo 2
The Classic MC4 is the standard connector used on the vast majority of residential and commercial solar installations. The MC4-Evo 2 is rated for higher voltage systems and is designed to withstand ammonia and salt mist spray, making it the better choice for coastal installations, agricultural settings, or any environment with high humidity or chemical pollutants.
A Brief History of the MC4
MC4 stands for "Multi-Contact 4mm," referring to the original manufacturer and the diameter of the contact pins. Multi-Contact released the original MC3 connector in 1996. Stäubli purchased Multi-Contact in 2002, though they kept the connector naming convention. The MC4 launched in 2004 with a larger contact pin and a locking mechanism.
In 2008, the National Electrical Code established that all PV connectors needed a locking mechanism. The MC4 became the dominant standard, and the MC3 was discontinued in 2016.
