Solar MC4 Connectors
These are solar *MC4 connectors, the FEMALE is on the bottom, and the MALE plug is on top. Today, more and more solar panels are shipping with MC4 terminals and less and less with actual junction boxes. I still personally prefer a water tight j-box, and water tight entry gland, but not all panels ship that way.
*IMPORTANT: Technically these are fake/knock off MC4 connectors. They were used to keep the cost of this article as low as possible while not destroying the more expensive, and much higher quality, Stäubli Multi-Contact branded MC4 connectors. MarineHowTo.com, DOES NOT RECOMMEND using knock-off MC4 terminals.
Genuine Stäubli MC4 solar connectors are UL rated for 1000V DC and up to 30A of maximum current using 10GA wire. The term MC4 stands for “Multi-Contact“. Multi-Contact / Stäubli Electrical Connectors is the German manufacturer, they invented the MC4 connector and resulting standard followed. Genuine Stäubli made MC4’s are IP68 rated which means they are fully “dust & water jet tight” and can be submersed to 1 meter for 1 hour and still retain water resistance (IP68). The Stäubli MC4 connectors are available in 14, 12, 10 & 8GA sizes. Don’t get your hopes too high, of finding the 8GA terminals, or a crimp tool to terminate these, which is less than about $500.00..
14GA = 22.5A
12GA = 37A
10GA = 43A
8GA = 50A
Genuine Stäubli made MC4’s work very well, but on boats, if not carefully installed, they can be a tad bulky and prone to being caught on things. That said, they are one of the better water tight electrical connections available for marine use. You don’t have to use them only on solar connections and they can certainly be used for other applications.
Like any other project on boats this project will add yet another tool to your tool box.
NOTE: Please click on any image to make it larger.