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11-MAY-2013
Solar MC4 Connectors
These are solar MC4 connectors the FEMALE on the bottom and the MALE plug on top.. Today more and more solar panels are shipping with MC-4 terminals and less and less with actual junction boxes. I still personally prefer a water tight j-box, and water tight gland nut, but not all panels ship that way.
The MC4 solar connectors are UL rated for 600V and up to 50A of maximum current. They also range from IP65 to IP68 rated (depends upon brand) which means they are fully "dust & water jet tight" (IP65) and can be submersed to 1 meter for 1 hour and still retain water resistance (IP68). The MC4 connectors are available in 14, 12, 10 & 8GA sizes.
MC4 Sizing:
14GA = 22.5A
12GA = 37A
10GA = 43A
8GA = 50A
They work quite well but on boats, but 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 could certainly be used for other applications.
Like any other project on boats this project will add yet another tool to your tool box.
11-MAY-2013
MC4 FEMALE / + Positive
These are the individual pieces of the FEMALE MC4 connector:
From Left to Right:
-Compression Nut
-Gland Compressing Ring
-Water Tight Sealing Gland
-MC4 FEMALE Crimp Terminal
-MC4 FEMALE Plug Body
11-MAY-2013
MC4 MALE / - Negative
These are the individual pieces of the MALE MC4 connector:
From L to R:
-Compression Nut
-Gland Compressing Ring
-Water Tight Sealing Gland
-MC4 MALE Crimp Terminal
-MC4 MALE Plug Body
11-MAY-2013
FEMALE & MALE
The FEMALE terminal on the left is ready to connect to the MALE terminal on the right.
11-MAY-2013
Insert FEMALE into MALE
I know it is confusing, the FEMALE vs. MALE with MC4's, because the one on the left clearly looks like a MALE and the one on the right clearly looks like a FEMALE.
The terminology relates to the crimp terminals inside the plugs not the body of the plugs. The plug on the right has the small male "pin" and the plug on the left has the FEMALE barrel/receptacle.
11-MAY-2013
Press & Snap Closed
You just press them together until the "snap" closed.
11-MAY-2013
MC4 Assembly & Dissasembly Tool
These are the MC4 assemble and disassemble tools. They are inexpensive and worth having especially for taking the terminals apart after they have been closed.
11-MAY-2013
MC4 Crimp Dies
OK here's where the extra tool cost comes into play. You will need a crimp tool for these terminals. However, as usual, I have located a very good value in an MC4 crimping tool (not the tool pictured). A pro who does this every day for a living would not use this tool because it is more tedious and time consuming than the more expensive pro-grade versions, which utilize a locator assembly,but for the money this tool preforms very, very well.
In full disclosure I imported a reasonably priced MC4 die set and crimping frame from Taiwan and while the dies are not pro-level you're not paying pro level pricing either. The tool represents a decent value for the budget minded boater at $46.95 (CURRENTLY ON SALE FOR $36.00).
11-MAY-2013
MC4 Crimp Dies Closed
Like a D-Sub style crimp tool the MC4 dies make a "B" or "butt-cheek" type crimp. The pictured die set is sized for 10, 12 & 14 AWG wire as well as 2.5 mm˛, 4 mm˛ and 6 mm˛ wire.
11-MAY-2013
Strip Outer Jacket From Cable
I will sometimes use a two conductor untinned round cable such as an SO type wire for the external connections to the solar panel but most often a tinned marine grade wire.. Inside these terminals the tinned wire is not as critical as with open style crimps. I almost always use 10/2 or 8/2 wire from the panel to deck if using MC4's. Once through a deck gland and into the vessel you can switch to a larger GA wire to minimize voltage drop.
Here I have stripped back the outer jacket of the wire exposing the inner 10GA conductors.
11-MAY-2013
Slide Heat Shrink Over Cable
To give the wire a nice finished look and feel I slide some heat shrink over the wire before I install the terminals.