How to Make MC4 Solar Connectors
Learn how to make your tightly coupled MC4 solar connectors with these accessories.
Don't feel bad if you're confused by the MC4 extension cables. If you've never worked with solar modules before, they can be a little intimidating. First of all, they're expensive. Nobody wants to purchase an expensive cable and later find out the length is too short after it's been cut. Cut cables cannot be returned, so we want to be sure you fully understand how to choose the appropriate length and how to use them to connect your panels together.
MC4 is the name of the connection type on all new solar panels, providing an IP67 waterproof and dust proof safe electrical connection. MC4 will not connect with older MC3 type connectors.
The MC4 connectors work best with 4mm solar cable.
When you buy any new solar panel (usually over 50 Watts) it will be already fitted with two 4 sq. mm wire with MC4 connectors attached for you to get the power safely out of the solar panel.
You can buy pre cut wires from 2 Meters to 10 Meters, We sell these, but a more efficient way is to buy the cable which you can cut to the exact length you need and then attach MC4 connectors.
We offer a custom cut length cable with MC4 connectors fitted service, if you do not feel confident enough to tackle this yourself.
All you need is the cable, a male and female MC4 connector, wire strippers, some wire crimps and about 10 minutes of your time.
On to connecting..........
Step 1: MC4 Male Connector Fitting
You will notice the wire is stripped shorter than the metal crimp connector. There is a mark on the metal to indicate how far the other connector will enter into this one, if your cable extends past this mark in the connector you will not be able to join the MC4 connectors together.
Recommended cable stripping length is approx 1 inch.
On to crimping...............
Step 2: Crimp the Cable
We are using a MC4 4 mm crimp connector or Pilash for this because it gives a great connection every time and holds all the bits in place when you crimp.
Step 3: Nut on First
Pass the screw nut over the metal crimp first
The plastic housing has a non return clip inside and if you have not put the nut on the cable first you will not be able to get the plastic housing off without damaging it rendering it unsafe to use.
On to inserting the cable...................
Step 4: Insert the Cable
When you push the crimped cable into the connector, you will hear a "CLICK". This is the non return clip locking the crimp into the plastic housing.
On to checking the rubber washer...................
Step 5: Rubber Washer
Looking closely at the picture you will see that the rubber seal washer is flush with the end of the plastic fingers around the cable.
This will give the best grip on 4mm cable when the nut is tightened onto the plastic housing.
If you do not do this with 4mm cable the connector will be able to spin around the cable and over time may damage the connection.
On to the female connector......
Step 6: Female Crimp
We put a little bend in the cable for better surface contact inside the crimp. This cable insulation is stripped by 15mm to expose the wire for crimping.
Crimp the same as the male in step 2.
On to inserting the cable.................
Step 7: Insert the Cable
Again pass the screw nut over the cable first ( step 3 )
Check the rubber washer as in step 5
Then push the crimped cable into the female housing until you hear the "CLICK"
Tighten the nut onto the female plastic housing.
Step 8: Test Before Connecting
We would advise you to test the continuity of your cable with the new MC4 connectors on before connecting to your solar panels or charge controller.
This will confirm you have a good connection that will last for years.
Please remember never disconnect the connectors when the sun is on your solar panels or they are connected to a battery, you may be injured by your free green electricity. Now, you can buy MC4 connectors ( 1 Wire In - 1 Wire Out, 2 Wires In - 1 Wire Out, 3 Wires In - 1 Wire Out and 4 Wires In - 1 Wire Out) from Loom Solar store. We assure home delivery within 3 days at your place. Stay safe and thank you for looking at our MC4 connection guide.