March 15, 20215 yr I recently replaced my inverter due to space constraints slightly moved the inverter, requiring me to extend my 4mm2 PV wires. There was previously no joint required in the wires, and wanting to keep the wires in the conduit, I decided against using MC4 connectors just to extend them by 1 meter. Instead I opted for crimp ferrules which are properly crimped using a crimping tool and wrapped them in insulation tape and then covered that in heatshrink. But I'm questioning now whether this is the proper way to do it. Also, I noticed the ferrules state they are tinned - does this mean they should be soldered instead of crimped? The crimp definitely keeps the wires in the ferrule and tugging on it doesn't pull it out, but the crimp doesn't apply nearly as much pressure on the strands as MC4 crimping tool would. How do you guys extend them?
March 15, 20215 yr Mine were done like you did yours, but in hindsight I'd rather have used a mc4 connector.....Just because I hate electrical tape!
March 15, 20215 yr Author 3 minutes ago, FixAMess said: Mine were done like you did yours, but in hindsight I'd rather have used a mc4 connector.....Just because I hate electrical tape! Did you also just crimp them, or did you use solder?
March 15, 20215 yr Author Just now, FixAMess said: Just crimp.... I'm thinking of sandwiching a little plastic box in the conduit where the current joint is and rather use MC4 connecters inside the box to join them. That said, I'm not sure if MC4 connectors actually have higher loss than crimp ferrules.
March 15, 20215 yr I haven't but if I needed to, I would crimp, then solder and then use heat shrink tubing overlapping the insulation by 4 to 5cm either side of the ferrule.
March 15, 20215 yr Hopefully an Engineer/electrician will provide some decent input. I need to inspect mine to see what state they're in after 12 months usage.
March 15, 20215 yr Much ado about nothing. The correct sized ferrule, using a proper crimp connector - rachet type is best. Then a single shrink sleeve with 20mm excess on each side of the crimp is more than enough.
March 15, 20215 yr Author 6 minutes ago, Adri said: Much ado about nothing. The correct sized ferrule, using a proper crimp connector - rachet type is best. Then a single shrink sleeve with 20mm excess on each side of the crimp is more than enough. What I've done is to offset the joints along the cable by a few centimeters. Still properly insulated and heatshrink applied, but now virtually no chance of contact
March 18, 20215 yr One thing to keep in mind is a ferrule joint should rather be done inside an accessible junction box for future inspection or fault finding and not in a conduit where it cannot be seen or inspected. I prefer ferrules tightly crimped, taped up and heat shrinked for extra protection, it should be sufficient for years to come. Soldering is not recommended for ferrules as it will change the integrity of the ferrule to conductor it can become loose or even form cracks with time. When using MC4 connectors make sure you use the same brand male to female connectors because the different brands are not 100% compatible and can cause loose connections.
March 20, 20215 yr I understand that MC4 connectors are designed and made for outdoor use. They don't make sense indoor. The installer of my PV panels used the factory fitted ones only for interconnecting the panels in series. On the feeder ends he cut them off and spliced the extension wire with insulated crimp ferrules in such a way to them that the splices got inside the roof.
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