Question on making my own MC4 extension cables.

[TomW]

OK, folks. We are installing about 7 KW of panels at our new 90 year old house in the back yard. 2 dozen 310 watt panels on a Unirac ground mount.

I will need a bunch of extension cables to reach the combiner boxes. I got a couple dozen connector pairs, bulk cable, a crimper and an MC4 tool.

My question is about the MC4 tool. It is plastic and under any real torque tightening the gland nut the wrench slips and clicks. I have looked at a lot of videos and pages of instructions. A few mention tightening the gland nut until there is a click. Is this click they mention the wrench slipping or is my wrench set defective? I don't see how the connector gland nut can click there does not seem to be any mechanism to do that?

The MC4 tools:



These connectors seem stupid simple to assemble and I just want to be sure I am doing it right.

Any input appreciated.

Tom

[tecnodave]

TomW,

The click is the jaw of the tool opening a little and letting it slip to the next notch on the MC-4 connector.............


I'm in the same boat, I have a pallet of new 96 cell frameless panels sitting in my drive in prep for a 10 kW. grid tie I'm doing locally for a freind.....Fronious inverter, midnite combiner, infinium 260 watt panels......a bit strange as they are 6" crystal size panels but have 5" crystals in 8X12 config.....close out...got them for $90USD , smoking deal....full 25 year warranty.....and yeah I bought spares as these are a bit non standard.....I make my own cables and prefer solder pot connectors but those are hard to get.....

Dave

[TomW]

TomW,

The click is the jaw of the tool opening a little and letting it slip to the next notch on the MC-4 connector.............


Dave

I suppose that is the sign it is "tight enough"?

These gland nuts and rubber seals fit very tight even before I screw in the nut much.


Most of my solar installs were before MC-3 and MC-4 were commonly used. Split bolts and lots of 3M "Super 33" tape and NO-OX goop. I gotta say these MC-4 connectors must do a much better long term job.

Appreciate the feedback.

Tom

[tecnodave]

TomW,

They do fit tight, the lock nut is not really required but mc-4 is an "safety upgrade" for the non locking mc-3 type connector formerly used.

Dave

[CDN-VT]

Every cable size has a different feeling and the tools will act as the cable your using . I have Titan  Wire & cable as well NY supplier of PV . I would buy many more terminals in male & female ends as if the crimp sucks . I have lots & the best crimpers , but still waste a few. SDG is also what I use to make sure.
7mm PV is the semi norm , but heavy use COM2 is 8mm and they have a different seal  ..

VT

[russ_drinkwater]

I solder all my mc4 leads I make when required.
There is a crimping tool, but I like the soldered joint!
The end caps I tighten up by hand as with their design there is little chance of moisture getting in especially if mounted under
the panels or in conjute.