MC4 connectors Cross Threading

[jtwigg]

I am trying to get our mc4 connectors installed on my site here in Arkansas. When trying to reach the required torque value of 3.5nm on the nut of the mc4 I am experiencing major cross threading of that nut. My concern with this is that the seal is not getting compress all the way around my cable to make the water tight seal. I am hoping to find out if this is a problem throughout the industry or is this just here because the temperature are so high. I am being told by Staubli that we have to keep the connectors cold to be able to install them properly without cross threading. I am still having issues with them cross threading as long as the temperatures are over a 100 degrees even keeping them in a cooler of ice. If anyone could offer some insight on this it would be greatly appreciated.

 

[Zapper77]

I am trying to get our mc4 connectors installed on my site here in Arkansas. When trying to reach the required torque value of 3.5nm on the nut of the mc4 I am experiencing major cross threading of that nut. My concern with this is that the seal is not getting compress all the way around my cable to make the water tight seal. I am hoping to find out if this is a problem throughout the industry or is this just here because the temperature are so high. I am being told by Staubli that we have to keep the connectors cold to be able to install them properly without cross threading. I am still having issues with them cross threading as long as the temperatures are over a 100 degrees even keeping them in a cooler of ice. If anyone could offer some insight on this it would be greatly appreciated.

Buy new connectors. Sounds like the old ones are garbage.

 

[Ampster]

I make sure the gasket is firmly seated before I attempt to screw on the cap. When I push in the donut shaped gasket it makes more thread available so when it tries to compress the gasket there are enough threads to apply pressure to the gasket and seal around the cable.

 

[Zapper77]

Photo or short video would help. Maybe the masses can help identify the problem.

 

[Tomthumb62]

Edit to say that some veteran plumbers around here will tighten new connections only enough that they drip slightly. They let the minerals in the hard water build up for a couple of weeks. The minerals will usually create a seal of their own. Any connections still dripping slowly after two weeks get another 1/4 turn of the wrench. Over tightened plumbing connections can warp the fittings and cause much worse irreparable leaks. Well only repairable by cutting out the warped fittings and splicing in new ones, which isn’t so easy with rigid pipes. Not entirely applicable to mc4 connectors, but something to consider.

***ORIGINAL COMMENT:
This is why many seasoned mechanics don’t use torque wrenches.

Now I’m not such one and do own a torque wrench. But I rarely use it.

I recently made my first mc4 cables. I used inexpensive BougeRV mc4 connectors. Temps were about 70F when I made them, so there’s that. But I didn’t use a torque wrench. I simply tightened them down with the included tools, which would slip once the nut wouldn’t tighten anymore without what felt like too much force.

Torque wrenches need to be calibrated. They can easily get out of whack and provide too much or little torque. But in this case, tightening until “good and snug” has served me well so far.

 

[400bird]

My Staubli connectors came already threaded together. Just crimp the terminal on the wire, insert into the connector and tighten down the nut/sealing ring. It's harder to cross thread it this way.

 

[RDuke]

Resurrecting an old thread because I have the exact same issue so I thought I would post some pictures. I bought a pre-made cable from Sig Solar, and some MC4 connectors from the same place. They appear to be the same part, but I am having some issues. As described earlier, when I try to tighten up the connector, it only goes so far before the threads start to slip and the cap turns slightly sideways. You can hear it click each time the treads slip. The first picture shows my new connector and the one that came pre-terminated on the cable. You can see that when the cap is just snugged up, theirs is much further onto the threads than the one I made up. The thing is, the gray colored rubber seal is so stiff, there is no way it is going to compress that I can tell. Also, I cannot get that part to slide in any more than just being flush with the mating part. What am I doing wrong? Of all the things to get hung up on. I am concerned about water intrusion. The one I am trying to terminate is the one of the left. The right one was factory supplied on the cable that is attached. Thoughts? I need to figure this out. Please help.