147 volts dc will not pass thru breaker (yes, breaker is on)

[ksmithaz1]

Lubricant and rubber compatibility (something all guys should be familiar with). There are many different materials.

I would be concerned WD-40 might dissolve seals.

I have a particular grease for use with seals on pool pump.

Silicone lubricants are also only for some seal materials. I was reviewing a recommendation for field maintenance, when the factory material wasn't readily available. Because the program had assigned its own part numbers, was more difficult to track down manufacturer data. But turned out to be a silicone lube being considered, and the device had silicone O-rings. Those were NOT compatible.

Scowl, yea, generally in my experience silicone lubricants are better for most cheap o-rings, but I find it interesting that a silicone based lubricant would not be suitable for a silicone O-ring. Plastics on cars are generally fairly tolerant of most oils, but the problem with alcohol based fuels comes to mind. A lot of the automotive seals around connectors went to an orange waffle stuff a while back. I'm guessing the chinese built MC-4 is not using anything esoteric, probably ABS with an off-the-shelf silicone o-ring. Maybe we should try KY Jelly?

 

[ksmithaz1]

My father owned a swimming pool company. We always used Vaseline on all the housing buckets and such. Been a long time, but I think we used it for the impeller shafts and the like as well. For some reasons customers didn't like to see black lithium grease all over everything at their pool.

 

[PVorBust]

I find it interesting that a silicone based lubricant would not be suitable for a silicone O-ring.

Same with sex toys - never use silicon lube on silicon rubber.

black o-rings are likely to be a nitrile rubber, while orange are probably a fluro-elasomer

Vaseline will destroy latex, but is ok on silicone.

You need to know your "rubber" before you pick your lube.

 

[Hedges]

That's what I said!

Lubricant and rubber compatibility (something all guys should be familiar with).

;^)

 

[Hedges]

(Did I say I bring to bear my experience from a wide range of disciplines?
I'm a "multi-disciplinary" engineer.)

 

[ksmithaz1]

Same with sex toys - never use silicon lube on silicon rubber.

black o-rings are likely to be a nitrile rubber, while orange are probably a fluro-elasomer

Vaseline will destroy latex, but is ok on silicone.

You need to know your "rubber" before you pick your lube.

Got it KY Jelly for, ...

 

[Whats_per_question]

I'm dying to see how this not having to disassemble them to to put the ends on for crimping works.

Lets use this video here so you can tell us what he did wrong when he "took it apart" to crimp the end. I know that most of the mc4 end will fight you tooth and nail shoving that end into it without unscrewing the part off the mc4 connector. I also know its a heck of allot easier to get the holder onto the cable before you crimp the end on it.

Hi @Crowz
There is a chance that the brand he used recommends disassembling the 'nut' end of the MC4, but i doubt that very much.
The correct way (according to every MC4 supplier i've ever used) is to crimp the metal part like he did, then simply push the metal part into the MC4 until you hear and feel the click, then pull back to ensure it has engaged. This is what the barbs are for - to allow the metal part to be inserted but not pulled out. If the correct way to fit was to disassemble, the barbs would instead be collars, and there would be a greater difference between the diameter of the metal connector part and the outer diameter of the collar.

I saw another user comment that "it probably doesn't hurt" - i disagree. There is a very real chance that you pinch the seal when trying to re-fit the back end of the MC4, leading to leakage, corrosion, and a failed connector, possibly a fire.

I don't know why anyone would argue against using the manufacturer's instructions just because "that's how i was taught" or "that's what i saw on the web" or any other reason?
Why would you risk a declined insurance claim when the correct installation method is faster, more reliable, and you don't risk dropping the 'nut' part or losing the sealing gland?

 

[PVorBust]

and you don't risk dropping the 'nut' part or losing the sealing gland?

I believe that is the key to the design - the less parts the installer has to juggle while trying not to fall off a roof, the better the chance the connector is assembled complete and correctly (it also removes the temptation to use a shell after loosing the gland).

 

[12VoltInstalls]

don't think there's any harm in disassembly, just wasted time

I had an issue with water ingress due to freeze/thaw where it would suck in the rubber compression ferrule that is supposed to be IP68 (or 67?) iirc
Took me a couple months to figure it out.
I replaced every MC4 with new ones but I squirted lexel inside before sliding the compression rubber into place. Then lexel’d over that before tightening the nut. Been a coupla years and no further problems. “Disassembly” takes seconds and I can guarantee no leaks. Never had the orings leak.

Lubricant and rubber compatibility (something all guys should be familiar with). There are many different materials

I’ve grown an affinity for the overpriced CRC dielectric. Vaseline crumbles over time as does cheap dielectric in my observations.
From the feel it is a silicone grease. Though I haven’t seen problems I have wondered about compatibility with the MC4 orings.

Do you have comments on this product?

 

[Hedges]

https://www.crcindustries.com/media/msdsen/msds_en-1003734.pdf

Polydimethylsiloxane - Wikipedia

en.wikipedia.org

I suppose the silica is to make it less runny.

"silicone polymer" so need to ensure O-rings are compatible with that.

 

[12VoltInstalls]

"silicone polymer" so need to ensure O-rings are compatible with that

So far so good ?

 

[Whats_per_question]

So far so good ?

Connector location is important too - the MC4's should be fine in all weather, but i prefer to help the MC4 out (and also make for a tidy installation) by using stainless cable clips to keep the cables hidden under the panel frame, out of the sun and rain.

In NZ, the regs say that on a roof, the cable can't touch the roof (as this would impede the flow of leaves washing down the roof, or abrade the cable over time if there was any rubbing) and can't be unsupported for >300mm. Also, some panels are delivered with ~750mm leads, others with ~300mm leads, so if you are not interleaving the panels, you will have about 3 loops of cable to support.

Does everyone interleave these days?