Failure of mc4 connectors

mike_s

softdown said:

MC4 copies? I have not seen anything but MC4 connectors used for the past 1/2 dozen years or more.

Search for MC4 on eBay and Amazon. There are lots of obvious copies. Here's one where it's extremely easy to see. Heck, click between the "1 pair" and "5 pair" choices and you'll see they're selling two completely different MC4 copies (neither is a real MC4).

mcgivor

Copies are probably more common than the genuine article, which promoted this discussion in the first place, the potential problems of mismatched components. I'm sure the panel manufacturers would use this to their advantage regarding a warranty claim, but personally in my location, a warranty is a bumper sticker, when they can't see it, its expired, thankfully in the western world one has specific rights to protect the consumer, in this case don't cut off the connectors before perusing a warranty claim, in my case cut them off and find a better solution, because you're on your own anyways.  

softdown

mike_s said:

softdown said:

MC4 copies? I have not seen anything but MC4 connectors used for the past 1/2 dozen years or more.

Search for MC4 on eBay and Amazon. There are lots of obvious copies. Here's one where it's extremely easy to see. Heck, click between the "1 pair" and "5 pair" choices and you'll see they're selling two completely different MC4 copies (neither is a real MC4).

Interesting history on the origin of the MC4 name (Multi-Contact 4mm). I strongly suspect that the crimps made by the installer will determine how well most of the connectors hold up.

I've worked with many contractors that liked to blame problems on the manufacturer. I'll bet most of us will agree that it is *usually* the contractor.

Photowhit

softdown said:

MC4 copies? I have not seen anything but MC4 connectors used for the past 1/2 dozen years or more.

Most of what you would buy cheaply, are imported from China and are copies. I've even seen ones designed for soldering!

That said, I've bough the cheap ones and never had a problem... Even checked out the first bunch and they seemed to have a water tight seal...

I did think the MC/Staubi had licensed the design to others... might just be bad recall from my faulty mind...lol.

mcgivor

This is one of the failed connectors, found 3 with the same problem, all female notice even the gland nut is cracked, nothing was forced, just plugged together, no major resistance, about 3 years old.

littleharbor2

Whoa!  If that's not physical damage It's likely whatever they used for the body isn't up to being in the elements.

BB.

Yea, it looks like bad quality or wrong plastic. I searched for what type connector Schutten used, and I cannot find anything that says that they use MC4 connectors, just "Locking connector working compatible worldwide"

It does not look like MC4, but perhaps the fragments in your photo have obscured the actual MC4 profile.

https://en.wikipedia.org/wiki/MC4_connector

-Bill

mcgivor

The connectors  were not from the Schutten panels themselves but rather the aftermarket pigtails, used to marry the panels into the system, connected to the panels, all the Schutten connectors are intact, just the aftermarket female connectors failed.

Solray

The plastic looks too glossy. Probably too hard and brittle. Whether that is how it was made or if it is UV damage is the question. Do you have any spares that were stored out of the light? If so, compare the shear strength and flexibility of each.

mcgivor

All the female pigtail connectors are either broken or have hairline cracks, today I noticed the current acting erratic, so went out to investigate, the last one still in circuit was hot, there was a measured 1.5A loss across it, probably more intermittently, will be removed tomorrow morning. The name on the connector is How Full Star, screams out Chinese, avoid using these fake, copy, high resistance pieces of garbage at all cost.

Estragon

Probably made at night off the books at the NumberOneBestHowFullStar plastic toy factory

littleharbor2

How many of these pigtails are there?. Really isn't a big deal to cut out and crimp new ones provided you have access.

Solray

> @Estragon said:
> Probably made at night off the books at the NumberOneBestHowFullStar plastic toy factory

Lol. Yep probably right next to the line producing i Phones.

solar_dave

OK so failed MC4 seem to be the norm even using proper tool to disconnect.  The removal of the panels here to fix the roof required the replacement of several MC4 connectors (like 6-8 out of 72), one of which was visually OK but was not water tight and caused ground fault at the inverters. That one took some doing to find it, the installers were about ready to start at the end of the string and just replace them all till they found the bad one.

If working on your array be aware of the possibility of replacement MC4 connectors.

Solray

Does anyone put shrink tube over their connectors? It might be a good idea, prevent UV damage and help with water intrusion.
I have never seen one fail myself in 5 or 6 years, but it sounds like there are a lot of poor quality ones floating around out there.

Photowhit

Solray said:

Does anyone put shrink tube over their connectors? It might be a good idea, prevent UV damage and help with water intrusion.
I have never seen one fail myself in 5 or 6 years, but it sounds like there are a lot of poor quality ones floating around out there.

I think most MC4 connectors are out of the sun, behind panels...

...at least mine are, not sure when you would have a design where they would be in direct sunlight. Under panels also give some protection from rain, I intentionally clip mine to the side of the panel under the rim. Just made sense when I was wiring them.

mcgivor

The solution to the low grade connectors was to inline  splice with tinned copper barrel compression fittings, wrapped with 3M self vulcanizing rubber splicing tape, followed by 3M Temflex insulation tape, production wise, its the highest it's ever been, 1340W from the 1500W array. So in hindsight the bogus MC4 connectors were probably wasting energy due due to high resistance, was lucky to see 1000W, prior to their elimination.

Estragon

> @Photowhit said:
>
> I think most MC4 connectors are out of the sun, behind panels...
>
> ...at least mine are, not sure when you would have a design where they would be in direct sunlight. Under panels also give some protection from rain, I intentionally clip mine to the side of the panel under the rim. Just made sense when I was wiring them.

Mine end up getting some morning sun in summer. The array is a bit west of south because of a bit of morning shade and no evening shade, and they're a ~65° angle to shed winter snow. The result is some morning sun hits the back of the panels.

mcmasti

No one seems to address an anomaly I've found.  All the pictures of MC4 connector internals show the metal core pices (male and female) as having two "wings" that are clearly made to be crimped over.  However, the Amphenol MC4 connectors I have bought do not have such wings.  The wire-insertion end is a complete cylinder with very solid walls.  I cannot imagine crimping these;  they look as if they are made for soldering.  Has anyone seen this type of MC4?

softdown

Has anyone come up with a way to wrap MC4s to discourage theft? Wires can be cut but most would prefer to have the factory MC4 connections.

Somebody recently disconnected two of my panels and "failed" to re-connect in serial. May have been evaluating the theft. A few folks know that I regularly leave for at least a full day. One of them gives meat to my dogs when I am not here. 

I did engrave the aluminum frames but some grinding would take care of that. 

littleharbor2

mcmasti said:

No one seems to address an anomaly I've found.  All the pictures of MC4 connector internals show the metal core pices (male and female) as having two "wings" that are clearly made to be crimped over.  However, the Amphenol MC4 connectors I have bought do not have such wings.  The wire-insertion end is a complete cylinder with very solid walls.  I cannot imagine crimping these;  they look as if they are made for soldering.  Has anyone seen this type of MC4?

The Amphenol connectors require a different crimping tool. Or a different set of dies at least, if you can swap dies in your tool.

mcgivor

Photowhit said:

...or just use a dang butt connector....

Since I began this thread I've removed all MC4 connectors, and used butt connectors wrapped in 3M.self vulcanizing splicing tape, never had a problem since, MC4 connectors may be convenient however interference connections are always prone to failure, besides how often do they need to be disconnected? 

solar_dave

I recently had to have all my panels removed to do some roof repair. Lots of the MC4 connectors broke during disassembly. The contractor did replace the busted ones but it was a battle to find all the leaks.  the connections get wet and the inverter stops cold.  All fixed now.

Dave Angelini

This long thread had more detail on the old problem. Too many billable o\hours lost on connectors...
https://forum.solar-electric.com/discussion/354921/hope-for-the-best-plan-for-the-worse

softdown

mcgivor said:

Photowhit said:

...or just use a dang butt connector....

Since I began this thread I've removed all MC4 connectors, and used butt connectors wrapped in 3M.self vulcanizing splicing tape, never had a problem since, MC4 connectors may be convenient however interference connections are always prone to failure, besides how often do they need to be disconnected? 

Too windy to check solar wire thickness on the roof. What size butt connectors? 12-10 I would imagine but want to make sure.

I currently favor the idea of steel connectors wrapped in vulcanizing rubber over the insulated butt connectors that are commonly sold and installed. 

Wheelman55

softdown said:

mcgivor said:

Photowhit said:

...or just use a dang butt connector....

Since I began this thread I've removed all MC4 connectors, and used butt connectors wrapped in 3M.self vulcanizing splicing tape, never had a problem since, MC4 connectors may be convenient however interference connections are always prone to failure, besides how often do they need to be disconnected? 

Too windy to check solar wire thickness on the roof. What size butt connectors? 12-10 I would imagine but want to make sure.

I currently favor the idea of steel connectors wrapped in vulcanizing rubber over the insulated butt connectors that are commonly sold and installed. 

These Butt connectors go down to 8 awg https://ceautoelectricsupply.com/product/mega-butt-connectors/

these butts are 12-10 and smaller https://ceautoelectricsupply.com/product/non-insulated-butt-connectors/

mcgivor

softdown said:

mcgivor said:

Photowhit said:

...or just use a dang butt connector....

Since I began this thread I've removed all MC4 connectors, and used butt connectors wrapped in 3M.self vulcanizing splicing tape, never had a problem since, MC4 connectors may be convenient however interference connections are always prone to failure, besides how often do they need to be disconnected? 

Too windy to check solar wire thickness on the roof. What size butt connectors? 12-10 I would imagine but want to make sure.

I currently favor the idea of steel connectors wrapped in vulcanizing rubber over the insulated butt connectors that are commonly sold and installed. 

What I did was to take a sample of the panel wire to the store and found a butt connector that allowed the conductor to fit with minimal clearance, I believe they are 12 AWG for the 250W panels.