MC4 connectors a massive scandal

[JRH]

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It's listed for 600 volts. It's jacket is rated for 600 volts. It's a piece of metal that is crushed onto other pieces of metal. As long as there is a solid link between the two ends of wire and the connector, what does the voltage have to do with it? It's not a switch or breaker, it does not have to safely extinguish an arc.

I would think the main concern is what kind of amperage it can handle.. but it's designed for 10awg, so I would assume it can handle the same amperage that 10awg would.

The Wirefly connections are rated at 600 volt ..and the standard current rate as marine wire for their
12 - 10 - 8 awg connecters ,( depending on which you use…)
I use them on all 12 and 10 ga connections or smaller ……..on 8 Gauge I may use them or a regular copper lug depending on the use…everything above 8 ga is generally a lug of some type , again depending on use.

J.

 

[cs1234]

Its not against uv .
And that is a problem if sunlight will damage the outside.
Those things are use for inside .

UV is a valid concern. Thank you for bringing it up.

Ideally it would be underneath a solar panel, in the shade. You could wrap it in some UV rated tape or heat shrink if concerned about ambient light bouncing off another surface. Or have the splice in a piece of UV rated conduit. You would need to consider how whatever you do to UV proof it affects it heat wise.

 

[Suijkerbuijk]

I do understand why people look for alternative connection.
Not all people can walk on the roof top see if its still oke.
I forget that i can always see my panels and connections .
So if somtings is wrong i see it directly.

But go always for safety and good Connector have a certificate for it
Than you do not have insurance problems.
People who do not have insurance.
The problem you have is that the house next to you burn with your house .
You are responsible that thare house is burn down.

Just be save .

 

[Ron-ski]

I do wonder about the MC4 connectors that are installed in the rain, they must get water in them.


@Boron nice to see another forum member in SE Kent.

 

[Hedges]

I do understand why people look for alternative connection.
Not all people can walk on the roof top see if its still oke.
I forget that i can always see my panels and connections .
So if somtings is wrong i see it directly.

But go always for safety and good Connector have a certificate for it
Than you do not have insurance problems.
People who do not have insurance.
The problem you have is that the house next to you burn with your house .
You are responsible that thare house is burn down.

Just be save .

Because these connectors (or look-alikes used in massive quantity across the world) are infamous for causing fires.
Walmart, after several fires from SolarCity installations, shut off their remaining PV systems. Yet several more caught fire.

We've since learned (or now specified) that only same brand connectors or pairs tested for UL listing together can be mated.
I don't know if anyone reports problems with genuine Stabuli, but that is my plan going forward.

Equipment that is UL Listed isn't perfect. Just Forgiven.

 

[ThaiTaffy]

I do wonder about the MC4 connectors that are installed in the rain, they must get water in them.


@Boron nice to see another forum member in SE Kent.

Do you have much choice living in the UK?

 

[ThaiTaffy]

Because these connectors (or look-alikes used in massive quantity across the world) are infamous for causing fires.
Walmart, after several fires from SolarCity installations, shut off their remaining PV systems. Yet several more caught fire.

We've since learned (or now specified) that only same brand connectors or pairs tested for UL listing together can be mated.
I don't know if anyone reports problems with genuine Stabuli, but that is my plan going forward.

Equipment that is UL Listed isn't perfect. Just Forgiven.

As I said earlier I'll be going with molex more than likely too many stabuli copies here for me to trust them.

 

[Mattb4]

Because these connectors (or look-alikes used in massive quantity across the world) are infamous for causing fires.
Walmart, after several fires from SolarCity installations, shut off their remaining PV systems. Yet several more caught fire.

We've since learned (or now specified) that only same brand connectors or pairs tested for UL listing together can be mated.
I don't know if anyone reports problems with genuine Stabuli, but that is my plan going forward.

Equipment that is UL Listed isn't perfect. Just Forgiven.

Speaking of Stabuli. I just used them in my MC4 replacement drive. I have to admit I am not favorably impressed with them considering how much they cost. The gland nuts on them with the packing they have does not fit properly for 12-10awg PV wire (I am using Temco PV wire) and the nut has a bad tendency to cross thread if not careful.

Time will tell considering how weather proof they are.

 

[Boron]

I would probably put a second shrink sleeve over those if I was going to run near 600 volts DC. They are truly watertight. I have them submerged in the bilge of my boat to power the bilge pumps.

Life is too short to use bad connectors.

Holy Schwepps Batman
Blatant commercial dishonesty here (not @Dave911 ) On this board it has been noted that a lot of crimp connection types can fail from various Cheap Charlie source which we a flooded so deeply we can hardly recognise genuine matters. Crimping successfuly (eg to Mil spec stds) is a very scientific matter not just a quick squeeze as you do with your OH. It needs a precision butt splice ferrule (precise dims, mtl and thickness) and a proper crimp tool with precision anvils to match the ferrule. Large ferrules of the right internal diameter as needed for Solar 10 AWG need a hydraulic tool to get 10+tonnes force for metal cold welding - the essence of a proper crimp. A professional kit, tool plus range of ferrules may cost ca $500 to set you up.

Those PRC marine butt crimps are steel from PRC and no Ampacity rating quoted just wild claims of high voltages (are these really UL tested?) and NOTICE the sellers dont offer you the tool to do the crimp ( does this seem strange? Are you suspicious at this glaring omission. I surely am livid at this dishonesty).

However - what ever floats your boat - YMMV

BTW I am testing an alternative old school method just now - watch this space guys - will propose for your usage ( ca $1 ea no commercial interests or clickbait involved BTW)

 

[Dave911]

Holy Schwepps Batman
Blatant commercial dishonesty here (not @Dave911 ) On this board it has been noted that a lot of crimp connection types can fail from various Cheap Charlie source which we a flooded so deeply we can hardly recognise genuine matters. Crimping successfuly (eg to Mil spec stds) is a very scientific matter not just a quick squeeze as you do with your OH. It needs a precision butt splice ferrule (precise dims, mtl and thickness) and a proper crimp tool with precision anvils to match the ferrule. Large ferrules of the right internal diameter as needed for Solar 10 AWG need a hydraulic tool to get 10+tonnes force for metal cold welding - the essence of a proper crimp. A professional kit, tool plus range of ferrules may cost ca $500 to set you up.

Those PRC marine butt crimps are steel from PRC and no Ampacity rating quoted just wild claims of high voltages (are these really UL tested?) and NOTICE the sellers dont offer you the tool to do the crimp ( does this seem strange? Are you suspicious at this glaring omission. I surely am livid at this dishonesty).

However - what ever floats your boat - YMMV

BTW I am testing an alternative old school method just now - watch this space guys - will propose for your usage ( ca $1 ea no commercial interests or clickbait involved BTW)

Hi Boron,

I'm confused as to what you are saying. Who is being dishonest? (I appreciate you saying its not me!)
I do electrical work, actually more engineering and programming than wiring. But I still routinely do work on 480 VAC gear, including work on it while hot.

Although not obvious, 480 volts RMS peaks at about 680 volts actual. Many of the circuits I work on routinely run at 540 volts RMS, which pushes the peak voltage way past 700 volts. This is on routine power wiring for motors and drives, etc.

Plain old Yellow 10 gauge crimp sleeves are routinely used on these voltages in industry. Nothing unusual at all. They are also used outside, but they are used in conduit boxes. Wire nuts are used the same way. I don't make the rules. People do what they want and they typically don't ask me.

The marine grade butt connectors do vary in quality and its never a good idea to leave wiring exposed to direct UV, but THWN type wire does last for a long time exposed to the sun. I would try and hide any exposed wiring behind the panels. Personally I will likely use wire loom or short conduit sections to hide my roof wiring from direct UV. I think a yearly visual inspection is also a very good idea.

You would be surprised at the actual insulation withstand voltage of wire and connectors. Its way beyond their ratings.
Working in a wire plant, they routinely test the 600 volt rated THHN type wire (Nylon over a PVC jacket) at over 10,000 volts DC as the wire is being made. I have seen miles of wire zip through the tester with no faults (they log them).

I wouldn't have a problem working with 1500 volts DC if all of the components were properly rated and of a reputable brand.

 

[Hedges]

Although not obvious, 480 volts RMS peaks at about 680 volts actual. Many of the circuits I work on routinely run at 540 volts RMS, which pushes the peak voltage way past 700 volts. This is on routine power wiring for motors and drives, etc.

480Vrms Line to Line, not Line to Neutral (or ground). Unless that is corner-grounded delta.

277Vrms nominal is what the insulation sees.

 

[Boron]

Hi Boron,

I'm confused as to what you are saying. Who is being dishonest?

Sellers, marketing mongrels, of course. Naïve buyers are not given the whole picture and sent off thinking they just make any old squeeze with some leccie pliers OMG.

 

[Dave911]

480Vrms Line to Line, not Line to Neutral (or ground). Unless that is corner-grounded delta.

277Vrms nominal is what the insulation sees.

At best. If one 480 volt line crosses an open terminal of another phase, you have full voltage across one layer of insulation.
I have seen this many times in sloppy control panels. Some are that bad.
If a 480 volt Delta secondary transformer has a fault to ground. The two other phases are now 480 volts above ground. I have seen that. Even worse when the fault is arcing to ground periodically. Crazy things will happen. All three phases will leap way above ground. Ungrounded Deltas are very bad. They used to be very common at GM auto plants. You could have a line to ground fault and still run the plant!
Sooner or later they might fix it. Or maybe not.

 

[Hedges]

Sunny TriPower manual warned me about delta getting a corner ground fault. Probably EMI caps to chassis.
I bought a zig-zag transformer to go with the 480D to 120/208Y I planned to drive backwards (step-up with it didn't go well.)
I've now repurposed a multi-tap delta to Y as Y auto-transformer.

I'm about to put a Wattnode power meter inside surge arrestor box (convenient enclosure near service entrance). That will have wires from 120/240V that pass by lugs of opposite phase, similar to your 480V terminals.

Good point.

 

[Ron-ski]

Do you have much choice living in the UK?

Not at the moment, we're 9 days into July, and some areas have already had more than a month's worth of rain.

 

[Suijkerbuijk]

Not at the moment, we're 9 days into July, and some areas have already had more than a month's worth of rain.

Same here in the Netherlands.
Rain , rain and more rain.
And today more of wind and rain.
We try to use windmolens to push back to the uk

 

[DIYJim]

Millions of commercial solar farm connections are made with quality MC4 connectors. MC4 make testing individual panels easy when troubleshooting and looking for bad panels. My suggestion is buy quality, not cheap kits from Amazon.

 

[Boron]

Millions of commercial solar farm connections are made with quality MC4 connectors. MC4 make testing individual panels easy when troubleshooting and looking for bad panels. My suggestion is buy quality, not cheap kits from Amazon.

I would be most interested to know what the commercial practice is for testing Solar panels in situ. You can test current output with a hall clamp meter, no need to break the cct for example. You can scan the surface with an IR camera? Whats the inspection protocol on a solar farm with thousands of panels? As an ex Eng Mgr I would need a paper trail system to organise labour. In the West field tech labour needs special training, is scarce and expensive (as a young friend of mine showed me briefly). A log of failure events must be kept. Annual maintenance shutdowns arranged and so on. How is it all done in the Solar Farm business?

 

[Boron]

Same here in the Netherlands.
Rain , rain and more rain.
And today more of wind and rain.
We try to use windmolens to push back to the uk

Holland home of dykes (not the diesel kind) and windmills. Do you know what power was generated by large field windmills? Below is a pic of a wooden flour mill that I would have seen ca 1935 from my house ca 500m distant. We had twenty in the area at one time. They were costly to maintain and keep running (especially the stones and sails) so were all demolished before 1939. We still have a number of working pumping mills draining the Fens (Norfolk)

 

[BarracudaBob]

Guys these are the standard "Lucas" pattern push fit connectors widely used in the auto industry for decades. However beware Chep Charlie, he makes these out of thinner metal so they dont maintain the spring force between blade and female socket.. Check your self to see the difference.
In principle these are very good but only go to 20A (6.3mm blade). However there is a 9.5mm blade version (yellow) but you can only get it in FEMALE. The industry only expected these to be used on equipment ie connecting a dynamo. Good for 40A maybe. I have a collection of these Ebay). Sorry not allow to mention here. I use the uninsulated crimp pair versions together with crimp/solder (at core tip - dont let it wick down the cable) then apply glue heatshrink. a silicon tube shroud can be fitted over the coupling with si grease. Pulls apart easily for occasional maintainance. Its old school and you can inspect it - unlike rubbish MC4s

But thats my 10c YMMV

Where do we buy the good ones?

 

[OpenNRG]

Temco Silver Plated Copper

https://www.ebay.com/itm/282347691154?var=581460679228

 

[ThaiTaffy]

Where do we buy the good ones?

RSOnline have always been my source when needing to buy 100% original components

 

[Hedges]

I would be most interested to know what the commercial practice is for testing Solar panels in situ. You can test current output with a hall clamp meter, no need to break the cct for example. You can scan the surface with an IR camera? Whats the inspection protocol on a solar farm with thousands of panels? As an ex Eng Mgr I would need a paper trail system to organise labour. In the West field tech labour needs special training, is scarce and expensive (as a young friend of mine showed me briefly). A log of failure events must be kept. Annual maintenance shutdowns arranged and so on. How is it all done in the Solar Farm business?

I think IR camera while operating could be the best.
I could see varying levels of defects in my Sharp array that had some bad ones.

There are non-contact volt meters, not sure if AC only. There are non-contact AC/DC voltage testers.

 

[robbob2112]

Poking around trying to order some genuine Staubliu connectors and find the right specs for the PN I need to match my panels. Took a while to find the information - uploaded them here

Staubli MC connector specs

PDF from this page - https://www.staubli.com/us/en/electrical-connectors/products/renewable-energy-solutions/cable-coupler.html I was trying to find information to order specific MC4 connectors and it was painful to find so I figured others...

diysolarforum.com

 

[HRTKD]

I've had the TEMCo Industrial MC4 connectors on my system for four years now. I used TEMCo PV wire too, but that's not necessarily relevant. The solar panels came with Staubili MC4 connectors per the brochure from the manufacturer. I did not cut them off. I mated the TEMCo MC4 to the OEM solar panel MC4 connectors.

The only problem I had was the learning curve for making the MC4 connections and using the right parts on each end. Using a crimper die that is specifically designed for MC4 is critical in my opinion. I'm using the Lunar Series die from Eclipse Tools.