Another MC4 Question by Noobie,

[noy897]

I'm learning more about MC4 connector mismatches. I have BOUGERV connectors from Amazon and am using them to extend my solar panels to reach the junction box. For example, I have the positive side of a panel that needs to reach the junction box, so I grab a 10 AWG solar cable and use a negative MC4 connector to extend the positive connection of the solar panel. At the junction box, I then convert that to THHN wire.

I've been hearing negative stories about MC4 mismatches and am unsure of the correct way to do this to prevent a thermal event. I've read about people buying MC4 clips and replacing the OEM MC4 connectors with the ones they purchased just to ensure everything matches. I’d like to know your opinion on this.

I have Canadian Solar 335s panels, but I'm not sure what brand of MC4 connector they are using. To extend the connection, I'm using a generic MC4 connector from BOUGERV, purchased from Amazon. Should I buy Staubli instead, since they are a known manufacturer of the technology? I saw this listing on eBay:

Staubli MC4 Connectors on eBay

Or should I snip the MC4 connector off the OEM and install the generic one from Amazon so they match?

 

[zanydroid]

NGL -- kind of some really weird behavior here that would be the opposite of what I would do. Like hard no on the following

Or should I snip the MC4 connector off the OEM and install the generic one from Amazon so they match?

I have BOUGERV connectors from Amazon

Don't buy this kind of stuff from Amazon. Use a proper supply house (like Titan) or their eBay store (usually under some weird name). The only things I used from Amazon were MC4 wrenches and crimps. All electrical components were from places like Titan, Renvu, CED. I made my own MC4 extensions using PV cable and my own crimping

Canadian Solar is going to be a proper connector. I believe they are a bankable tier, code compliant brand too. Post a picture of it and people can visually identify. These are often also on the spec sheet or encoded in the full length model number of the solar panel.

Spec sheet screenshot of a CS spec sheet



As well, using MC4 as a generic kleenex brand name is not good for mental. The only MC4 are Staubli. Not Staubli -- call them MC4 style / faux MC4. The OEM connectors from bankable/code compliant have their own designations that do not violate Staubli's MC4 trademark, and have manufacturer names. Such as the T4 / H4 / etc. Sometimes, these have cross compatibility with Staubli listed in their official spec sheets (and presumably attested to by a NRTL, so their bacon is on the line if it turns out to not be true). You can choose to take this as safe enough or not.

 

[noy897]

 

[noy897]

are these the correct connectors?

 

[OffGridInTheCity]

I've used a variety of MC4 connectors over the last 6 years. I crimp AND solder the wire but have always used the existing MC4s on the panels. As far as my experience, they are all physically compatible - e.g. MC4 is MC4 plug-play but... someone recently pointed out that one difference is how well the + and - pins make contact is influenced by the smoothness or roughness of the pins - e.g. rough is better.

Here's a pic from the person on another forum to illustrate....

Notice the 1st box has smooth pins = worst case. The second has indented gripping strips - a better connection. The 3rd example has a flare - again, this would make a better connection.

I just wired up my ground array using these - from AMZ - https://www.amazon.com/gp/product/B00A8TRKJW/ref=ppx_yo_dt_b_search_asin_title

notice the fat ones have some indents that will make better contact than a straight smooth pin.

So I would make sure that whatever you buy has at least some kind of indents to make better contact that the smooth ones

 

[noy897]

i cant even see what is currently on the OEM contacts of the Canadian solar. I'm getting to the point i rather just do some sort of weather proof but connectors. I only need to do them for a few panels. I just cant trust the ones i got from amazon after reading about mc4 connectors burning up

 

[OffGridInTheCity]

i cant even see what is currently on the OEM contacts of the Canadian solar. I'm getting to the point i rather just do some sort of weather proof but connectors. I only need to do them for a few panels. I just cant trust the ones i got from amazon after reading about mc4 connectors burning up

If it helps you - I've never had one fail or burn up but remember I crimp and solder. My oldest ones are on my roof and are now in their 7th year with regular 100F+ summer ambient temps.

A poor crimp (without soldering) might be what lead to loose/arcing connection instead of the actual connector being the issue.

 

[zanydroid]

View attachment 236530

Do you have the testing certificate/invoice for your pallet with full part number and electrical test results? For my Jinko pallet I got it.

 

[noy897]

Do you have the testing certificate/invoice for your pallet with full part number and electrical test results? For my Jinko pallet I got it.

no they are used

 

[zanydroid]

Do you have the testing certificate/invoice for your pallet with full part number and electrical test results? For my Jinko pallet I got it.

Maybe the detailed info is on the serial number plate on the solar panels

Sorry I can’t tell what connectors those are. Maybe you can dig up the datasheet for your specific solar panel, then look up the various types they offer, and do some pattern matching.

 

[zanydroid]

I'm getting to the point i rather just do some sort of weather proof but connectors.

This will require you to cover the solar panels for sure, or work in the dark. You can’t de energize solar strings completely without that.

MC4 connectors can be connected/disconnected without exposing live contacts.

 

[noy897]

It looks like they are Canadian solar t4 connectors. https://titanwnc.com/product/connectors/tlian/tlian-t4-pc-1-male-female-connector-set/

 

[zanydroid]

Based on the spec sheet, which says there's an available pre-made jumper cable from T4 to MC4, I don't believe they're listed for direct connection to MC4.

Tlian T4-PC-1 Male/Female Connector Set | OneMonroe Titan

Tlian T4-PC-1 Male/Female Connector Set - Solar Connectors from Canadian Solar

titanwnc.com

If you are connecting to a MLPE or RSD device, those may not have T4, so you have to decide whether you want to recrimp one side, or build/buy jumpers. If you are connecting to a string, just buy the T4 and make a cable

 

[Lprantner]

I'm learning more about MC4 connector mismatches. I have BOUGERV connectors from Amazon and am using them to extend my solar panels to reach the junction box. For example, I have the positive side of a panel that needs to reach the junction box, so I grab a 10 AWG solar cable and use a negative MC4 connector to extend the positive connection of the solar panel. At the junction box, I then convert that to THHN wire.

I've been hearing negative stories about MC4 mismatches and am unsure of the correct way to do this to prevent a thermal event. I've read about people buying MC4 clips and replacing the OEM MC4 connectors with the ones they purchased just to ensure everything matches. I’d like to know your opinion on this.

I have Canadian Solar 335s panels, but I'm not sure what brand of MC4 connector they are using. To extend the connection, I'm using a generic MC4 connector from BOUGERV, purchased from Amazon. Should I buy Staubli instead, since they are a known manufacturer of the technology? I saw this listing on eBay:

Staubli MC4 Connectors on eBay

Or should I snip the MC4 connector off the OEM and install the generic one from Amazon so they match?

All my Canadian Solar MC4's are incompatible with MC4's from Amazon, in my experience. I just use the existing connectors to connect the array in series, then replace the remaining connectors going to the combiner box with new ones from Amazon OR, better still, bare 10awg crimp butt connectors and marine grade shrink tube.

 

[zanydroid]

Don’t buy anything as critical/fire prone as MC4s from Amazon. Why are y’all doing this, when you can mail order from Titan or other distributors.

The eBay shops are OK , provided you confirm on a forum which distributor is backing a particular shop.