Connecting different brands of MC4 together

[BruceB]

I noticed in the PV Guide this morning:

"2.1.7 d.c. Plug and Socket Connectors
PV specific plug and socket connectors are commonly fitted to module cables by the manufacturer.
Such connectors provide a secure, durable and effective electrical contact. They also simplify and
increase the safety of installation works.
Plugs and socket connectors mated together in a PV system shall be of the same type from the same
manufacturer and shall comply with the requirements of BS EN 50521. Different brands may only be
interconnected where a test report has been provided confirming compatibility of the two types to
the requirements of BS EN 50521."

So when I connect a solar edge mc4 to a panel mc4 I need a test report?
And when I connect the last panel or optimiser in a string via an mc4 to a cable going back to the inverter where I have put a mc4 plug on the cable myself then it should be the same manufacturer's mc4 or I need a test report?

I suppose I could cut the mc4 off the last panel in a string and crimp on a new one so that it makes a matched pair with the incoming solar cable. (is there an icon for tongue in cheek?)

Do the consequences of all these rules get thought through!?

 

[Gavin A]

I've always worked on the basis of if the manufacturer states they're MC4 compatible then we should be covered to pair up with MC4s, and tbh I'll stick with that approach as any other approach is unworkable - can't cut the ends off as it will breach manufacturers warranty apparently.

 

[BruceB]

Exactly.
Perhaps another thing to argue about with a pedantic assessor.

 

[SibertSolar]

Most MC4-compatible connectors will not necessarily be compatible with other MC4-compatible connectors. However, most MC4-compatible connectors will be compatible the Multi-Contact OEM MC4 connector. Our versions are tested by TUV to be compatible with the MC OEM product but we wouldn't necessarily recommend using them with any other alternative type.

Cutting connectors off a panel can often compromise a panel manufacturer's warranty, which is why I have a "no objection" statement from Vikram should anyone need to do this to the panels at the end of a string of their modules....

I never noticed this specific wording in the PV Guide though....could be another can 'o' worms......

 

[Worcester]

We noticed that a few weeks ago when I had one of my sparks go through the guide for his own benefit. - At our recent annual inspection it wasn't mentioned.
As SibertSolar says, it is completely impractical as you shouldn't cut off the panel connector.

There is a problem here tough as MC4's are ONLY manufactured by Multi-Contact

from their own website:

Compatibility of PV-Connectors
Multi-Contact clearly dissociates itself from connections made with MC connectors and connectors from other manufacturers due to the high demands placed on safety and reliability of PV installations. Connectors that have not been produced by MC but appear mateable with MC components, and sometimes are being advertised as “compatible with MC” by the manufacturers do not meet the requirements for safe, stable electrical connections and must not be mated with MC connectors for safety reasons. Multi-Contact does not take any responsibility for damages that result from such connections which have not been approved by MC.
Loss of certification
The MC4 connectors made by Multi-Contact are TÜV certified only in combination with connectors from the MC4 product range. Any other connections are not TÜV recognized. When other manufacturers advertise a TÜV certified connection of their connectors with MC products, this does not refer to the connection as such. Only partial tests have been made in such cases.
Technical risks and long-term performance
No long-term experience is available with cross-mating from the field. Experts question the forecast capability of short-term tests and accelerated aging tests with regard to the quality of a connection over a time span of 25 years or more. PV connectors are safety components which contribute to the operational safety (both personal and functional) of the installation. When connectors of different make are mated, this aspect is not guaranteed. Contact elements and insulation elements must be perfectly matched to the last detail. Over a long period of time this may only be ensured by continuous in-process tests which are run inhouse by the manufacturer. Multi-Contact has been on the market with PV connector systems for over 15 years, looking back on according experience from both research and development as well as long-term performance of missions of connections. Simultaneously, characteristics of the connections are being recorded in test fields, proving a good long-term behaviour. For cross-mated connections this certainty is no longer given.

The challenge comes here that MC have clearly made no attempt to protect any rights/branding/design or anything at all about its MC4 connector, and it's actually worse than that as I am sure that they will have entered into oem licenses with some of the suppliers to panel manufacturers, and your chances of finding out who they are is somewhat worse than slim.

In our case we only ever use one brand of MC4 connectors on a site, so the only time this would come into question is at the final connection onto the panel. and the only way to ensure that is to insist panel manufacturers bundle spare mc4's in each pallet. Though even that may not be enough as during install we have noticed differences in MC4's even from the same panel manufacturer.

Is this a storm in a teacup? And is it enforceable?
I can understand the potential issues over safety, however I don't see how it can possibly be enforced.

 

[SibertSolar]

It can't be enforced, and has been a bee in MC's bonnet for as long as I remember. I'll provide a bit more feedback later but I can go back about 10yrs when MC started to aggressively enforce their position but, frankly, it's a minefield as there are few panel manufacturers who actually use MC OEM product nowadays and the guys left in the dark somewhat are the installers....I have a personal experience in this area as I worked 7yrs for a cable-assembly/junction box manufacturer....