Burnt out, incompatible connectors


It started with the insurance company canceling all coverage for any damages related to plug connectors for modules connected with MC4 plug connectors. The operators wanted a solution that would reinstate insurance coverage, but that was not so easy. In the meantime, there already had been a series of fires. Approximately 2 megawatts of PV plant capacity that went into operation in 2011 is affected. That is the story from the point of view of the operator.

The reason for the termination of the insurance coverage, says the operator, is that the plug connectors are not true Multi-Contact plugs but, according to the module manufacturer, merely a more or less compatible connector. The exact terminology and the agreements between the EPC company and the module manufacturer can no longer be reconstructed, as the former is now insolvent, which makes the case far more complicated. At places where the module cables were not long enough and at the end of strings, the EPC service provider connected the module plug connectors to Multi-Contact plug connectors. Problems are now showing up in these spots.

In the spring, four years after the plant was commissioned, the operators say that all they actually wanted was to purchase the correct plug connectors from the module manufacturer and replace the Multi-Contact plug connectors at the critical locations. However, the module manufacturer could not or would not procure the proper plug connectors. Instead, the company offered an adapter cable which, in the operator’s view, was overpriced.

Interested in discussing the question raised?

Come to our roundtable at SPI in Las Vegas, 12 p.m. to 2 p.m. on September 14.
-> More information

If you have examples of poor quality modules or installations and interesting discussion points – pv magazine would be interested in your story and will treat all submissions with the utmost confidentiality.
-> More information

To register for free, email us at:
-> roundtable@pv-magazine.com

At that point, the operators retained the services of a law firm which advised them that it was in fact a warranty issue. The module manufacturer sees it differently. In its initial response to pv magazine, the manufacturer said that every customer has the option – as had the EPC service provider in 2011 – of purchasing the modules with original Multi-Contact plug connectors. If the purchaser decided against that because the part was slightly more expensive, the customers themselves must take care to ensure that “the string connector is compatible with the purchased module connector.” Furthermore, a statement issued by the law firm of the module manufacturer indicates that warranty claims of the customer – that is, the insolvent EPC company – may not be transferred to the operator.

The manufacturer is not alone in its view that the EPC company bears responsibility in this case. A well-known TDD company writes in response to our published report: “If the module manufacturer writes ‘MC4 compatible’ the service provider has to check to see whether Multi-Contact has approved his plug connector. Otherwise, if a problem crops up, the EPC is on the hook.” Because the EPC is insolvent, it is no longer possible to determine why it opted for the plug connector it deployed. However, the manufacturer is no help in trying to sort the situation out. It will not discuss what promises were made with regard to the module plug connector at the time of sale. In an e-mail exchange with the operator he writes, “There is no approval from either manufacturer, but TÜV Rheinland has confirmed compatibility of the connector system.”

Read also the low quality cases:
-> “Poor quality planning: Shifting the blame, passing the buck
-> “Melting backsheets, broken cells, and hotspots
-> “PID-related performance drop in a solar farm


Further Roundtable material:
-> Interview with George Touloupas, Director of Technology and Quality at CEA
Minor differences in yield percentage make the difference between good and bad investment

TÜV Rheinland explained to pv magazine that, although it carries out sub-aspects of standards on combinations of plug connectors, it has “never issued a confirmation of compatibility” much less a “certificate.” To the contrary, TÜV Rheinland warns against, combining plug connectors from different manufacturers.

The operator is also faced with the problem that he now doesn’t want to purchase the right plug connectors in the open market because the module manufacturer does not want to confirm the compatibility with the connectors on the modules. At the same time, in an e-mail, the manufacturer also informed the operator that it could not supply the plug connectors itself.

Building a Sustainable Future for Large-Scale Solar PV in the U.S.


  • 12 p.m. to 2 p.m. on September 14, 2016 during SPI in Las Vegas
  • Springhill Suites at Las Vegas Convention Center
  • Register at no cost at: roundtable( at )pv-magazine.com
  • Target audience: Asset managers, EPCs, operations & maintenance suppliers (O&M), system designers and independent engineers, financial institutions, insurance companies, investors, system owners (utilities, gencos, IPPs, as well as C & I system owners), certification and testing bodies, research institutes and universities, industry associations, government entities, codes & standards and regulatory agencies.
  • MCs: pv magazine
  • More information
Initiative sponsor partner:Gold sponsor:Gold sponsor:
DuPont logo Clean Energy Association logoMC Logo_height-47
Supported by:Supported by:

This content is protected by copyright and may not be reused. If you want to cooperate with us and would like to reuse some of our content, please contact: editors@pv-magazine.com.