Solar PV systems consist of many components, which are connected by cables and connectors. This is one of the main safety hazards of any solar PV system. In this Solis article we'll share how a connectivity failure could create a security problem and how to prevent it.

Poor Connectivity – A Costly Threat to Your Solar PV System

Article from | Solis Inverters

Solar PV systems consist of many components, which are connected by cables and bespoke connectors.  This is one of the main safety hazards of any solar PV system. In this Solis seminar we'll share how a connectivity failure could create a security problem and how to prevent it.


Connection Failure is one of the Main Safety Hazards of a Solar System

According to actual O&M data from 746 PV plants, the EU Horizon 2020 "Solar Bankability" project team gave a list of the TOP 20 technical failures in PV plants.  "Wrong/Absent Cable Connection" and "Broken/Burnt Connectors", ranked in the top two on the list of failures. 

Figure 1. 



In addition, Fraunhofer ISE research also shows that the root cause of PV system failure is mainly concentrated in poor contact caused by installation problems.

Incorrect or Poor Connection Points

Connection is the general way to form a complete electrical system. In a PV system, there are many connection points. Taking a 30kW three-phase PV system as an example, which uses 100 x 300W modules and a 30kW string inverter; the configuration is as follows

MPPT1: 20 PCS * 2strings

MPPT2: 20 PCS * 2strings

MPPT3: 20 PCS * 1string

The number of DC connection points for a single string is 21 (See Figure 2 below), and there is a total of 105 connection points for 5 PV strings. In addition, there are 24 AC connection points, so overall the system has a total of 129 connection points.

The larger the system, the more connection points. Adding MLPE devices to the original system triples the number of connection points.  In Figure 3 below, only an optimizer is added, and the connection points of the string are increased by 40.



Problems Caused by Connection Failures

In PV systems, improper wiring or incorrect use of cables will result in poor contact and increase in contact resistance.  This affects system performance, increases system costs, can cause additional losses and create hidden system hazards.


How to Connect Correctly

  1. Select correct and high-quality materials, including the selection of DC and AC cables; the selection and configuration of system connectors, circuit breakers, etc. require strict attention in the early design stage.

  2. Ensure the installation specification conforms with the relevant electrical standard and use professional wiring tools.  You should refer to the installation manual of each product for guidance.

  1. Regularly use a thermal imager to troubleshoot system connection problems, or use the SolisCloud online monitoring platform to perform operation and maintenance inspections to repair faults in a timely manner.


Connection failure is a very serious safety hazard in PV systems. Issues can cause both damage to the system but also reduce the impact of any energy savings factored in at the feasibility stage.

We need to pay attention to installation and construction and later O&M to avoid these problems and improve system safety.

Utilizing online monitoring software such as SolisCloud ensures that any faults can be identified and fixed quickly to avoid costly system downtime.

The content & opinions in this article are the author’s and do not necessarily represent the views of AltEnergyMag


Ginlong's cost-effective solutions for residential, commercial, and utility-scale users deliver value at every level of the solar supply chain, engaging both homeowners and businesses, as well as power producers and renewable energy investors across the globe. Presented under the Solis brand, the company's solar inverter product line uses innovative string technology to deliver first-class reliability, validated under the most stringent international certifications. Combining a global supply chain with world-class R&D and manufacturing capabilities, Ginlong optimizes its Solis inverters for each regional market, servicing and supporting its customers with its team of local experts.

Other Articles

Talking RE+ with Solis Inverters
Attendees can use tablets and phones to get online and check out the SolisCloud monitoring platform with cutting edge features for homeowners and PV system fleet managers.
Solis Inverters at RE+ 2022
Attendees will see new energy storage options for residential and commercial PV applications with Powerhub (our upcoming energy management system). Meanwhile, Solis will provide attendees with SolisCloud – our latest monitoring platform of interactive experience.
2022 Top Article - New Solis 1000 Vdc / 480 Vac PV String Inverters
By combining the dc combiner box, dc disconnects and inverter into one enclosure can be especially profitable in re-powering situations where there has been noticeable corrosion in combiner boxes and at dc disconnect switches / fusing within the array field.
More about Solis

Comments (0)

This post does not have any comments. Be the first to leave a comment below.

Post A Comment

You must be logged in before you can post a comment. Login now.

Featured Product



GenStar MPPT is the industry's first fully integrated solar DC charging system, an all-new design with "lithium DNA" from the leader in charge controllers. Out of the box, GenStar is an overachiever-delivering legendary Morningstar quality, efficiency, power and reliability along with the latest in advanced communications and control technologies. All the most installer-requested features are on-board; additional features can be easily added via Morningstar's ReadyBlock expansion technology, with snap-in blocks that provide battery metering and monitoring, signaling and load control, and lithium battery communications/control