Mr. Joseph Yang, Director of Stäubli (headquartered in Switzerland) in a recent interview with us.

“When using cable connectors that are not suitable for solar power systems, you will not realize potential dangers until the power system is broken.” Those are the sharings of Mr. Joseph Yang, Director, Electrical Connectors (ECS) of Stäubli (headquartered in Switzerland - Taiwan branch) in a recent interview with us, HELUKABEL Vietnam.


During his visit to Vietnam to attend the "CABLE & ACCESSORY SOLUTIONS FOR PHOTOVOLTAIC SYSTEMS" seminar, was organized by us, HELUKABEL Vietnam, Mr. Joseph Yang, Director, Electrical Connectors (ECS) of Stäubli (Taiwan branch) agreed to become a special guest on episode 2 of our Podcast program.

Before working at Stäubli for more than six years, he worked at an IPO company - a company specializing in investing in the field of solar power systems in Taiwan. During that time, he has done more than 100 solar rooftop projects and worked in the US for one year. Up to now, Joseph has more than eight years of experience in the Photovoltaics sector. Let's follow his sharing on this field in our interview.

Mr. Joseph Yang, Director, Electrical Connectors (ECS) of Stäubli (headquartered in Switzerland - Taiwan branch).
Mr. Joseph Yang, Director, Electrical Connectors (ECS) of Stäubli (headquartered in Switzerland - Taiwan branch).

Stäubli is a global mechatronics solutions provider with four dedicated divisions: Electrical Connectors, Fluid Connectors, Robotics, and Textiles. Among these, Stauli is most known for electrical connectors. What is the story behind this and why is it so?

The Stäubli company is a merger of the two companies Multi-Contact and Stäubli. The name of the company is taken from the name of the Swiss founder - Hermann Stäubli.

Multi-Contact company is known as the first generation in the field, we initially imported their products for installation in the textile machine. About 30 years ago, the Multi-Contact company did not have a sales team to sell products, so we agreed on a good relationship to merge into the company Stäubli Multi-Contact, which manufactures and supplies all the electrical connectors products globally. In 2017, the trademark Stäubli Multi-Contact after the merger took effect until now.

*Rudolph Schelling and Hermann Stäubli together founded a factory in Horgen, Switzerland, which has since grown into a leading global group of mechatronic solutions called Stäubli.

Currently, the MC4 connector is used in Photovoltaic systems. So, in addition to this field, is the MC4 also used in other fields?

Our connector products not only focus on the field of Photovoltaic but also apply to many other fields that require less than 100 times of twisting and focus on DC voltage below 1000V, you can use MC4 for ESS (energy storage system) application, this is an area that will grow in the future.

*ESS is energy storage systems, which are devices that enable energy from renewables, like Photovoltaics & wind, to be stored and then released when customers need power most.

In the Photovoltaics system, how does the MC4 connector work to limit the short circuit in the joints?

Currently, most technical failures in PV systems are usually related to cross-mating, which means that junction A will connect to junction B. This connection requires a different technique than connecting a socket path to a block part. Meanwhile, our MC4 connector has a core technology that not everyone can copycat 100%, which also results in a significant difference in contact resistance and chemical resistance of the connector.

In case cross-mating is not good in the projects, the problems will appear after 2-3 years of operation, and the PV system will start to break. Projects across the globe are interested in limiting this undesirable situation.

When using unsuitable connectors in a solar power system, you will not be able to realize the danger that exists at the first time because the resistance is low, but the temperature between the cross-mating of the connector has always existed. If you use infrared to look at the connector you will notice it will be redder and hotter. After use for 2 to 3 years, the connector will break and be damaged. In addition, when the contact resistance and temperature also increase, at this time the plastic parts and the DC connectors placed close together will be arced (damaged and even burned the solar power system).


Mr. Joseph Yang shared his technology experience in the "CABLE & ACCESSORY SOLUTIONS FOR PHOTOVOLTAIC SYSTEMS" seminar.
Mr. Joseph Yang shared his technology experience in the "CABLE & ACCESSORY SOLUTIONS FOR PHOTOVOLTAIC SYSTEMS" seminar.
Mr. Prapan Angsuthasawit - Director of HELUKABEL Vietnam and Mr. Joseph Yang in the seminar.

Solar systems work in harsh outdoor weather conditions, so how is the MC4 connector designed to ensure that it still works well without being affected by the weather?

Our products are IEC compliant to ensure MC4 performs well in outdoor conditions. Products must meet a standard of -42 to 225 degrees Celsius, which is the leading standard in the market. Besides, the operating temperature from -10 to 90 degrees Celsius is also the standard that our products achieve. In addition, products must comply with certification guidelines for quality assurance in different countries, in which UL certification is the standard that most customers follow.

How does the choice of MC4 connector depend on the cable used by the project?

There are many brands of solar power cables on the market, but to be able to connect between solar power cables and MC4 connectors, you need to understand the usage situation and diameter of the power cables, then the appropriate connector can be selected.

In addition, solar power cables must also meet international standard certifications because this is the first element that investors will require for their projects. Next, the PV cable must also have a good heat resistance layer to be able to install the connector with the power cable in the system.

In the future, what are Stäubli's plans to continue to improve the MC4 connector and how will the company's new orientations change?

We call MC4 EVO2 – meaning evolution, we have been selling this product since 2016 and the first market is in Europe. In 2019, we started to expand our market and supply products in Asia, which is a growth and expansion.

In the future, we will continue to invest in the development of product quality. At the same time, we will also pay more attention to the field of Photovoltaic and get more information about the eBOS sector (Electrical balance of system) to help reduce installation costs. Currently, we are also working on new products, if it is released, you can use both products to save costs from 5 to 8%.

In conclusion, the connector is a small device but has a great influence on the Solar power system. When installing a Photovoltaic system, you need to choose the right type of cable with heat resistance and a suitable diameter for the connector. In particular, the connectors should be used with the same brand to have similar specifications. This is to ensure that the electrical system will have good cross-mating and performance. In many solar power projects in Vietnam, our solar cable products and Stäubli's MC4 connectors are used together to contribute to stable signal and power transmission throughout the system.

We, HELUKABEL Vietnam, appreciate the enthusiastic support from Mr. Joseph Yang, as well as the Stäubli company. Hopefully, in the future, HELUKABEL and Stäubli will be close companions to grow stronger together globally.