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Mersen Announces 800VAC Fuses and Switchgear for Solar Systems with PV String Inverters

July 20, 2020 by Hailey Stewart

Mersen introduces the extension of its Photovoltaic portfolio to support the development and the deployment of the 800V AC string inverters in PV installations

Mersen (Euronext FR0000039620 – MRN), is proud to introduce the extension of its Photovoltaic portfolio to support the development and the deployment of the 800V AC string inverters in PV installations. 

PV energy should no longer be considered as an alternative source of energy. It is now a true reality as it is becoming more and more cost-effective. One of the main reasons is the reduction of installation and maintenance costs. 


Mersen Announces 800VAC Fuses and Switchgear for Solar Systems with PV String Inverters Figure


New technologies help increasing rated voltage in photovoltaic distribution network on both AC and DC sides. In the same time, we can see a tendency to switch from central inverter to several smaller string inverters. These installations work with smaller string inverters close to the photovoltaic panels. At the same time, the transmission of energy at higher voltages makes it possible to reduce power losses and to decrease installation costs. By using upper section cables, up to 300 mm2 for NH 1 and NH 3, the voltage drop is reduced. Thus, the new generation of string inverters will now deliver power up to 800V AC.


String inverter vs central inverter

The residential market represents the main market for string inverters because solar installations on roofs do not require any fuses up to 3 strings. It is therefore recommended to use low power string inverters on this type of installation. For the commercial and industrial sectors, solar systems on roofs are switching from 1000V DC to 1500V DC. For those applications, it is also recommended to install low or medium power string inverters. Finally, for solar farms with 1500V DC ground solar installations, the market is shared between string inverters of medium power and central inverters.


Evolution of PV central technology compared to string Inverter technology to move towards a more DC fuse less system

Today, more and more new photovoltaic systems are using the string inverter solution without DC fuses. Inverter manufacturers increase the AC output voltage up to 800V to reduce the investment cost of the installation and thus reduce power losses. In this case, the AC combiner boxes are used to group several chain inverters and need 800V AC protection. Optimum protection at this rated level is the combination of NH fuses and NH fuse switch-disconnectors: it offers the only integrated solution for protecting, isolating and switching the circuit.


Mersen's new offer for string 800V AC inverter photovoltaic systems

Decades of experience on the NH Fuse-links and on the NH Fuse switch disconnectors through our Multivert® and Multibloc® ranges enable MERSEN to offer a complete solution to our customers, which meets the specific application requirements and delivers high quality products, high level of service and expertise.

Mersen NH 800V AC fuses have been designed specifically for photovoltaic systems with 1500V DC / 800V AC inverters. Thanks to a specific silver fuse element design in comparison to conventional line protection gG class operating fuses, these new 800V AC fuses can interrupt any surge, from the lowest fusing up to 90kAmps at a tested voltage of 880V, in a standard NH type size.

With a gR operating class described both in IEC 60269 standard and UL 248-13, Mersen can provide a fuse offer that is globally accepted, whatever the area of destination is Europe, Asia, South or North America.

Mersen is now the only manufacturer to offer a complete package of NH Fuses & FSDs designed specifically to answer the requirements of protection and distribution of electric networks in the combiner boxes on the AC side of the new string inverters with rated operational voltage of 800 V AC. This new offer includes NH fuse-links, and NH Fuse switch disconnectors, in horizontal version (Multibloc®) and in vertical version (Multivert®). 


The Mersen solution includes:

  • NH Fuse -links size 1 (50A to 160A ratings) & size 2 (200A to 250A ratings)

  • Range of Multibloc 800V AC size 1 & size 2 compatible with fuses size 1 & 2

  • Range of Multivert 800V AC size 1 compatible with fuses size 1 


About Mersen

Mersen, previously called Carbone Lorraine, is a French international company. A global expert in electrical power and advanced materials, Mersen designs innovative solutions to address its clients’ specific needs and enable them to optimize their manufacturing performance. It is based in 35 countries across the globe with 53 production facilities. The company also has 15 Research and Development centers. They provide industrial companies worldwide with innovative solutions enhancing the performance of their products and services. Mersen’s primary objective is to create value for customers. By leveraging our in-depth market knowledge and close customer relationships, we can capture future trends and effectively support industrial businesses in our five core markets.