Solar installations driving down costs and increasing efficiency with 1000 volt systems

The majority of certified PV modules and Balance of System (BoS) Components (inverters, combiner boxes, wiring harnesses, connectors, etc.) have been tested and certified for use at a maximum system voltage of 600 Volts.

07 March 2014

The photovoltaic (PV) system installation industry is moving to 1000 volt systems due to significant efficiencies being realized. In order to meet this demand, module and component manufacturers must approve their products for 1000 system voltage operation and update their product certification listings. The safety standard for "Flat-Plate Photovoltaic Modules and Panels," ANSI/UL 1703, allows for a maximum system voltage of 1000 volts.

The majority of certified PV modules and Balance of System (BoS) Components (inverters, combiner boxes, wiring harnesses, connectors, etc.) have been tested and certified for use at a maximum system voltage of 600 volts. These PV Modules listed to the existing ANSI/UL 1703 standard (ULC ORD C1703) are intended for installation on or integrated with buildings - or to be freestanding - in accordance with the National Electrical Code, NFPA 70.

For system installations at 1000 volt, all components must be listed to 1000 volts. For example, PV modules are normally connected in series where, if limited to 600 volts you could for a typical 48 cell module, string together 25 PV modules to achieve 600 volts Maximum System Voltage. If the module and all components are rated for 1000 volts maximum system voltage operation, you can string together 41 PV modules allowing for a simpler installation and overall cost reduction. Higher voltage operation allows the inverters to run at a more efficient operating point and therefore more electricity will be generated. Installation costs are reduced because fewer inverter and combiner boxes are needed, which also reduces maintenance costs. A typical 1 MW installation could save about 40 percent BoS costs, which could be about $20,000–30,000 for the overall installation.

PV modules will need to go through additional testing to verify compliance at 1000 volts and, if successful, the existing listings to ANSI/UL 1703 and the ULC ORD C1703 can be updated. If the module has been previously tested and approved for 1000 volts operation under the IEC 61730-1 and IEC 61730-2 and IEC 61215 for crystalline silicon or IEC 61646 for thin film, a 1000 volt certification to ANSI/UL 1703 could be achieved with reduced testing requirements. Intertek can evaluate the module and module components (j-box, cable, and connectors) and BoS components to verify that they are acceptable for use in 1000 volt systems.

Have a question about listing your PV module or BoS component to 1000 volts? Let us know how we can help. Also, please feel free to leave a question or comment below, and one of our experts will get back to you.

Today’s expert blogger is Sunny Rai, Intertek’s Regional Vice President for Renewable Energy. Sunny provides strategic direction for Intertek’s photovoltaic, wind, smart grid, and semiconductor businesses. He is based in our Menlo Park, California testing laboratory, but you may find him speaking at industry events and conferences around the world.