• UL Solutions has launched a dedicated testing and certification program for plug-in solar systems, also known as balcony solar, creating a clear safety framework to support their installation and use across the United States.
• The program establishes construction, performance and labeling criteria that help manufacturers design plug-in solar products meeting safety standards.
• By addressing safety risks associated with plug-in solar systems, UL Solutions is helping to enable safer, more accessible solar power options for residents of multi-unit buildings and supporting emerging state-level legislation.

UL Solutions (NYSE: ULS), a global leader in applied safety science, today announced that it has launched a plug-in solar system testing and certification program, establishing a clear, dedicated testing framework that will help provide a pathway for the safer adoption of this energy generation technology.

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UL Solutions has launched a dedicated testing and certification program for plug-in solar systems, also known as balcony solar, creating a clear safety framework to support their installation and use across the United States.

The new program is an evaluation based on UL 3700, the Outline of Investigation for Interactive Plug-In Photovoltaic Equipment and Systems. It defines construction, performance and labeling criteria tailored to plug-in solar systems, also referred to as balcony solar, offering manufacturers a reliable foundation for designing products that consistently meet safety and performance requirements.

“Our new plug-in solar system certification program gives manufacturers and consumers the clarity they need to embrace plug-in solar systems with confidence,” said Ken Boyce, vice president, Principal Engineering, Industrial Testing, Inspection and Certification, at UL Solutions. “By defining how these systems must be built, evaluated for safety and safely installed, UL 3700 helps mitigate potential risks, and opens a path for more people to access resilient solar power.”

Legacy plug-in solar systems that have been used outside the U.S. differ from permanently wired rooftop solar panels because they are intended to connect to household circuits through a plug and receptacle. That simplicity makes solar easier to adopt, but it also brings certain risks, such as systems becoming overloaded and the possibility of power flowing back into lines.

In addition to defining safety standards for manufacturers, UL 3700 addresses these additional risks by requiring features that mitigate accidental contact with hazardous electric parts, promote safe installation, protect against overloads and prevent electric current from flowing in the wrong direction. Plug-in solar systems certified to UL 3700 could be suitable for renters and homeowners who are unable to install rooftop systems and could be used to provide back-up power for essential devices during outages.

Interest has been amplified by recent policy changes. Earlier this year, Utah became the first state to allow use of up to 1.2 kW plug-in solar panel systems without seeking utility approval. Other states, including Maryland, Minnesota, New Hampshire, New York, Pennsylvania, Vermont and Virginia, are considering similar legislation. UL 3700 can support state legislative and regulatory efforts with a clear framework to enable the safety of the product and its installation.

“UL 3700 marks a major step forward, helping remove regulatory uncertainty and making plug-in solar a potential choice for consumers across the U.S.,” said Robert Slone, chief scientist and senior vice president at UL Solutions. “By addressing key safety gaps that could slow adoption, we are helping to make plug-in solar a viable option that complements larger rooftop systems and supports a stronger, more reliable energy future.”

About UL Solutions

A global leader in applied safety science, UL Solutions (NYSE: ULS) transforms safety, security and sustainability challenges into opportunities for customers in more than 110 countries. UL Solutions delivers testing, inspection and certification services, together with software products and advisory offerings, that support our customers’ product innovation and business growth. The UL Mark serves as a recognized symbol of trust in our customers’ products and reflects an unwavering commitment to advancing our safety mission. We help our customers innovate, launch new products and services, navigate global markets and complex supply chains, and grow sustainably and responsibly into the future. Our science is your advantage.

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