Underwriters Laboratories (UL) is the mostly used US-body to certify solar panels for the US market and issues the prominent UL 1703 certification.
About Underwriters Laboratories (UL)
UL is an independent, privately held product safety consulting, testing and certification company. Founded in 1894, it is one of the major Nationally Recognized Testing Laboratories (NRTL) in the USA, approved by the Occupational Safety and Health Administration (OSHA).
Underwriters Laboratories comprises a network of over 60 research, product quality testing and certification facilities and its quality mark - the UL Mark - enjoys great international recognition. Over the years, UL has expanded its business scope beyond electrical appliances to areas such as product substance quality testing as well as food and water safety.
Are UL certifications required for solar panels in the USA?
UL is the mostly used US-body to certify solar panels for the US market. Solar panels with an UL mark may be connected to the grid, may receive government rebates & tax incentives and may also be covered by insurances whereas solar panels without UL mark will hardly be entitled to these advantages.
For solar panel quality and safety, the UL 1703 certification applies. The UL mark is not required by law, however it may be extremely difficult to sell solar panels in the USA without an UL Mark.
About the UL 1703 certification
UL 1703 covers flat-plate photovoltaic modules and panels that comply with the National Electric Code (NEC), OSHA, the National Fire Prevention Association, and will be readily accepted by local inspectors in the USA.
UL 1703 is mostly identical to the IEC 61730 solar panel safety qualification standard, however there are some differences in terms of design, material and testing requirements, such as for example edge distances and individual component testing.
The UL 1703 standard also means that the performance of the panels has been tested and has been found to perform to at least 90% or more of the manufacturers stated power rating. UL 1703 is scheduled to eventually be superseded by IEC 61730 once it becomes standard in the USA and Canada.