Keyur Rakholiya UL 1703 is the legacy Underwriters Laboratories safety standard for flat-plate photovoltaic modules and panels sold in North America. It covered electrical safety, fire classification and mechanical strength. UL 61730, first published in 2017 and harmonized with IEC 61730, has replaced it for new module listings, so designers check which standard appears on datasheets.
What is UL 1703?
UL 1703 is the older North American safety standard for flat-plate PV modules. This page is for solar designers and permit reviewers who find UL 1703 on a datasheet or nameplate and need to know how it compares with UL 61730.
Key Takeaways
- UL 1703 = legacy PV module safety listing.
- Superseded by UL 61730 (international alignment).
- Existing modules with UL 1703 still permitted.
- New modules use UL 61730.
What is the difference between UL 1703 and UL 61730?
UL 1703 was the original North American safety listing for flat-plate crystalline PV modules, covering electrical safety, fire classification, and basic mechanical durability. Starting in 2020, UL began transitioning module certification to UL 61730, which harmonizes US requirements with the international IEC 61730 standard and adds more rigorous mechanical and environmental durability testing.
The practical effect for a solar designer: modules purchased and installed today almost always carry a UL 61730 listing, while older systems already in the field may still show UL 1703 on their nameplate, both are recognized as valid listings for the equipment they were issued to.
Why the Listing Matters at Permit Time
An AHJ reviewing a solar permit package checks the module listing as part of confirming NEC 690.4(B) equipment-listing compliance. Getting this wrong, citing a discontinued UL 1703 listing for equipment that actually ships with UL 61730, or vice versa, is a common source of plan-check corrections that add days to a submittal.
Keeping the equipment cut sheets and listing references in the solar permit design package current with what the manufacturer actually certifies to helps avoid that back-and-forth.
Related Reading
Equipment listings are one of several details an AHJ checks alongside the electrical single-line diagram and structural calculations during plan review, so getting the module and inverter certifications right up front saves review cycles, the Solar Permit Design FAQ walks through the equipment-documentation questions EPCs run into most often before submittal.
For a look at how module safety certification fits alongside inverter-side requirements, Qbits Energy’s guide to solar inverter certification standards covers the equivalent listing requirements on the inverter side, and their IEC 61730 glossary entry is a useful companion for teams sourcing modules for projects outside North America.
Disclosure: Qbits Energy is a Heaven Designs group company.
Frequently Asked Questions
3 commonly searched questions about UL 1703.
Is UL 1703 still valid?
What is the difference between UL 1703 and UL 61730?
Is UL 1730 the same as UL 1703?
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