Inverters, grid connection and plug-in solar

When a Balcony Solar Kit Says "UL 3700," What Exactly Is Certified?

Published · By the SolarPanelX editors · Prices and specs as of that date, from the pages under Sources

Summary

As of July 2026, the UL 3700 certifications announced in the U.S. cover microinverters, not whole kits. Hoymiles and APsystems each announced a certified microinverter, and Environment America said on July 24 that no whole-system kit, one box with a panel, inverter, and plug, had received UL 3700 certification. California's SB 868 would require certification of the kit as a plug-in photovoltaic system.

The standard

UL Solutions introduced UL 3700, an Outline of Investigation for Interactive Plug-In Photovoltaic Equipment and Systems, in January 2026. When the California Assembly's utilities committee reviewed SB 868 that June, it wrote that, to its knowledge, no commercially available balcony solar system had achieved the certification; individual components had, but not the full kit as the law requires.

Component versus system

In July, Hoymiles launched the HiFlow Pro as the first U.S. microinverter certified to UL 3700, and APsystems announced that its EZ1 microinverter was CSA certified to UL 3700. Both announcements concern the inverter. The panels, cables, and plug that ship alongside it are outside that certification, so "UL 3700" on a product page can mean two different things depending on whether it refers to the microinverter or the complete system.

The state laws do not word this the same way.

StateCertification language
Utah (in effect)Certified by Underwriters Laboratories or an equivalent nationally recognized testing laboratory
Virginia (effective January 2027)Certified by a nationally recognized testing laboratory under 29 C.F.R. § 1910.7, or an equivalent
California (SB 868, awaiting the governor)Certified as a plug-in photovoltaic system, plus a separately certified feature that isolates the device from the building during an outage

None of the three names UL 3700 itself.

Sources

  1. UL Solutions — Testing and Certification Framework for Safer Plug-In Solar Across the United States (January 8, 2026)
  2. Environment America — Plug-in solar takes step forward with first national safety certification (July 24, 2026)
  3. APsystems — EZ1 UL 3700 Certified (July 15, 2026)
  4. Electrek — Hoymiles HiFlow Pro, first US UL 3700 microinverter (July 20, 2026)
  5. California Assembly Committee on Utilities and Energy — SB 868 analysis (hearing June 10, 2026)
  6. LegiScan — California SB 868 enrolled text (August 28, 2026)
  7. Utah Code §54-15-102 (effective 5/7/2025)
  8. Code of Virginia §56-596.8 (effective January 1, 2027)

We have not tested these products. Specs, prices, stock and terms are as published on these pages on the date above and can change; check the manufacturer or retailer before you buy.

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