UL 3700 explained
UL 3700 is the safety document UL uses to certify plug-in solar equipment in the U.S. Several state laws now require it or something equivalent, and only a few products claim it so far.
Published by ChoiscoPublished Oct. 2, 2026Last verified
The facts
- Full name
- UL 3700, Outline of Investigation for Interactive Plug-In PV (PIPV) Equipment and SystemsVerifiedSource: UL Standards store listing
- What kind of document
- An Outline of Investigation: the document UL certifies new product types against while a full consensus standard does not yet exist.VerifiedSource: UL Solutions, Jan. 8, 2026
- Certification launched
- January 8, 2026, when UL Solutions announced testing and certification for plug-in solarVerifiedSource: UL Solutions, Jan. 8, 2026
- Published
- December 11, 2025 (edition number listed differently by different stores)ReportedSource: UL Standards store listing
- What it covers
- Plug-in PV equipment and systems connected through a cord to a permanently installed receptacle, including overloading the branch circuit, reverse power flow and touching live plug pins. Panels limited to 64 V DC open circuit. Excludes rooftop, building-integrated and hard-wired systems.Reported
From the UL store summary of the document.
Source: UL Standards store listing
Which state laws require it
- Maine, Vermont and New Jersey name UL 3700 in the law (or a comparable standard).
- California requires certification "as a plug-in photovoltaic system" without naming UL 3700, which points to whole-system certification.
- Connecticut names UL 1741, the general inverter standard.
- Utah, Colorado, Maryland and Virginia require certification by UL or another nationally recognized testing laboratory without naming a standard.
Which products claim it
- Bright Saver Balcony Solar Kit: Says the microinverter has UL 1741 and a UL 3700 subassembly certification. Bright Saver itself says the kit is not yet certified as a whole system.
- Mango Power S 1200W Plug-In Solar Kit: Says it is certified by Intertek to UL 3700 (announced Sept. 18, 2026), plus UL 1741 SA/SB and CSA C22.2. The release does not say whether the listing covers the whole kit or the microinverter.
- Craftstrom Plug&Play 1200 Watt Eco-Line: Says the inverter is "ETL certified to UL 1742 and IEEE 1547" (likely meaning UL 1741) and the system is "UL 3700 compliant". Compliant is not the same as certified, and no certifying lab is named for UL 3700.
- Hoymiles HiFlow Pro Microinverter: Calls itself the first "UL 3700-compliant" plug-in microinverter, plus UL 1741 SB and IEEE 1547. No certifying lab is named for UL 3700.
- APsystems EZ1 Microinverter: Says "CSA certified to UL 3700" (announced July 2026), plus UL 1741 SB. No certificate number given.
- EcoFlow STREAM Microinverter: Lists UL 1741. No UL 3700 claim on the page.
Shown as each maker states it until we confirm the listing in the UL, Intertek or CSA directory.
Note the difference between a component (a microinverter) being certified and a complete system being certified; California requires the latter.
Other standards you will see
- UL 1741: inverters and other equipment that connect power sources to the grid. Not specific to plug-in solar.
- IEEE 1547: how equipment connected to the grid must behave. Vermont and Connecticut cite it.
- UL 9540: energy storage systems, relevant to plug-in batteries.