UL 3700: How to Check a Plug-In Solar Kit Is Really Certified

Short answer: UL 3700 is the first US safety program written for plug-in solar. Its full name is the Outline of Investigation for Interactive Plug-In Photovoltaic Equipment and Systems. It was first published in December 2025, UL Solutions began certifying products against it on January 8, 2026, and a second edition has been in force since October 1, 2026. A kit is only UL 3700 certified if a testing lab’s own directory lists that exact model under UL 3700. A certified microinverter inside the box, or “designed to meet UL 3700” on the label, isn’t the same thing. As of October 12, 2026, three microinverters have component-level UL 3700 certifications, but we haven’t found a complete kit reported as certified.

Why plug-in solar needed its own standard

Home wiring was designed for power flowing one way: from the breaker panel to your appliances. A plug-in system pushes power the other way, into a branch circuit through a receptacle. In its white paper on plug-in PV, UL Solutions describes three problems that creates:

• Overloads the breaker can’t see. A 15 A circuit with appliances drawing 12 A and 8 A would normally trip. Add a solar system feeding about 5 A into that circuit and the appliances can get their 20 A without the breaker detecting an overload, so the wiring can carry more than it’s designed for (pv magazine USA walks through UL’s example).
• Touch safety. The blades of a plug connected to a powered inverter can be live, and a standard three-prong plug was never evaluated as a power source.
• GFCI protection. Ground-fault protection, required outdoors and in wet areas, assumes one-way current and may not work properly with backfeed.

What UL 3700 covers

According to UL Solutions, the program defines construction, performance and labeling criteria for plug-in solar systems, and requires features that:

• protect against accidental contact with live parts,
• promote safe installation,
• protect against overloads,
• prevent current from flowing in the wrong direction, including feeding the grid during an outage.

The first edition’s scope, which UL Standards & Engagement publishes, is more specific about what counts as plug-in solar:

• The connection: equipment with “an AC or DC PIPV interconnection cord with a PIPV plug”, for connection to “a permanently installed PIPV receptacle”. In other words, a plug and receptacle meant for plug-in PV, not necessarily any ordinary wall outlet.
• What’s out: roof-mounted and building-integrated PV, and anything “permanently electrically connected to the premises wiring”. Those are conventional solar installations with their own rules.
• Low-voltage panels: PV modules and DC circuits are limited to a maximum open-circuit voltage of 64 V DC under the outline’s test conditions (80 V once a factor for cold weather is applied).
• The home circuit counts too: the scope applies only to circuits where every component, including connectors, receptacles, GFCIs and overcurrent devices, is “listed and identified for bidirectional current flow”. An ordinary outlet or GFCI in your home may not be.
• Mounting: it covers the maker’s instructions for securing the equipment against wind, snow and other loads, but it “does not evaluate or verify the structural integrity” of the building itself, such as a balcony railing.

What changed in Edition 2? We don’t know yet. UL’s product page for Edition 2 lists it as active from October 1, 2026 and the first edition as superseded, but it shows no scope text and no summary of revisions, and we haven’t found UL or the trade press describing the changes. We’ll update this guide when someone does.

UL’s white paper lists the kinds of engineering answers it expects, among them dedicated circuits with unique receptacles, overcurrent protection at the point of connection, special plug designs and power control systems. That’s why some certified systems may need an electrician to add a dedicated circuit or receptacle, while others may be truly plug and play. It depends on how each maker solves the problems above.

A certified part is not a certified kit

The laws that require certification ask for it at the system level. California’s SB 868 requires the device to be “certified as a plug-in photovoltaic system” by UL or an equivalent nationally recognized testing laboratory, plus a certified feature that isolates it during outages (chaptered text, section 8530). The California Assembly’s committee analysis notes that Utah’s law also requires full system-level certification, and that in June 2026 only individual components, not a complete kit, had been certified.

The first UL 3700 certificates went to microinverters, not kits. Two of them are public, as certificates of compliance from CSA Group, an OSHA-recognized lab, both issued on July 15, 2026 under the first edition:

• Hoymiles HiFlow Pro (models HMS-360 to HMS-500-1WM-LV), certificate 80310016, which Hoymiles launched as the first UL 3700-compliant plug-in microinverter in the US (pv magazine USA, Electrek).
• APsystems EZ1-LV, certificate 80310017.

The certificates themselves are the best evidence that a part is not a kit. Their conditions of acceptability say that each model is a microinverter for which “future evaluation should be considered when forming a complete PIPV system”, that it needs a listed cord with a proprietary, locking PIPV plug matched to a permanently installed PIPV receptacle from the same maker, and that a listed bidirectional Class A GFCI must sit between the system and the branch circuit. The APsystems model is also limited to dedicated circuits on a 10 A breaker (Hoymiles certificate, APsystems certificate).

A third maker shows how easily the words blur. On September 18, 2026, Mango Power’s press release said “Mango Power S has been certified by Intertek to UL 3700”, without saying which part. Its own blog post is clearer: it’s “component recognition for the specified microinverters” (the S Pro), which “does not certify every complete kit or accessory combination”.

Here is how we label these claims today. Both CSA certificates are copies published by others, a nonprofit and a retailer, and we couldn’t open CSA’s own directory to confirm the listings, so they sit one step below Certified on our scale until we can. Intertek’s directory didn’t load for us either.

• Plug-in PV equipment safety, as a componentTest report onlyUL 3700 · CSA Group Test report
• Up to four units in parallel, 1,200 W totalMaker claim only

• Plug-in PV equipment safety, as a componentTest report onlyUL 3700 · CSA Group Test report

• Plug-in PV equipment safety, as a componentMaker claim onlyUL 3700

Even once a microinverter is listed, a kit built around it still needs its own system listing to meet laws like California’s. And all three were certified against the first edition; nothing public yet says how Edition 2 affects them.

Certified

Listed under the named standard in the directory of a nationally recognized testing laboratory (UL, CSA, Intertek/ETL or similar), for this model.

Test report only

The maker publishes an independent test report, but the product is not listed as certified for this claim.

Maker claim only

No certification listing or independent test report that we could find.

How to check a UL 3700 listing yourself

1. Get the exact model number of the kit, not just the brand or the series name.
2. Search the lab’s directory. For UL, that’s UL Product iQ (a free account is needed). Other labs can certify too, such as CSA Group and Intertek (ETL): check that the lab is on OSHA’s list of nationally recognized testing laboratories, then search that lab’s own directory. A certificate PDF from the maker or a store is a good lead, not the listing.
3. Match three things on the listing: the company, the exact model, and UL 3700 as the standard.
4. Check what’s listed: a system (panels, inverter and connection hardware together) or a single component.
5. Read the conditions. Certificates list conditions of acceptability, such as a special receptacle, a GFCI or a dedicated circuit. Those tell you what your home needs, and whether the part still has to be evaluated as a system.
6. Note the edition and the date. The listing or certificate names the edition it was tested against; listings change, and we date every check on this site.

Red flags on a box or product page

• “Designed to meet UL 3700”, “UL 3700 compliant” or “built to UL standards”, with no listing you can find.
• “UL certified components”: the parts may be listed, the kit may not be.
• A UL mark on an inverter or panel, but nothing for the system as a whole.
• A listing for a different model or an earlier version.
• “Certified” in a headline with no word on whether it’s the kit or one part of it.

None of these mean a product is unsafe. They mean the claim hasn’t been confirmed, and in states that require certification, an unconfirmed kit may not get the law’s protections.

Bottom line

UL 3700 gives plug-in solar a real safety benchmark, and laws like California’s SB 868 lean on it. Until a complete kit shows up in a lab’s directory, read every “certified” claim as being about a part, and check it yourself. New to the topic? Start with what plug-in solar is, then see our kit guides as certified systems arrive.