Plug-In Solar in the USA: Eight States Have Now Signed Laws and California Could Be Next
When we published our first US plug-in solar guide earlier this year, Utah was the only state with a law on the books. Five months later, eight states have signed legislation, ten have passed bills with more in the pipeline, and the largest rental market in the country is weeks away from a vote that could change the economics of plug-in solar across America.
This is the biggest story in global plug-in solar right now, and it has direct relevance to the UK market too. The products certifying for the US market, the pricing pressure from growing US demand, and the legislative template being copied state by state are all shaping what happens here. Here is the full update.
The states that have passed laws
Eight states have signed plug-in solar into law as of August 2026. The legislation in each case follows a similar framework: systems up to 1,200W (or in one case higher) can connect to standard household outlets without utility pre-approval, interconnection agreements, or fees. Anti-islanding protection is required. Utah wrote the template and everyone else has copied it.
Utah was first. HB 340 was signed in May 2025 and treats compliant systems as appliances. No interconnection agreement, no utility approval, no fees. Systems must have anti-islanding protection. Limit: 1,200W.
Virginia signed HB 395 and SB 250 in April 2026. Most provisions took effect 1 July 2026. Limit: 1,200W. Utilities cannot require pre-approval.
Maine signed LD 1730 on 6 April 2026, effective early July 2026. Systems up to 420W can be self-installed with no utility notification at all. Systems from 420W to 1,200W require a licensed electrician and utility notification within 30 days. Utilities cannot require interconnection agreements or charge fees.
Maryland signed the Utility RELIEF Act (HB 1532) on 12 May 2026, taking effect immediately. Limit: 1,200W. Systems at or below 391W are exempt from UL certification requirements. Utility notification required after installation but pre-approval cannot be demanded.
Colorado signed HB 26-1007 in May 2026. This is the most generous law yet — a 1,920W limit per meter, 60% higher than the 1,200W cap in every other state. Takes effect 1 January 2027.
Connecticut signed HB 5340 in May 2026.
Vermont signed S 202 in 2026. Limit: 1,200W.
New Hampshire signed SB 540 in May 2026. Limit: 1,200W.
New York and New Jersey: passed, awaiting the governor
New York’s SUNNY Act (S 8512C / A 9111C) cleared both houses in June 2026 and is on Governor Hochul’s desk. New Jersey’s Garden State Balcony Solar Act (S2368) passed the legislature unanimously in July 2026 and awaits the governor’s signature. Both are expected to be signed. Neither is law yet, but both are close enough that buyers in those states should be making purchasing plans now.
New York is significant not just for its size but for its electricity rates — Con Edison customers in New York City pay some of the highest residential rates in the country. The savings potential there is substantially higher than the national average.
California: the bill the whole industry is watching
California SB 868, the Plug and Play Solar Act, introduced by Senator Scott Wiener, passed the full Senate 35-1 on 20 May 2026. It cleared the Assembly Utilities and Energy Committee 18-0 on 10 June 2026. It now sits in Assembly Appropriations, which will hear it in August. The Assembly must pass it by 31 August 2026. If Governor Newsom signs, it takes effect 1 January 2027.
The numbers explain why California matters so much. It has the largest renter population of any US state. It has the second-highest electricity rates in the country, with PG&E customers paying rates that have increased significantly over the past few years. Depending on the model and the home, a plug-in solar system can save a California household up to $450 per year. At the top of the savings league table, Hawaii leads at $455 per year from an 800W system — California is second at $355.
Senator Wiener’s own statement captures it well: “The cost of electricity has risen to absurd levels, and plug-in solar is an easy way families can lower costs.” The bill has near-unanimous support at every stage. The only real obstacle is time — the Assembly has until 31 August and if it does not pass by then, the bill would need to be reintroduced in a new session.
The UL 3700 standard: America’s version of the IPS
The US equivalent of the UK’s Interim Product Specification is UL 3700, published by UL Solutions in January 2026. This is the certification standard that a complete plug-in solar system must meet to be legally sold for residential socket connection in states that have passed laws. It covers the whole system — panels, inverter, cable, and plug — not just the inverter in isolation.
Most state laws either require UL 3700 certification or reference UL 1741 for the microinverter specifically (the established certification for grid-interactive inverters). The principle is the same as the UK’s framework: the certification covers the complete product, anti-islanding is mandatory, and the device must be sold as a tested unit rather than as components you assemble yourself.
Products currently selling well in the US plug-in solar market include the EcoFlow STREAM Microinverter, Hoymiles HMS-800, and Anker SOLIX RS40P. All three are also the leading candidates for UK IPS v2.0 certification. The markets are converging around the same products.
What the US watt limit difference means
Most US state laws cap systems at 1,200W. Colorado goes to 1,920W. The UK cap under SI 2026/848 is 800W. That gap matters in practice. A 1,200W US system with three 400W panels produces around 50% more electricity annually than an 800W UK system with two panels. Colorado’s 1,920W limit would allow four 480W panels — roughly equivalent to an EcoFlow STREAM Ultra’s full MPPT capacity.
The UK’s 800W limit was set cautiously for the first phase of regulation. The government has committed to reviewing it, and the US state experience with 1,200W systems operating without incident will be useful evidence in that review. It is not unreasonable to expect the UK limit to increase in a future amendment.
35 states have introduced legislation
As of 2026, 10 states have passed plug-in solar laws and 35 states in total have introduced legislation. The states with active bills moving through their legislatures include Arizona, California, Illinois, Massachusetts, North Carolina, and others. The legislative momentum is consistent — once one state in a region passes a law, neighbouring states tend to follow within months. The northeast cluster of Vermont, New Hampshire, Connecticut, New York, New Jersey, and Massachusetts is already well advanced.
Three states have seen bills fail or stall so far: Wyoming, Oregon, and Missouri. None have passed explicit bans. The landscape in states without laws is a legal grey area rather than outright prohibition — buying and owning plug-in solar is legal everywhere in the US, but whether you need to notify your utility before connecting depends on where you live.
What this means for UK buyers
The US market developing at this pace matters for the UK for three reasons.
Product availability and pricing. The manufacturers certifying for the US market — EcoFlow, Hoymiles, Anker — are the same manufacturers working through UK IPS v2.0 certification. Growing US demand accelerates their investment in certified products and drives down component costs globally. The UK launch in August 2026 benefits from a supply chain that is already scaling for the US market.
The 1,200W precedent. Eight US states running 1,200W systems without issue strengthens the case for the UK to raise its 800W limit in a future review. The safety evidence from Utah, which has been running the most mature plug-in solar market in the US since May 2025, is directly relevant to that argument.
What to watch next. The California Assembly vote by 31 August is the biggest near-term event in global plug-in solar. If SB 868 passes and is signed, it will trigger a wave of coverage, investment, and product development that benefits every market including the UK.
For everything about the UK regulatory position, see our article on plug-in solar becoming legal in the UK from 27 August 2026 and the rules and regulations page. Our original US plug-in solar guide covers the basics for American readers in detail, including panel positioning by state latitude.
If you are reading this from the US, the state tracker at pluginsolarhub.org is the most up-to-date resource for your specific state’s current legal status. Leave any questions in the comments below.