Plug-in solar by state › New Hampshire
Signed, takes effect January 1, 2027Law checked Oct 13, 2026 against SB 540-FN final version (Chapter 262) · Last change: effective date corrected to January 1, 2027; connection, listing, fee and net-metering rows rewritten to the final text · Change log
New Hampshire’s law was signed July 2, 2026 and takes effect January 1, 2027. A building-code section waits on a Department of Energy certification. It’s written around the inverter’s AC output and one system per metered customer.
What you can build today
Not in effect until January 1, 2027. Then: lab certification to plug-in safety standards, with building-code rules still pending a Department of Energy certification.
Always an option: a permitted, hardwired system under NEC 690 and 705 with your utility’s approval, or an off-grid power station that never connects to house wiring. UL Solutions notes the 2026 NEC “does not recognize the use of plug-in photovoltaic (PIPV) modules”; NFPA expects them in the 2029 edition (source). Where a law requires the NEC and gives no size waiver, the inspector decides. Sun Safe’s reading, not legal advice.
- Limit
- 1,200 W AC inverter output, one per metered customer
- Law
- SB 540-FN
- Signed
- July 2, 2026
- Effective
- January 1, 2027 (building-code section after a DOE certification)
What the law says
| Size limit | 1,200 W AC inverter output |
|---|---|
| How it’s measured | One system per metered customer. |
| Connection | Through a receptacle or other non-permanent wiring connection (RSA 362-A:1-a, IV-a). |
| Purpose | Intended to offset part of the customer’s own on-site use. |
| Listing | Certified by a nationally recognized testing lab to national safety standards for distributed energy resources and plug-in systems (RSA 362-A:10, I). Building-code rules follow once the DOE certification is made. |
| Utility approval and fees | No interconnection review or agreement, no approval and no extra equipment. No fee related to the system, except charges it incurs through its use (RSA 362-A:10, III). The utility may set up an informational notice of the device’s wattage. |
| Power sent to the grid | Not addressed by the law. The Department of Energy will publish consumer information, including on meters, billing and insurance. |
| Utility liability | The utility isn’t liable for damage from the device (Sec. 4). |
| Renters and HOAs | Not addressed. |
In the law’s words
Short excerpts from SB 540-FN, Chapter 262, final version, quoted as written and checked word for word against the official text on October 13, 2026; each with what it means for a plug-in design.
9 excerpts with what each means
- Definition
“…connects to a building's electrical system through a receptacle or other non-permanent wiring connection.”
RSA 362-A:1-a, IV-aA receptacle or other non-permanent connection. - Size
“Each metered customer shall be allowed a maximum of one plug-in solar generation system … with a maximum inverter output of 1,200 watts AC.”
RSA 362-A:10, IVOne system per metered customer, up to 1,200 W AC. - Certification
“…shall be certified by a nationally recognized testing laboratory to meet nationally recognized safety standards.”
RSA 362-A:10, ILab certification to national safety standards; UL 3700 isn’t named. - Building code
“Each plug-in solar generation system shall be installed and operated in accordance with the state building code”
RSA 155-A:16 (Ch. 262:3)Building-code rules wait on a Department of Energy certification. - Utility approval and fees
“An electric distribution utility shall not require a customer using a compliant plug-in solar generation system to: … Pay any fee related to the system, except any charges the system incurs through its use”
RSA 362-A:10, IIINo approval; no fee except charges from use. - Interconnection
“…Complete an interconnection review or obtain an executed interconnection agreement;”
RSA 362-A:10, III(b)No interconnection review or agreement. - Notice
“…may develop a method for the customer to inform the electric distribution utility of the wattage. … Such information shall be for notification purposes only.”
RSA 362-A:10, IIThe utility may set up an informational wattage notice. - Utility liability
“An electric distribution utility shall not be liable for damage, injury, or compensation”
RSA 374:1-b (Ch. 262:4)The utility isn’t liable. - Effective date
“Section 3 of this act shall take effect as provided in section 6 of this act. … The remainder of this act shall take effect January 1, 2027.”
Ch. 262:7January 1, 2027; building-code section later.
What it means for your design
- One system per metered customer: plan one inverter with an AC rating of 1,200 W or less.
- Wait for January 1, 2027 before relying on the exemption.
- The law allows a receptacle or other non-permanent connection; the NEC still applies to the outlet and circuit. Outdoor receptacles need GFCI protection and an in-use cover.
- Building-code rules for these devices come after a Department of Energy certification, so expect more specific rules later.
- The law doesn’t say whether exported power is paid. Size to daytime use.
Designs that fit, and one that doesn’t
The engineering behind it
Why the circuit matters as much as the law, in four short points.
Circuit current, continuous output, outdoor outlets, AC vs panel watts
Why the circuit matters. A plug-in inverter pushes current into a branch circuit from the outlet end. The breaker in your panel only sees the current coming from the panel, not what the inverter adds. With other loads on the same circuit, part of the wire can carry the breaker’s full rating plus the inverter’s output without anything tripping. At 1,200 W the inverter adds 10 A at 120 V. That’s why we recommend a dedicated circuit for any plug-in system, even where the law doesn’t require one.
Continuous output. Code treats inverter output as continuous and sizes the circuit at 125% of it (NEC 705.28): 1,200 W is 10 A, times 1.25 is 12.5 A, which fits a 15 A circuit. Anything over 1,440 W needs a 20 A circuit.
Outdoors. Outdoor receptacles need GFCI protection (NEC 210.8) and an in-use weatherproof cover (NEC 406.9).
AC, not panel watts. These laws limit what the inverter puts out, not what the panels are rated for. You can put more panel on a small inverter; it trims the brightest hours and fills out the rest of the day. The Designer models that trimming hour by hour.
Questions
Is plug-in solar legal in New Hampshire?
From January 1, 2027. SB 540 (Chapter 262) was signed July 2, 2026; the final text sets January 1, 2027 for the rest of the act (Sec. 7).
How big can plug-in solar be in New Hampshire?
1,200 W of AC inverter output, one system per metered customer.