Enphase IQ9 Commercial Microinverter 427VA Domestic Content 277V Three-Phase EN-IQ9N-3P-277-A-DOM-US

The Enphase IQ9 Commercial Microinverter (EN-IQ9N-3P-277-A-DOM-US) is a 427 VA peak output Enphase commercial microinverter designed for three-phase 480V WYE commercial PV systems operating at 277V line-to-neutral. As the DOM-US variant, its PCBA, electrical parts, and enclosure are manufactured in the United States, making it eligible for consideration under the IRS domestic content provisions for the ITC Domestic Content Bonus Credit — a meaningful financial lever for commercial solar projects where the full bill of materials can be structured to qualify. It integrates with the IQ Gateway Commercial Pro for fleet-scale monitoring and communicates via power line communication (PLC) for streamlined commercial installation.

Note: This is a preliminary product data sheet. The IQ9N-3P-277-A-DOM-US is not yet certified; specifications are subject to change without notice. CA Rule 21 (UL 1741-SB) and IEEE 1547 (UL 1741-SB) compliance certifications are pending. Additionally, the IQ9 generates a single-phase AC output — three-phase configuration on a 480V WYE system is achieved through the use of a three-phase QD cable, not through the microinverter itself. Confirm cable availability and system design with your Enphase distributor before specifying this unit. Consult a qualified tax professional to confirm ITC domestic content bonus adder applicability to your specific project.

Key specifications

• Peak output power: 427 VA; max. continuous output power: 427 VA
• Nominal grid voltage: 277V (L-N) for 480V WYE three-phase systems
• Compatible module power range: 340–600W
• CEC weighted efficiency: 97.5%
• Peak power tracking (MPPT) voltage: 28–45V; operating voltage: 16–60V; min./max. startup: 21/60V
• Max. DC continuous current (module Imp): 16A; max. module Isc: 20A; max. short-circuit DC input: 25A
• Max. continuous output current: 1.54A @ 277V (L-N)
• Max. microinverters per 20A 480V WYE three-phase branch circuit: 30
• AC connector: Enphase QD 4-pin; DC connector: Stäubli MC4
• Dimensions (H × W × D): 8.12 × 7.32 × 1.23 in. (206.48 × 186.03 × 31.25 mm); 2.65 lbs. (1.2 kg)
• Environmental rating: NEMA Type 6; approved for wet locations; operating range -40°F to 149°F (-40°C to 65°C); altitude <9,842 ft. (<3,000 m)
• Communication: Power line communication (PLC); monitoring via Enphase App
• Gateway compatibility: IQ Gateway Commercial Pro (GW0-1CL-1N-D0-0R)
• Standards (pending): CA Rule 21 (UL 1741-SB), UL 62109-1, UL 1741/IEEE 1547, FCC Part 15 Class B, CAN/CSA-C22.2 No. 107.1-01; NEC 2014/2017/2020/2023 §690.12 PV Rapid Shutdown
• Warranty: 25-year limited

480V WYE three-phase commercial system design

The IQ9N-3P-277 is purpose-built for the 480V WYE grid configuration prevalent in North American commercial buildings — operating at 277V line-to-neutral, the standard phase voltage on 480V WYE services. Up to 30 units fit on a single 20A three-phase branch circuit, significantly higher than the 10–12 units typical of residential IQ8 Series branch circuits and well-suited to commercial rooftop arrays with high module counts per string. Each microinverter produces a single-phase AC output; three-phase balancing across the 480V WYE system is achieved using a three-phase QD cable, which distributes single-phase outputs across phases at the array level. For 208/220V DELTA commercial systems, the separate IQ9N-3P-208 variant applies.

ITC domestic content bonus adder eligibility

The DOM-US variant is manufactured in the United States — PCBA, electrical components, and enclosure — to meet the domestic content eligibility requirements for the ITC Domestic Content Bonus Credit under IRS provisions. For commercial solar projects, the bonus adder can materially increase the effective Investment Tax Credit percentage when a qualifying share of domestically manufactured components is used across the system. Commercial projects typically involve larger capital outlays where the incremental ITC percentage carries greater absolute value than in residential deployments. The IQ9N-3P-277-A-DOM-US is available through A1 SolarStore as a path to meeting the inverter component of that threshold; full project qualification depends on the complete bill of materials and should be confirmed with a tax professional.

97.5% CEC efficiency and high-power module support

The IQ9's 97.5% CEC weighted efficiency is the highest published figure in the Enphase microinverter lineup to date, exceeding the IQ8X and IQ8HC's 96.5% CEC rating at 240V and matching the 97.5% figure across the full operating range. The 340–600W module compatibility window covers the current generation of commercial bifacial and high-density panels commonly specified in rooftop commercial projects, with a 28–45V MPPT range and 60V maximum DC input accommodating their operating voltage profiles.

Commercial installation and monitoring

PLC communication between units eliminates the need for separate data cabling runs across the commercial array, reducing installation labor and points of failure. The Enphase QD 4-pin AC connector system supports the three-phase QD cable required for 480V WYE configuration. System monitoring is delivered through the IQ Gateway Commercial Pro and the Enphase App, providing per-module production data, fault diagnostics, and remote visibility across the full commercial installation. The natural-convection cooling design — no fans, no moving parts — and Class II double-insulated NEMA Type 6 enclosure are rated for full rooftop outdoor exposure from -40°F to 149°F (-40°C to 65°C).

Why choose the Enphase IQ9 Commercial Microinverter DOM-US?

The Enphase IQ9 Commercial Microinverter DOM-US addresses two requirements that no earlier Enphase microinverter satisfies simultaneously: native 480V WYE three-phase commercial system compatibility at 427 VA peak output, and US-manufactured construction for ITC domestic content bonus adder eligibility on commercial projects. The 97.5% CEC weighted efficiency, 30-unit branch circuit density, 600W module compatibility ceiling, and 25-year warranty position it as a purpose-built commercial microinverter rather than a scaled residential unit. For commercial solar designers and installers building on the Enphase platform with domestic content requirements, the IQ9N-3P-277-A-DOM-US is available through A1 SolarStore — with the caveat that certification is pending and specifications remain preliminary as of the current datasheet revision.