NEC Article 690.4 in the 2023 edition establishes comprehensive general requirements for photovoltaic system installations across eight subsections:
Article 690 of the National Electrical Code governs photovoltaic electrical energy systems with major organizational changes in the 2023 edition. All definitions previously found in Section 690.2 have been relocated to Article 100 for consistency across the entire NEC. Section 690.4 now contains eight subsections addressing general requirements for both grid-tied and stand-alone systems.
The 2023 NEC introduces significant organizational improvements to Article 690. Code Making Panel 4 reorganized and renumbered multiple sections to enhance usability and compliance verification.
The most substantial change involves relocating all definitions from Article 690.2 to Article 100, standardizing terminology across the entire code. This modification ensures electrical terms apply consistently in all NEC sections rather than being specific to solar installations. Section 690.4 expanded from four subsections to eight, consolidating equipment listing requirements that were previously scattered across multiple sections. These standards reflect the rapid evolution of photovoltaic technology and emerging applications like floating solar installations.
The 2023 NEC relocated all PV-related definitions to Article 100, eliminating Section 690.2 entirely. Solar professionals must reference specialized terminology in Article 100 for consistent application across all code sections. Key definitions include:
Alternating-Current PV Module: A complete unit containing solar cells and an integrated micro-inverter that converts DC power to AC power when exposed to sunlight, listed specifically as an AC module.
Array: A mechanically integrated assembly of PV modules or panels including support structure, foundation, tracker, and components forming a DC power-producing unit.
Bipolar Photovoltaic Array: A PV array featuring two outputs, each with opposite polarity to a common reference point or center tap.
Building Integrated Photovoltaics: PV cells, devices, modules, or materials designed to integrate into a building's outer surface or structure, such as roof shingles that function as modules.
Direct Current Combiner: Equipment that combines two or more DC circuit inputs in parallel to provide one DC circuit output. This standardized term replaced industry variations like "source circuit combiners," "recombiners," "subcombiners," and "string combiner."
DC-to-DC Converter: A device installed in the PV source circuit or output circuit that provides output DC voltage and current at different values than the input. These components maximize individual module output and reduce losses from module output variances.
Interactive System: A PV system operating in parallel with utility power or other power sources through a utility-interactive inverter. Listed utility-interactive inverters automatically cease AC power export when utility power is lost and resume export after power restoration for at least five minutes.
Inverter: Equipment that converts DC power from the PV system to grid-interactive AC power. Grid-tied inverters synchronize AC output current with utility frequency, enabling unused PV power transfer to the utility grid.
Inverter Input Circuit: DC conductors between the battery and inverter in stand-alone systems, or between PV output circuits and an inverter in utility-interactive systems.
Inverter Output Circuit: AC circuit conductors from inverter output terminals supplying AC power to premises wiring, including conductors from AC modules.
Module: A PV unit engineered to generate DC power when exposed to sunlight using the photovoltaic effect to convert light into electrical current.
Monopole Subarray: A PV subarray with two conductors in the output circuit, one positive and one negative. Two monopole PV subarrays combine to form a bipolar PV array.
Multimode Inverter: An inverter with capabilities for both stand-alone and utility-interactive system operation.
PV Hazard Control Equipment (PVHCE): Equipment that reduces but does not eliminate shock hazards within a damaged PV array during firefighting procedures, meeting UL 3741 standards.
PV Hazard Control System (PVHCS): A system providing shock hazard control for firefighters through listed or field-labeled methods.
PV Output Circuit: Circuit conductors between the DC combiner and the DC input terminals of the inverter or DC disconnect.
PV Power Source: One or more arrays of PV modules generating DC voltage and current power.
PV Source Circuit: Circuit conductors between PV modules and DC combiner terminals, or inverter DC input terminals when no DC combiner is used. These circuits are commonly called "strings."
PV System Voltage: The direct current voltage of any PV source or output circuit. For multiwire installations, this represents the highest voltage between any two DC conductors.
Solar Cell: The fundamental building block of PV modules that generates DC power when exposed to sunlight.
Stand-Alone System: A PV system supplying power without interconnection to another electric power source.
Section 690.4(A) establishes that PV systems can supply power to buildings and other structures in addition to any other electrical supply system. This provision allows residential solar installations and commercial systems to operate alongside utility power, generators, wind systems, or other electrical sources while maintaining proper integration with existing electrical infrastructure.
The 2023 NEC significantly expanded Section 690.4(B) by consolidating equipment requirements from former Section 690.51. All equipment for PV systems must be listed or field labeled for photovoltaic applications:
Required Listed Equipment:
Circuit Identification Requirements: PV source circuits and PV output circuits must not be installed in the same raceway, cable tray, cable, outlet, junction, or pull boxes with non-PV system conductors unless separated by a partition. Conductors must be identified at all termination, connection, and splice points through separate color coding, marking tape, tagging, or other approved methods.
Grouping Requirements: Where conductors from more than one PV system occupy the same junction box or raceway with a removable cover, AC and DC conductors of each system must be grouped together with cable ties or similar means at intervals not exceeding 6 feet. Grouping is not required when circuit enters from a cable or raceway unique to that circuit.
Module Connection: Module connections must be arranged so removal of a module from a PV source circuit does not interrupt a grounded conductor connection to other PV source circuits.
Section 690.4(C) specifies that module connections must be configured to prevent interruption of the grounded conductor to other PV source circuits when a single module is removed. This requirement maintains system safety during maintenance operations.
PV source circuit and inverter output circuit conductors inside a building must be routed along building surfaces or within spaces specified by Section 690.4(D). These conductors cannot pass through more than necessary to reach the point of connection to systems contained in other wiring systems or equipment.
Section 690.4(E) requires that qualified persons perform all installation of equipment, associated wiring, and interconnections. According to Article 100, a qualified person possesses:
This requirement ensures installations meet safety standards and code compliance throughout the installation process.
The 2023 NEC introduces new Section 690.4(F) addressing floating photovoltaic systems (floatovoltaics). PV equipment floating on or attached to structures on bodies of water must be:
This subsection recognizes the growing deployment of solar installations on ponds, reservoirs, and other water bodies while establishing safety standards for these unique applications.
Section 690.4(G) establishes requirements for monopole subarrays in bipolar PV systems. When the sum of voltages of two monopole subarrays (without regard to polarity) exceeds conductor or equipment ratings, the subarrays must be physically separated, with separate raceways until connected to the inverter.
When multiple utility-interactive inverters are installed remotely from each other in a single building or structure, Section 690.4(H) requires directories at specific locations:
The directories must indicate the location of all DC and AC PV system disconnecting means throughout the structure. Directory requirements reference Section 705.10, which consolidated all placard and directory requirements for interconnected power systems. No directory is required when all disconnecting means are grouped at the service disconnecting means location.
The 2023 NEC recognizes advancing inverter technologies that provide enhanced functionality for photovoltaic systems. Multimode inverters combine capabilities of both stand-alone and utility-interactive systems, addressing operational needs during utility outages.
Standard utility-interactive inverters automatically cease operation when utility power fails due to automatic shutdown requirements protecting utility workers. This means buildings lose solar-generated power during outages despite having functional PV systems.
Multimode inverters operate as standard utility-interactive inverters under normal grid conditions. When utility power fails, the inverter automatically switches operational modes and signals an internal relay to disconnect from the utility source. This seamless transition maintains power to designated building loads while ensuring utility worker safety during line restoration work.
The 2023 NEC also introduced requirements for PV Hazard Control Systems (PVHCS) in Section 690.4(B), representing another significant technological advancement. These systems, certified to UL 3741 standards, provide shock hazard control for firefighters through methods beyond traditional module-level power electronics. PVHCS offers alternative compliance paths for rapid shutdown requirements while maintaining firefighter safety during emergency response operations.
Understanding the expanded Section 690.4 requirements in the 2023 NEC is essential for solar professionals navigating modern photovoltaic installations. The reorganization from four to eight subsections provides clearer guidance while addressing emerging technologies and compliant installations.
The consolidation of equipment listing requirements into Section 690.4(B) streamlines compliance verification for inspectors and installers. The addition of Section 690.4(F) for floating solar installations demonstrates the code's adaptation to innovative deployment methods. Requirements for qualified installation personnel, proper circuit identification, and circuit requirements ensure installations meet safety standards while maintaining grid safety and system reliability.
Understanding these general requirements positions solar professionals to navigate the remaining sections of Article 690, including rapid shutdown (690.12), grounding and bonding (690.43), and maximum voltage specifications (690.7) for systems exceeding 1000 VDC.
The 2023 NEC Article 690.4 represents a significant evolution in photovoltaic system requirements, expanding from four to eight subsections to address modern solar technologies and installation practices. The general requirements outlined in this section protect installers, property owners, and utility workers while ensuring solar systems integrate properly with existing electrical infrastructure.
Compliance with the 2023 Section 690.4 requires understanding the consolidated equipment listing requirements in 690.4(B), engaging qualified installation personnel per 690.4(E), and maintaining proper documentation through directories when multiple inverters are installed remotely per 690.4(H). The addition of requirements for floating PV equipment (690.4F) demonstrates the code's responsiveness to emerging installation methods.
The relocation of all definitions to Article 100 and the consolidation of equipment listing requirements from former Section 690.51 streamline code navigation and application. From PV hazard control systems meeting UL 3741 standards to circuit identification and grouping requirements, the 2023 solar technology standards reflect industry advancement while maintaining rigorous safety protocols.
Solar professionals who master these 2023 general requirements position themselves to deliver installations meeting current code standards while preparing for future technological developments. The expanded Section 690.4 provides the foundation for understanding rapid shutdown requirements (690.12), grounding specifications (690.43), and maximum voltage provisions (690.7) that together ensure safe, reliable photovoltaic systems. Solar Permit Solutions provides comprehensive design and engineering services ensuring full compliance with all 2023 NEC 690.4 requirements.
What equipment must be listed under NEC 2023 Section 690.4(B)?
The 2023 NEC consolidated all equipment listing requirements into Section 690.4(B). All equipment used in photovoltaic systems must require proper listing, including inverters, AC modules, DC combiners, DC-to-DC converters, charge controllers, PV rapid shutdown equipment (PVRSE), PV hazard control equipment (PVHCE), and PV hazard control systems (PVHCS). This expansion from the 2020 edition addresses modern safety equipment meeting UL 3741 standards for firefighter protection. Listed equipment ensures compliance with safety standards specific to solar installations and proper system performance per National Electrical Code requirements.
Who qualifies as a qualified person under NEC 2023 Section 690.4(E)?
Section 690.4(E) requires qualified persons to perform all PV system installations, wiring, and interconnections. Article 100 defines a qualified person as someone with skills and knowledge related to electrical equipment construction and operation, plus safety training to recognize and avoid electrical hazards. The 2023 edition emphasizes demonstrated competence through experience and training rather than requiring specific certifications, though jurisdictions may establish additional licensing requirements for PV system installation work.
When are directories required under Section 690.4(H) in the 2023 NEC?
The 2023 NEC relocated directory requirements to Section 690.4(H), which references Article 705.10 for placard and directory specifications. Directories are required when multiple utility-interactive inverters are installed remotely from each other within a single building or structure. The directories must be posted at each DC PV system disconnecting means, AC disconnecting means for AC modules and micro-inverters, and the service disconnecting means. These directories must show locations of all DC and AC disconnecting means throughout the structure. No directory is needed when all disconnecting means are grouped at the service equipment location.
What are the new requirements for floating PV systems in Section 690.4(F)?
Section 690.4(F) is completely new to the 2023 NEC, addressing photovoltaic equipment floating on or attached to structures on bodies of water (floatovoltaics). This equipment must be identified as suitable for the intended purpose and utilize wiring methods accommodating expected movement from water currents, wave action, and environmental conditions. The section recognizes unique challenges including mechanical stress, conductor insulation degradation, grounding continuity, and corrosion risks associated with water-based installations on ponds, reservoirs, and similar water bodies.
How did equipment identification requirements change in Section 690.4(B) for the 2023 NEC?
The 2023 edition significantly expanded Section 690.4(B) by consolidating requirements from former Section 690.51. Beyond basic equipment listing, the section now includes detailed circuit identification and grouping requirements. PV source circuits and output circuits must be separated from non-PV conductors unless partitioned, identified at all termination points through color coding or tagging, and grouped with cable ties at six-foot intervals when multiple systems share junction boxes or raceways. Module connections must be arranged to prevent grounded conductor interruption when removing individual modules for maintenance.
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