Code Change Summary: New language clarifies that when GFDI functionality is not built into an electronic power converter or related PV equipment, GFDI protection must cover the entire PV dc circuit and be listed for the specific equipment combination.

SME commentary: Section 690.41(B)(1) in the 2026 NEC^® has been revised to address a gap regarding how ground fault detection and interruption (GFDI) is provided in modern PV dc circuits. Many current PV systems use electronic power converters, PV rapid shutdown devices, dc-to-dc converters, and other equipment that may incorporate GFDI capabilities. However, these devices vary widely in how the GFDI function is implemented, whether the GFDI devices are integral to the equipment, and how the equipment is intended to be evaluated when used in combination with other PV components.

One Public Input (PI) by a Nationally Recognized Testing Laboratory provided substantiation explaining that inverters and other PV equipment with GFDI functionality must be evaluated with the specific devices that will operate alongside them in the same circuit. The PI noted that there have been field cases where certain PV components inadvertently masked ground fault signatures and prevented GFDI equipment from operating as intended. In response, the PI requested clearer NEC^® requirements stating that when the GFDI function is not integral to an electronic power converter, PVRSE, or PVHCE installed in the PV dc circuit, GFDI protection shall be provided for the entire circuit and be identified for the combination of the electronic power converter, PVRSE, PVHCE, and the GFDI device.

The CMP accepted this recommendation and added clarifying language to ensure that PV systems do not rely on partial GFDI coverage or assume that GFDI functionality exists simply because electronic equipment is present in the circuit. The revised text now specifies that GFDI devices or systems must detect ground faults in the PV dc circuits, including faults involving any functionally grounded conductors. It further requires GFDI protection to be installed for the entire circuit when the GFDI function is not included within the inverter or related equipment.

This clarity is especially important in systems where dc-to-dc converters, rapid shutdown devices, or other multi-function equipment share operational responsibilities. The revised code stresses the need for proper listing and identification of GFDI devices for the exact combination of equipment installed. This ensures that the GFDI function is neither bypassed nor blinded by other PV system components that may alter circuit behavior or affect how ground faults are sensed.

By reinforcing full-circuit GFDI coverage in specific configurations and requiring equipment combinations to be properly evaluated and identified, the 2026 NEC^® provides a more dependable basis for detecting PV ground faults across a wide range of current system designs. These changes help ensure that modern PV equipment operates together as intended, giving inspectors and installers clearer expectations when assembling or evaluating PV dc circuits.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2026 NEC^® edition of NFPA 70.

2023 Code Language:

690.41(B)(1) Ground-Fault Detection. The GFDI device or system shall detect ground fault(s) in the PV system dc circuits, including any functionally grounded conductors, and be listed for providing GFDI protection. For dc-to-dc converters not listed as providing GFDI protection, where required, listed GFDI protection equipment identified for the combination of the dc-to-dc converter and the GFDI device shall be installed to protect the circuit.

2026 Code Language:

690.41(B)(1) Ground-Fault Detection. GFDI devices or systems shall detect ground faults in the PV system dc circuits, including any functionally grounded conductors, and be listed for providing GFDI protection. Where the GFDI function is not integral to an electronic power converter, PVRSE, or PVHCE installed in the PV dc circuit, GFDI protection shall be provided for the entire circuit and be identified for the combination of the electronic power converter, PVRSE, PVHCE, and the GFDI device.