Last Updated: 2026-09-30
This article is part of the Print Pro AZ NEC 2026 solar labeling series. Start with the pillar guide: NEC 2026 Solar Labeling Changes Installers Must Know.
Last Updated: April 23, 2026
NEC 2026 Section 690.9(D) requires all overcurrent protection devices in photovoltaic system DC circuits to be marked "Photovoltaic" or "PV" directly on the device. This is a new requirement, previously, solar OCPDs only needed to be listed for PV use. Inspectors now have explicit grounds to reject any unmarked DC breaker or fuse in a PV circuit.
Your solar DC circuit passed every other inspection checkpoint, conductors properly sized, combiner box neat, rapid shutdown wired correctly, and then the AHJ called out your breakers. They weren't marked "Photovoltaic."
Under NEC 2026, that's a code violation. The NEC 690.9 PV marking requirement, added in Section 690.9(D), closes a loophole installers and inspectors both knew existed: a breaker could be listed for DC use without being specifically rated for photovoltaic applications. The new wording eliminates that ambiguity. Every OCPD in your PV system's DC circuits must now carry the marking, on the device, not just the box.
This guide walks through exactly what the requirement covers, why it matters, and how to confirm you're using the right equipment before you schedule inspection.
What Does NEC 2026 Section 690.9(D) Actually Require?
NEC 2026 Section 690.9(D) requires that any overcurrent protective device (OCPD) used in a PV system DC circuit be marked "Photovoltaic" or "PV." The marking must appear on the device itself, the breaker or fuse, not solely on the manufacturer's packaging or datasheet.
The key word is marked. This is distinct from the listing requirement that's been in place since earlier NEC editions. A device can be listed for DC use and still fail this new requirement if it doesn't carry the explicit "Photovoltaic" or "PV" label on the equipment.
What this covers:
- DC string-level fuses in combiner boxes
- DC circuit breakers protecting source circuits and output circuits
- Any OCPD placed in a DC PV circuit regardless of system size
Code Reference: National Electrical Code 2026, Article 690, Section 690.9(D), Marking. OCPDs used in PV system dc circuits shall be marked Photovoltaic or PV.
AHJs (Authorities Having Jurisdiction) vary by city in how aggressively they enforce new code changes, always confirm locally. But with the specific language now written into 690.9(D), expect this to become a standard checklist item across most jurisdictions adopting NEC 2026.
Why Solar DC Circuits Need PV-Specific Breakers and Fuses
The reason this marking matters comes down to physics: DC current behaves differently than AC, and solar systems impose conditions that standard DC breakers aren't designed to handle.
Standard AC breakers interrupt current at the natural zero-crossing point, the moment in each cycle where current briefly drops to zero. DC current has no zero-crossing. It flows continuously, which means any arc created when a breaker opens must be forcibly quenched rather than extinguished by the current naturally dropping away.
PV-rated overcurrent devices are built for this. They include:
- Magnetic blowout coils to physically push the arc into quenching chambers
- Extended arc chutes designed for high-voltage DC interruption
- Larger contact gaps and arc runners rated for the thermal stress of DC fault interruption
The consequences of using the wrong device are severe. An undersized or improperly rated breaker can fail to interrupt a DC fault, sustain an arc that burns through the enclosure, and ignite a fire. A 1000V DC arc has far more destructive energy than a 120V AC arc, it can bridge larger air gaps and sustain itself across carbonized insulation that would otherwise be non-conductive.
PV-specific fuses typically carry a gPV rating per UL 2579, purpose-designed for photovoltaic circuit protection. For breakers, look for explicit "Photovoltaic" or "PV" on the label and verify DC voltage ratings match your system's maximum voltage per NEC 690.7. EC&M's overview of NEC guidelines for photovoltaic systems covers the broader Article 690 equipment listing framework if you need additional context.
What Changed From NEC 2023 to NEC 2026 for Solar OCPDs?
The 2023 NEC required OCPDs in PV source and output circuits to be listed for use in PV systems. The 2026 NEC adds a marking requirement on top of that listing requirement.
This is an important distinction. Here's how the two editions compare:
| Code Requirement | NEC 2023 | NEC 2026 |
|---|---|---|
| OCPD must be listed for PV use | ✓ Required | ✓ Still required |
| OCPD must be marked "Photovoltaic" or "PV" | Not explicitly required | ✓ NEW, 690.9(D) |
| Standard DC-rated breaker acceptable if listed | Possible gray area | Not acceptable without PV marking |
The practical impact: if you've been using a DC-rated breaker that passed listing requirements under NEC 2023 but doesn't carry the "Photovoltaic" marking, that same device may now fail inspection in an AHJ that has adopted NEC 2026.
Check the device nameplate, not just the spec sheet. If it says "DC" without "Photovoltaic" or "PV," it's not compliant under 690.9(D).
How Do You Verify an OCPD Is Marked 'Photovoltaic'?
Check the nameplate on the device itself. The marking must appear on the equipment, this is what an inspector will verify in the field, not a manufacturer data sheet you hand them.
Step-by-step verification process:
- Remove the breaker or fuse from packaging
- Look at the face or body of the device for the word "Photovoltaic" or the abbreviation "PV"
- Confirm the DC voltage rating equals or exceeds your system's NEC 690.7 maximum voltage
- Confirm the interrupting rating (AIC) covers your system's available fault current
- Verify the ampere rating matches your 690.9(B) calculation (Isc × 1.25, minimum)
For fuses, the gPV designation is the clearest indicator. For breakers, manufacturers such as Square D, Eaton, Siemens, and others produce breakers with explicit "PV" or "Photovoltaic" markings for solar applications.
What doesn't count: "Listed for DC use," "DC-rated," or "suitable for DC circuits" without the specific "Photovoltaic" or "PV" designation doesn't satisfy 690.9(D).
Practical tip: Pull the breaker before you schedule inspection and photograph the nameplate. If the marking isn't visible in the photo, it's not there.
Where Is the 690.9(D) Marking Required in Your System?
Section 690.9(D) applies to all OCPDs in PV system DC circuits, which covers more equipment than just the string-level protection in your combiner box.
Locations where you'll find OCPDs that must carry the marking:
- PV source circuits, string-level fuses or breakers protecting individual strings
- PV output circuits, the circuit from combiner box to inverter
- DC combiner boxes, any fuse holders or breaker positions inside
- Battery charge controller circuits (where applicable in hybrid and storage systems)
The marking requirement does NOT apply to AC-side overcurrent protection, only to DC circuits in the photovoltaic system.
For systems using microinverters or DC optimizers where there are no traditional DC source or output circuits, confirm with your AHJ whether 690.9(D) applies. Systems where inverters are directly connected at the module level operate differently than string inverter systems.
What We See in the Field: A Solar OCPD Inspection Failure
Here's a scenario that's common in the Phoenix market and increasingly common everywhere NEC 2026 is being adopted.
An installer completes a residential solar install, clean work, correct rapid shutdown, voltage labels on the combiner box. Inspection goes smoothly until the AHJ opens the combiner and sees DC breakers without any "Photovoltaic" marking. The breakers were listed for DC applications and had been used on dozens of jobs under NEC 2023 without issue.
Under NEC 2026, that's a correction notice. The installer has to pull permits again, replace the breakers with PV-marked equivalents, and reschedule inspection. Two extra weeks. Real rework cost.
At Print Pro AZ, we supply the labels, but we also talk to installers every week about what AHJs are calling out. The single most preventable source of rework we hear about is equipment selection that was compliant under a previous code edition but fails under the adopted code. Know which edition your AHJ is enforcing before you spec your OCPDs.
Related reading: Rapid Shutdown Labels: NEC 2017 vs 2020 vs 2023 Requirements
Frequently Asked Questions
Does every solar system need OCPDs marked 'Photovoltaic' under NEC 2026?
NEC 2026 Section 690.9(D) applies to OCPDs used in PV system DC circuits. Not every solar system requires OCPDs in every circuit, per NEC 690.9(A), a DC source circuit doesn't require an OCPD if there are no parallel current sources that could backfeed excess current into that string. But where OCPDs are required and installed, 690.9(D) mandates the "Photovoltaic" or "PV" marking.
Can I use a standard DC circuit breaker if it's listed for the correct voltage and amperage?
No. Under NEC 2026, DC ratings alone are insufficient. Section 690.9(D) requires the device to be marked "Photovoltaic" or "PV", a requirement specific to PV applications that goes beyond general DC listing. A breaker listed for 600V DC use in industrial applications does not satisfy 690.9(D) if it lacks the photovoltaic marking.
Does NEC 2026 apply to my state right now?
NEC adoption is state-by-state and often city-by-city. As of April 2026, most states are still operating under NEC 2023 or earlier editions. However, some AHJs adopt new editions ahead of statewide mandates. Always confirm which edition your local AHJ is enforcing before permit submission. Call the building department directly, don't assume.
What's the difference between a gPV fuse and a standard DC fuse?
A gPV-rated fuse is specifically designed for photovoltaic applications per UL 2579 and IEC 60269-6. These fuses handle the characteristic current behavior of solar strings, including edge-of-cloud irradiance spikes that can temporarily exceed module Isc ratings. Standard DC fuses are not rated for the cyclic loading and current characteristics of PV source circuits.
Where can I confirm the right labels for my solar install in addition to the OCPD?
The other required field-applied labels, including the DC disconnect label per 690.53, rapid shutdown labels per 690.12, and PV power source conductor labels per 690.31, are all part of your NEC compliance package. Print Pro AZ's residential solar label bundle covers the field-applied labels required for most residential grid-tied installs.
Conclusion: The Photovoltaic Marking Is Now Non-Negotiable
Three things to take away from NEC 2026 Section 690.9(D):
- "Listed for DC use" is no longer enough, the device must be marked "Photovoltaic" or "PV" on the nameplate.
- This applies to all OCPDs in DC PV circuits, source circuits, output circuits, and combiner boxes.
- Check the device, not the packaging, inspectors verify the marking on the equipment itself.
Getting your equipment selection right before you pull the permit saves you the cost of a correction notice and a return trip. If you're building out your NEC label package for your next solar install, shop our NEC-compliant solar label packs, we stock the field-applied labels for residential and commercial PV installs, made to spec at our Phoenix facility.
Questions about which labels your job requires? Call Brent: (602) 649-5305
Brent Hanke | Print Pro AZ | (602) 649-5305 | b.hanke@printproaz.com Brent Hanke is the founder of Print Pro AZ, supplying NEC-compliant labels to contractors across the country.
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