Key takeaways
- The labels sheet is one of six sheets in a residential plan set, and its contents depend on the code cycle your AHJ has adopted, not the newest edition published.
- The rapid shutdown building label moved between cycles. NEC 2017 and NEC 2020 put it at 690.56(C). NEC 2023 relocated the same marking into 690.12(D), inside the rapid shutdown section itself.
- NEC 2023 690.31(D)(2) requires DC circuits inside a building to carry white-on-red markings at least 3/8 inch tall, repeated at least every 10 feet. In the 2017 cycle that rule sat at 690.31(G).
- NEC 110.21(B) is why hand-written and inkjet labels fail. Hazard labels cannot be hand written, and have to survive the environment they are installed in.
Solar labels and placards are the permanent markings a PV system carries so an electrician, an inspector or a firefighter can identify every power source and shut it down safely. Under NEC 2023 they come from 690.7(D), 690.12(D), 690.13(B), 690.31(D), 705.10, Article 706, 110.16 and 110.21(B) — and several of those sections held different numbers one code cycle ago.
Why does the labels sheet get corrected so often?
Because it is the cheapest thing on the drawing set to check. Verifying conductor ampacity means working through a calculation. Verifying the labels sheet means reading it against the adopted code cycle — a wrong section number, a missing placard or a label quoted from the wrong edition is visible in ninety seconds, and comes back as a correction.
Our solar plan sets carry the labels sheet as a drawn, cycle-specific deliverable rather than a generic label-kit callout, because a generic kit is what produces the mismatch. For the wider picture, which NEC article governs a solar plan set maps 690, 705, 706 and 710 across the package. This piece stays on the labels sheet.
Field inspection compounds it. NREL’s introduction to residential rooftop PV field inspections names “Are PV system markings, labels, and signs installed according to the approved plan?” as a major problem area. The sheet gets checked twice — on paper, then on the wall — and if the two disagree, the inspection fails even though the plan set passed.
Which NEC section requires each label?
Eight sections do most of the work on a residential or small commercial labels sheet. Three sit in different places depending on the adopted cycle — the most common citation error we see on incoming drawings.
| What gets marked | NEC 2023 section | Where the same rule sat earlier |
|---|---|---|
| PV system disconnecting means | 690.13(B) | 690.13(B) — unchanged |
| Highest maximum DC voltage | 690.7(D) | Added in the 2023 cycle |
| Rapid shutdown, building label | 690.12(D) | 690.56(C) in 2017 and 2020 |
| PV DC circuits on or in a building | 690.31(D)(2) | 690.31(G)(3), (G)(4) in 2017; 690.31(D) in 2020 |
| Power sources at service equipment | 705.10 | 705.10 |
| Energy storage disconnecting means | 706.15 | Article 706 |
| Arc-flash hazard, non-dwelling equipment | 110.16(A) and (B) | Same, but a 1200 A threshold in (B) |
| How every hazard label must be made | 110.21(B) | 110.21(B) — unchanged |
Most did not change substantively between 2017 and 2023 — what changed is where they live, and citing the right requirement at the wrong address still draws a correction. Disconnect placement is a separate question from disconnect marking, covered in PV disconnect placement across code cycles.
What does the PV system disconnect have to say?
NEC 2023 690.13(B) requires each PV system disconnecting means to plainly indicate whether it is in the open (off) or closed (on) position, and to be permanently marked “PV SYSTEM DISCONNECT” or equivalent. Additional markings are permitted where the configuration calls for them.
A second marking in the same subsection gets missed constantly. Where the line and load terminals can be energized in the open position — the normal condition for a PV disconnect, since the array is still making voltage — the disconnect needs an additional warning that terminals on both sides may be energized when the switch is open.
The 2023 cycle also added 690.7(D), Marking DC PV Circuits, requiring the installer to provide the system’s highest maximum DC voltage at one of the locations that section lists. That is not a nameplate value — it comes out of the cold-temperature Voc calculation, which is why we treat string sizing and the labels sheet as the same job.
Did the rapid shutdown label move between code cycles?
Yes, and it is the citation most likely to be wrong on a plan set. Under NEC 2017 and NEC 2020, the building label for a PV system equipped with rapid shutdown sat at 690.56(C). NEC 2023 removed the previous contents of 690.12(D) and replaced them with that marking language, keeping the old section title — so in the 2023 cycle the same label is required by 690.12(D).
Solar Power World’s summary of the 2023 code changes to rapid shutdown puts it plainly: the marking requirements from 690.56(C) were moved to 690.12(D), with minor changes to the requirements themselves.
Section 690.56 still exists in the 2023 NEC, titled Identification of Power Sources, and points to 705.10 — so a 2023-cycle set citing 690.56(C) for the rapid shutdown label points at a section that no longer contains it.
Under NEC 2023 690.12(D) the label is a permanent marking at the service equipment or another approved readily visible location, reading:
SOLAR PV SYSTEM IS EQUIPPED WITH RAPID SHUTDOWN. TURN RAPID SHUTDOWN SWITCH TO THE “OFF” POSITION TO SHUT DOWN PV SYSTEM AND REDUCE SHOCK HAZARD IN ARRAY.
It includes a simple diagram of a building with a roof, the title is capitalized at a minimum letter height of 3/8 inch, and all of it has to be legible against its background. The initiation device itself also has to be labelled, indicating off or on.
How do DC circuits inside a building get marked?
NEC 2023 690.31(D)(2) requires PV system DC circuits run on or in a building to be marked “PHOTOVOLTAIC POWER SOURCE” or “SOLAR PV DC CIRCUIT.” All letters capitalized, minimum height 9.5 mm (3/8 inch), white lettering on a red background.
The placement rules are what gets enforced. The marking has to appear on every section of the wiring system separated by enclosures, walls, partitions, ceilings or floors, and spacing cannot exceed 3 m (10 ft). On an attic run from roof penetration to garage inverter that is not one label — it is a label at each side of every penetration, at each junction box and conduit body, and every ten feet between.
This is one of the requirements that moved. In the 2017 cycle the same rule lived at 690.31(G): (G)(3) covered which wiring methods and enclosures had to be marked, (G)(4) covered how and where. The 2017 wording also required “WARNING: PHOTOVOLTAIC POWER SOURCE”; the 2020 and 2023 cycles accept “PHOTOVOLTAIC POWER SOURCE” or “SOLAR PV DC CIRCUIT.”
What has to be marked at the point of interconnection?
NEC 2023 705.10 requires permanent plaques, labels or directories at each service equipment location, or at an approved readily visible location. Three things go on it: the location of each power source disconnecting means for the building, the emergency telephone numbers of any off-site entities servicing the power source systems, and the wording “CAUTION: MULTIPLE SOURCES OF POWER.”
705.10 also states the marking has to comply with 110.21(B) — the durability rule below, and the reason a printed sheet taped inside the panel door does not satisfy it. The directory is the piece that gets skipped. A “CAUTION: MULTIPLE SOURCES OF POWER” sticker on the meter is not a directory. It has to tell someone standing at the service equipment where every disconnecting means is — PV, storage, generator, anything else. On a house with a main panel, a subpanel, an exterior AC disconnect and a battery, that is four locations to name.
In the 2017 cycle, Article 690 carried its own identification-of-power-sources language at 690.56 alongside 705.10; in the 2023 cycle 690.56 defers to 705.10, so 705.10 is the citation for the sheet. Getting this wrong is one of the permitting nuances that catch installers out.
What labels does energy storage add?
A battery adds at least two markings. Under NEC 2023 706.15, the energy storage disconnecting means has to plainly indicate whether it is open or closed and be marked to identify it as the ESS disconnect, and where the terminals can be energized in the open position it needs the same both-sides-energized warning the PV disconnect carries.
Article 706 also requires field marking of the battery disconnecting means in non-dwelling installations: nominal battery voltage, available fault current derived from the battery system, an arc-flash label per acceptable industry practice, and the date the calculation was performed — which a later service change invalidates.
Arc flash is where commercial and residential separate. NEC 2023 110.16(A) applies in other than dwelling units: switchboards, switchgear, panelboards, industrial control panels, meter socket enclosures and motor control centers likely to require servicing while energized must be field- or factory-marked for arc-flash hazards. 110.16(B) applies to service equipment rated 1000 amperes or more and requires a label showing the arc flash boundary plus one of available incident energy, arc flash PPE category, minimum arc rating of clothing, or site-specific PPE level, with the date.
Note the threshold. In the 2017 and 2020 cycles 110.16(B) applied at 1200 A; 2023 lowered it to 1000 A and changed the required content. On commercial solar PV designs at 1000 A or above, that is a label that did not exist two cycles ago — and the study behind it is the same scope conversation as engineering stamps.
Why does a hand-written label fail?
NEC 110.21(B) governs how every hazard label required by the Code has to be made, in three parts. The marking has to adequately warn of the hazard using effective words, colors or symbols. The label has to be permanently affixed to the equipment or wiring method and shall not be hand written. And it has to be of sufficient durability to withstand the environment involved.
One narrow exception: portions of a label that are variable or subject to change may be hand written if legible. An available fault current figure and a calculation date qualify. “PV SYSTEM DISCONNECT” in marker pen does not.
The durability clause is what kills inkjet labels on a rooftop. A label printed on paper stock survives plan review and fails an inspection eighteen months later, faded to blank. Rooftop and exterior locations mean UV, heat cycling and weather, and 110.21(B)(3) is what an inspector cites when a label is unreadable.
The informational note to 110.21(B)(1) points at ANSI Z535.4, Product Safety Signs and Labels, which is where the signal words come from. Z535.4 sets the hierarchy: DANGER in red for a hazard that will cause death or serious injury, WARNING in orange for one that could, CAUTION in yellow for one that may cause minor or moderate injury. That is why “CAUTION: MULTIPLE SOURCES OF POWER” is a caution and not a danger — the signal word is a severity classification, not a design choice. OSHA’s sign and tag standard, 29 CFR 1910.145, uses the same three and incorporates the ANSI Z535 colour standard by reference.
Specifying “engraved or UV-stable reflective label, per ANSI Z535.4” on the sheet costs nothing and closes the argument early — one more for the list of what to avoid when making solar plans.
Worked example: a label schedule for one system at one cycle
A 9.6 kW roof mount with module-level rapid shutdown, a 7.6 kW hybrid inverter, a 13.5 kWh battery, a 200 A residential service, and a 34 ft DC conduit run from roof penetration through attic to garage. Jurisdiction: Oregon, where the Oregon Electrical Specialty Code is based on the 2023 NEC and took effect 1 October 2023. The schedule:
- PV SYSTEM DISCONNECT — on the PV disconnecting means, with open/closed indication. NEC 2023 690.13(B).
- Both-sides-energized warning — same disconnect, warning that line and load terminals may be energized in the open position. NEC 2023 690.13(B).
- Maximum DC voltage marking — from the cold-temperature Voc calculation. NEC 2023 690.7(D).
- Rapid shutdown building label — at the service equipment, roof diagram included, title capitalized at 3/8 inch minimum. NEC 2023 690.12(D).
- Rapid shutdown initiation device label — at the initiation device, indicating off or on. NEC 2023 690.12(D).
- PHOTOVOLTAIC POWER SOURCE or SOLAR PV DC CIRCUIT — white on red, 3/8 inch capitals, both sides of the roof penetration, at each junction box and conduit body, and at 10 ft maximum spacing. On 34 ft that is four labels minimum before fittings. NEC 2023 690.31(D)(2).
- CAUTION: MULTIPLE SOURCES OF POWER plaque and directory — at the service equipment, naming the PV and ESS disconnect locations plus the emergency service number. NEC 2023 705.10.
- ESS disconnect marking — identifying the energy storage disconnecting means, open/closed indication. NEC 2023 706.15.
No arc-flash label here: 110.16(A) applies in other than dwelling units, and a 200 A residential service is neither a non-dwelling occupancy nor at the 1000 A threshold in 110.16(B).
Move it to a 2017-cycle AHJ and item 4 becomes 690.56(C), item 6 becomes 690.31(G)(3) and (G)(4) with “WARNING:” in front, and item 3 comes off entirely. Same system, different sheet. Run the package through a pre-submittal check against the adopted cycle first. For Oregon work, our Oregon solar plan sets are drawn to the state’s cycle by default.
Which code cycle does your AHJ actually enforce?
The one it has adopted — frequently not the newest one published. NFPA publishes NEC adoption maps by state showing which edition is enforced where, and the country is spread across multiple editions at any time. Some states adopt statewide, some leave it to the municipality, and local amendments modify individual sections.
This matters more on the labels sheet than most, because the requirements moved. A 2017-cycle jurisdiction wants 690.56(C) and 690.31(G); a 2020-cycle jurisdiction, 690.56(C) and 690.31(D); a 2023-cycle jurisdiction, 690.12(D) and 690.31(D)(2). Each is correct in its own jurisdiction and wrong in the other two.
Confirm the cycle with the AHJ before the sheet is drawn, not after the correction arrives — then put the edition and any local amendments in the general notes on the cover sheet, so the plan checker can see which book you worked from. That one line removes a whole category of correction.
FAQ
What labels are required on a solar PV system?
Under NEC 2023: the PV disconnect marking and its energized-terminals warning (690.13(B)), the maximum DC voltage marking (690.7(D)), the rapid shutdown building and initiation device labels (690.12(D)), DC circuit markings inside the building (690.31(D)(2)), and the multiple-sources plaque and directory (705.10). Storage adds ESS disconnect marking under Article 706; non-dwelling equipment adds arc-flash marking under 110.16.
Which NEC section requires the rapid shutdown label?
It depends on the cycle. NEC 2017 and NEC 2020 put the building rapid shutdown label at 690.56(C); NEC 2023 moved the same marking into 690.12(D). Section 690.56 still exists in 2023, but it is titled Identification of Power Sources and refers to 705.10, so citing 690.56(C) on a 2023-cycle set points at the wrong section.
Can solar labels be hand written?
No. NEC 110.21(B)(2) requires hazard labels to be permanently affixed and states they shall not be hand written. The only exception covers variable portions — an available fault current value or a calculation date — which may be hand written if legible.
What labels does a battery add to the plan set?
NEC 2023 706.15 requires the energy storage disconnecting means to indicate open or closed and be marked as the ESS disconnect, with a both-sides-energized warning where terminals can be live in the open position. Article 706 also requires field marking of the battery disconnecting means in non-dwelling installations: nominal battery voltage, available fault current, an arc-flash label, and the calculation date.
Does the labels sheet change if my AHJ is still on NEC 2017?
Yes. The rapid shutdown label is cited at 690.56(C) rather than 690.12(D), DC circuit marking at 690.31(G)(3) and (G)(4) with “WARNING: PHOTOVOLTAIC POWER SOURCE” wording, and 690.7(D) does not apply — it was added in the 2023 cycle.
Order a plan set with the labels sheet drawn to your cycle
Most drafting delays are not drafting. They are the second submittal, three weeks after the first, over something a plan checker read in ninety seconds.
Avila Solar Drafting builds permit-ready solar plan sets in 2–3 business days, or 1–2 business days for Fast Roof, with the labels sheet drawn to the cycle your AHJ has actually adopted — backed by our guarantee of accurate solar plan sets and free AHJ and utility revisions, plus 3 months of free change orders from data submission.
Commercial, large storage, or a jurisdiction with local amendments you are unsure about? Call 971-410-0655 and we will scope it directly.
