NEC 2023 690.12 rapid shutdown uses the same numbers NEC 2017 set: a 1-foot array boundary, 30 volts outside it and 80 volts inside it, both within 30 seconds. The physics hasn’t moved since 2017 — what changed is where the marking rule lives, plus a new exception for carports and other detached structures. If your solar plan sets still cite 2017 language, the disconnect design is probably fine. The citation, and the exceptions you’re leaving unclaimed, aren’t.
Key takeaways
- NEC 2023 690.12 rapid shutdown uses the same limits NEC 2017 introduced: a 1-foot array boundary, 30 volts outside it and 80 volts inside it, both within 30 seconds.
- What actually changed between the two cycles: NEC 2023 exempts non-enclosed detached structures — carports, parking shade structures, solar trellises — from 690.12 entirely, and moved the rapid shutdown marking requirement from 690.56(C) to 690.12(D).
- General PV system disconnect placement (690.13) follows the same test in both cycles — the disconnect has to isolate every component that converts solar energy into electricity without disabling anything downstream.
- Sections 690.16 and 690.17 don’t exist anymore. They were folded into 690.13 and 690.15 before the 2017 cycle even shipped — if a checklist still cites them, it predates NEC 2017 itself.
- Cite the cycle every time: “NEC 2023 690.12,” not bare “690.12.” Some AHJs are still enforcing editions from 2014 or 2017, and the exceptions available to them are different.
Where does a PV system disconnect actually go?
A PV system disconnect has to isolate every component that converts solar energy into electricity, without disabling anything downstream of it. That test comes from NEC Article 100’s definition of a PV system, and it hasn’t moved between the 2017 and 2023 cycles — only where you find the rule has moved, from the multi-section 690.13/690.15 split still in use under NEC 2017 to a single consolidated PV system disconnecting means provision at NEC 2023 690.13.
Work it from the single-line diagram, not a template. A grid-direct interactive system has two acceptable disconnect locations: an external switch between the inverter and the electrical panel, or the panel’s own breaker, depending on what the AHJ allows. The inverter’s integrated DC disconnect doesn’t count on its own — the AC side of the inverter is still connected to the utility load even with the DC side opened, so it isn’t isolating the full system the code definition requires.
Multimode systems change the answer. A DC-coupled multimode inverter needs its disconnect between the array and the inverter, plus a separate interactive disconnect between the inverter and the grid, so the energy storage system can keep serving backup loads without exporting into a de-energized grid. An AC-coupled multimode system needs an energy storage disconnect between the inverter and the battery, and an interactive disconnect between the inverter and the grid connection. The rating on every one of those disconnects has to match what the array can actually put out, not a rule of thumb — that’s a string sizing calculation, not a disconnect one, but the two feed each other on the same sheet.
What actually changed in NEC 2023 690.12 rapid shutdown?
Nothing in the core voltage, time, or distance limits. NEC 2017 was the cycle that introduced the modern rapid shutdown array boundary — 1 foot from the array in all directions — along with the split that still governs the requirement: controlled conductors outside the boundary must drop to 30 volts within 30 seconds of initiation, and conductors inside the boundary must drop to 80 volts in the same window. That inside-the-array limit is what effectively requires module-level equipment on most string-inverter systems, and NEC 2023 carries the same three numbers forward unchanged.
Per UL Solutions, the rapid shutdown requirements in the 2014 and 2017 NEC cycles are what drove the development of ANSI/CAN/UL 3741, the Standard for Photovoltaic Hazard Control, published in December 2020. A PV hazard control system listed to UL 3741 is now the second compliance path under NEC 2023 690.12 — install listed rapid shutdown equipment at the module or string level, or install a system evaluated and listed as a complete PVHCS. Either way, the equipment has to be listed for the application; a generic string inverter with no rapid shutdown feature satisfies neither path. For how 690.12 sits alongside the rest of Article 690 and the articles that touch storage and interconnection, see our NEC article map for a solar plan set.
The numbers didn’t move — the paperwork did
The rapid shutdown marking requirement is what actually relocated between cycles. Under NEC 2017 and NEC 2020, that marking language sits at 690.56(C). NEC 2023 consolidated it into a new 690.12(D), inside the rapid shutdown section itself instead of a separate marking article. A plan set that references 690.56(C) for the rapid shutdown label isn’t wrong about the requirement — it’s citing the 2017/2020 address for a rule that moved.
The initiation device has its own placement rule, and this is one reviewers check on sight. Per NREL’s residential rooftop PV inspection guidance, the rapid shutdown initiation device must be labeled on the plans, and it has to be either the service disconnecting means, the PV system disconnecting means, or a readily accessible switch that plainly indicates whether it’s in the “off” or “on” position. NEC 2023 690.12(C) adds the specific requirement that at one- and two-family dwellings, that device has to sit outside, at a location that’s readily accessible — a site plan detail as much as a one-line item. Getting the citation and the device location right the first time is exactly the kind of detail a stamped design review catches before submittal — see what we cover under engineering stamps when a project needs one.
Are carports and trellises exempt from rapid shutdown?
Under NEC 2023, yes — if the structure is non-enclosed. The 2023 cycle added an exception to 690.12 for non-enclosed detached structures, specifically naming carports, parking shade structures, and solar trellises, on the reasoning that firefighters don’t work those roofs the way they do a dwelling. A carport array that qualifies doesn’t need rapid shutdown equipment at all under the current cycle.
Under NEC 2017, no exception exists. That same carport array needs full 690.12 compliance — the 1-foot boundary, the 30-volt and 80-volt limits, and a labeled, correctly placed initiation device — regardless of the structure type. The exception is a 2023-cycle addition, not a clarification of something 2017 already implied. Whether it applies to your project depends entirely on which edition your AHJ has adopted and how that AHJ classifies the structure, not on the hardware you specify.
Structure classification is where this gets tested in practice. “Non-enclosed” is doing real work in the exception’s language — a carport with solid siding on more than one side, or a trellis built out with any kind of wall panel, may not read as non-enclosed to a reviewer even if it reads that way to the installer. Don’t design the exception in without confirming both the adopted cycle and the AHJ’s read on the structure. A ground-mount array on open racking is the same story: it isn’t automatically a “detached structure” for 690.12 purposes just because it’s off the roof, and ground-mount plan sets still get the full rapid shutdown treatment unless the specific structure qualifies under the 2023 exception language.
Why this matters if your AHJ hasn’t adopted NEC 2023 yet
Code adoption doesn’t move on a single national clock. Oregon’s Building Codes Division adopted the 2023 NEC as the base for the Oregon Electrical Specialty Code effective October 1, 2023 — Avila’s home state is on the current cycle. The District of Columbia’s Department of Buildings, by contrast, states that its 2017 Construction Codes carry the 2014 National Electrical Code. A plan set drawn to NEC 2023 690.12’s carport exception and submitted to a jurisdiction still enforcing 2014 or 2017 language will get flagged for a requirement the newer cycle no longer imposes on that structure.
This is precisely the failure mode behind a lot of solar permit rejections that read like a design error but are actually an edition mismatch — the reviewer is applying a different cycle than the drawing was built to. AHJ-to-AHJ variation on rapid shutdown enforcement is common enough that it’s worth checking before you assume an exception applies; see solar permitting nuances for more of the category. The fix isn’t guessing — it’s naming the cycle on the drawing and confirming the AHJ’s adopted edition before the exception gets designed in or out.
Worked example: a solar carport at two code cycles
An installer submits the same 24-module solar carport design for two jobs — one in a jurisdiction enforcing NEC 2017, one enforcing NEC 2023.
Under NEC 2017 690.12, both projects need full rapid shutdown compliance: module-level equipment limiting conductors outside the 1-foot array boundary to 30 volts within 30 seconds, conductors inside the boundary to 80 volts in the same window, and a labeled, readily accessible initiation device.
Under NEC 2023 690.12, the carport qualifies for the non-enclosed detached structure exception — no rapid shutdown equipment required at all. Same array, same racking, same modules. The 2017-cycle job still needs full module-level compliance; the 2023-cycle job doesn’t need rapid shutdown equipment on the carport circuit. Nothing about the design changed. The AHJ’s adopted cycle decided whether the carport needed rapid shutdown in the first place — which is also why a DC solar plan set and an Oregon one don’t always draw the same disconnect scheme for what looks like an identical array. For how that plays out on a full DC submittal, see getting DC plan sets right the first time.
FAQ
Where can you place a PV system disconnect?
Wherever it isolates every component that converts solar energy into electricity without disabling anything downstream — that test hasn’t changed between NEC 2017 and NEC 2023. For a grid-direct interactive system, that’s typically an external switch between the inverter and the electrical panel, or the panel’s own breaker if the AHJ allows it. Multimode systems with battery backup need additional disconnects specific to the storage and grid-interactive portions of the circuit.
What does NEC 2023 690.12 require for rapid shutdown?
NEC 2023 690.12 requires PV system conductors outside a 1-foot array boundary to be limited to 30 volts within 30 seconds of initiation, and conductors inside the boundary to 80 volts in the same window. The initiation device must be labeled and located per 690.12(C), and the required marking now sits at 690.12(D). A system using a PV hazard control system listed to UL 3741 can satisfy the requirement as a listed system instead of module-level equipment.
Did the NEC 2023 rapid shutdown limits change from NEC 2017?
No — the 1-foot boundary, the 30-volt and 80-volt limits, and the 30-second window are the same numbers NEC 2017 established. What changed is where the marking requirement is cited (690.56(C) under 2017/2020 versus 690.12(D) under 2023) and a new 2023 exception for non-enclosed detached structures like carports and trellises.
Are solar carports exempt from rapid shutdown under NEC 2023?
Yes, if the structure is non-enclosed. NEC 2023 690.12 added an exception for non-enclosed detached structures — carports, parking shade structures, and solar trellises — because firefighters don’t work those roofs. NEC 2017 has no equivalent exception, so the same carport array needs full rapid shutdown compliance in a jurisdiction still enforcing that cycle.
Do NEC 690.16 and 690.17 still apply to PV disconnects?
No. Sections 690.16 and 690.17 were consolidated into 690.13 and 690.15 before the 2017 cycle shipped, and they haven’t reappeared since. A checklist or spec sheet citing either section predates NEC 2017 itself and should be updated to the current 690.13 disconnecting means language.
How do I find out which NEC cycle my AHJ enforces for disconnects and rapid shutdown?
Start with the state agency that adopts the electrical code, then check whether the local jurisdiction layers on amendments or a different effective date. Oregon’s Building Codes Division and the District of Columbia’s Department of Buildings both publish their adopted edition directly, and they’re not on the same cycle as each other. Confirm before assuming a 2023-only exception, like the carport exemption, applies to your project.
Get a disconnect and rapid shutdown design built for your AHJ’s cycle
A rapid shutdown citation that names the wrong edition, or a disconnect design that misses an exception your AHJ already allows, is exactly the kind of detail that turns a straightforward review into a resubmittal. Avila Solar Drafting builds every solar plan set to the NEC edition your AHJ has actually adopted, with the cycle named on the drawing so the reviewer can follow it. Standard turnaround is 2-3 business days, backed by 6 months of free revisions and Avila’s guarantee of accurate solar plan sets.
We work nationwide, with four exceptions: APS and SRP territory in Arizona, the City of Peoria, AZ, the City of Phoenix, AZ, and Los Angeles County (LABD), CA.
Prefer to talk it through first? Call 971-410-0655.
