NEC 2023 · Section 690.12
NEC 690.12 — Rapid Shutdown of PV Systems on Buildings
Rapid shutdown exists for the firefighter on the roof: one initiation action must bring PV conductors on or in a building down to safe voltages within 30 seconds. Here are the limits, the boundary, and the hardware that satisfies them.
690.12(B) — Controlled Conductor Limits
The “array boundary” is 1 ft from the array in all directions.
| Zone | Voltage Limit | Time |
|---|---|---|
| Outside the array boundary (more than 1 ft from the array) | 30V or less | Within 30 seconds of initiation |
| Inside the array boundary (within 1 ft of the array) | 80V or less | Within 30 seconds of initiation |
Inside the boundary, an alternative to the 80V limit is a PV hazard control system (PVHCS) listed or field-labeled for the purpose, installed per its instructions.
Initiation & Labeling
- • Initiation device — 690.12(C): one readily accessible initiation device (or the service disconnecting means) starts the shutdown for the whole system. Off position = shutdown initiated. Multiple PV systems need either a single device or grouped devices with no more than six handle motions.
- • Labeling — 690.56(C): buildings with rapid shutdown need the standardized reflective placard at the service equipment identifying the type of rapid shutdown (whole-array vs. outside-boundary-only) and the initiation device location.
- • Equipment: rapid-shutdown functions must be provided by equipment listed for the purpose — module-level power electronics (microinverters, optimizers with RSD), string-level rapid-shutdown boxes, or listed hazard-control systems.
What's In and What's Out
- • Applies: PV system circuits on or in buildings — the standard residential and commercial rooftop install.
- • Exempt: ground-mounted arrays; carports and similar non-enclosed structures are treated differently by many AHJs — confirm locally.
- • Retrofits: the code edition in force at permit time governs — expanding an older array usually pulls the new work (and sometimes the whole system) under current rapid-shutdown rules.
- • Rapid shutdown is not a substitute for the PV system disconnecting means (690.13) or equipment disconnects (690.15).
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