Electrical
Rapid shutdown labeling: getting NEC 690.12 placards right first time
Short answer
NEC 690.12 sets the rapid shutdown requirement; the placards that announce it are specified in 690.56(C). A building with a rapid shutdown system needs a permanent label at the service disconnecting means carrying the prescribed wording and the diagram showing what the system shuts down, plus a separate label at the initiation device. Field-applied labels must also meet the durability requirements of 110.21(B).
Written against NEC 2020 and NEC 2023. The requirement exists in NEC 2017 with different detail. Confirm the adopted edition, and check the exact wording and diagram in the code text itself before ordering placards.
Two different sections
People conflate them. 690.12 is the functional requirement — conductors leaving the array must be reduced to a safe level within a set time when shutdown is initiated. 690.56(C) is the labelling that tells a firefighter the building has such a system and what it does.
Your equipment selection satisfies 690.12. Your label schedule satisfies 690.56(C). A set can be fully compliant on the first and fail on the second.
What has to be posted
- At the service disconnecting means — a permanent label stating the building is equipped with rapid shutdown, together with the diagram prescribed by the code showing whether the system shuts down the array and the conductors leaving it, or the conductors only.
- At the initiation device — a label identifying it as the rapid shutdown switch for the PV system.
- Where multiple systems share a building — labelling that makes clear which system each device belongs to.
The diagram matters as much as the words. The code reproduces the figure it expects; a label with the right sentence and the wrong diagram is still wrong.
Durability, which is where inspections fail
Field-applied hazard markings fall under 110.21(B). They have to be suitable for the environment — which outdoors, on a wall, in sun, means UV-stable and properly adhered. Not a printed sheet in a plastic sleeve, and not a label that has already lifted at the corners when the inspector arrives.
This is the single most common reason a solar job passes plan check and then fails the first inspection. Nothing about the design was wrong; the placards were an afterthought.
How to kill the problem at the drawing stage
Put a label schedule on its own sheet. For each placard: exact wording, the diagram where one is required, the mounting location, and the material. An installer who can order and place straight off the sheet does not improvise, and an inspector reading the same sheet has nothing to interpret.
| Placard | Goes where |
|---|---|
| Rapid shutdown notice and diagram | Service disconnecting means |
| Rapid shutdown switch identification | At the initiation device |
| PV system disconnect | At the PV disconnect |
| Dual power source warning | Main service panel |
| Interconnection and ratings | Point of interconnection |
Treat the table above as the shape of a schedule, not as the schedule itself — the required set depends on the system and the adopted edition.