Solar Photovoltaic Systems
Article 690 covers PV arrays, rapid shutdown, DC conductors and grounding for rooftop and ground-mount solar.
Why this code exists
Rooftop PV energizes conductors even with the utility off, endangering firefighters. Rapid-shutdown rules de-energize the array quickly.
The 2014 and 2017 editions introduced rapid-shutdown requirements limiting conductor voltage inside and near the array within seconds, so first responders can work safely.
When it applies
This is the heart of any PV job — rooftop residential, ground mounts, carports, the whole family. The second you have modules producing DC and feeding an inverter, Article 690 is driving your conductor sizing, grounding, labeling and rapid shutdown scheme.
Common mistakes
- Forgetting that module output climbs as temperature drops, so you undersize the string voltage and clip the inverter window on a cold morning.
- Skipping or mislocating the rapid shutdown initiation device that firefighters need to de-energize the array from the ground.
- Running exposed DC conductors without the right labeling and without a readily reachable disconnect.
In the field
On a recent 9 kW rooftop I always confirm the cold-weather Voc math before I ever pull a string. I would rather lose ten minutes with a calculator than find out in January that my array is over the inverter maximum and shutting down every clear cold morning.
The first thing I confirm on a rooftop array is rapid shutdown — because the day it matters, a firefighter is standing on that roof, not me.
See full history
- 1984 — Article 690 introduced.
- 2014 — Rapid shutdown required.
Related codes
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