Sistemas Solares Fotovoltaicos

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.