Which safety device is required in all PV systems according to Article 690?

In photovoltaic (PV) systems, Article 690 of the National Electrical Code (NEC) mandates the inclusion of a disconnecting means or switch as a critical safety device. This requirement is essential for ensuring both the safety of maintenance personnel and the overall safety of the installation.

The disconnecting means enables the system to be safely isolated from the electrical supply, which is particularly important during maintenance or emergencies. It allows workers to cut off power to the solar array and associated equipment to prevent electric shock or other hazards. This switch must be easily accessible to allow quick operation when necessary.

By requiring a disconnecting means, the NEC prioritizes safety in the design and installation of PV systems. It establishes a standardized way to ensure that any work performed on the system can be done without risk of electrocution. Other safety devices, while important, do not fulfill this specific role, making the disconnecting means a unique and necessary requirement within Article 690.