What are Balance of Systems Components?

Balance of Systems (BOS) components for solar energy systems encompass the various auxiliary components necessary for the efficient operation of a solar PV system. BOS components include safety equipment such as disconnect switches and critical load panels. These components are crucial for ensuring system reliability and maintaining safety standards in solar energy installations.

Rapid Shutdown Device

The rapid shutdown device (RSD) is a safety mechanism required in photovoltaic (PV) systems to swiftly deactivate or isolate the system during emergencies or maintenance to mitigate electrical hazards. This device ensures that responders can quickly de-energize the PV system in an emergency, such as a fire, to prevent electrical shock or fire spread. As per the National Electrical Code (NEC), Section 690.12, rapid shutdown devices are mandated for PV systems on buildings. In Washington, we install an RSD with every solar energy system, whether a knife-style disconnect or the inverter functioning as the RSD.

Battery Critical Load Panels

A critical load panel for batteries is a dedicated electrical panel designed to prioritize and power essential appliances and circuits during power outages. The critical load panel ensures continuous electricity supply to vital loads, such as medical equipment, security systems, refrigeration, and lighting, even when the primary power source fails. By isolating critical loads from non-essential ones, this panel maximizes the efficiency and longevity of the battery backup system, providing resilience and reliability during emergencies or grid disruptions.