Quick Answer
NEC 690.12 requires solar panel systems to have a rapid shutdown feature that disconnects power to the DC side of the system within 30 seconds when the AC side is de-energized. This reduces shock hazards and allows for faster maintenance. The cost impact is primarily seen in the initial installation.
Understanding NEC 690.12 Requirements
The NEC 690.12 rapid shutdown requirement is a critical aspect of solar panel system design and installation. This feature ensures that DC power is isolated from the AC side of the system when the AC side is de-energized, which is typically during maintenance, repair, or installation. The standard allows for different methods to achieve rapid shutdown, including using a dedicated rapid shutdown controller or integrating the function into existing DC-DC converters or inverters.
Compliance Costs and Options
Complying with NEC 690.12 can add $0.50 to $2.50 per watt to the upfront cost of a solar panel system, depending on the specific implementation and the type of rapid shutdown devices used. For a typical residential system with 5 kW of power, this translates to an additional $2,500 to $12,500 in upfront costs. System designers and installers can choose from various rapid shutdown devices, including dedicated controllers and integrated inverters, which can affect overall system costs.
Selecting a Rapid Shutdown Solution
When selecting a rapid shutdown solution, system designers should consider factors such as cost, reliability, and ease of installation. Some popular options include the Rapid Shutdown System (RSS) by Schneider Electric, the Enel X Rapid Shutdown Controller, and the ABB PVS800 Inverter, which integrates rapid shutdown functionality. The choice of rapid shutdown device will depend on the specific needs of the project and the preferences of the system designer and installer.
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