Energy Storage Permitting Guidebook - Report - Page 14
14
Energy Storage Guidebook
ESS are covered in Section R330 of Chapter 3 of the CRC, specifically residential ESS having a capacity of
3.6 MJ (1 kWh) or greater. This section outlines the following requirements for ESS:
ESS must be listed and labeled per UL 9540.
ESS must be installed per the manufacturer’s instructions.
Individual units must be separated from each other by no less than 3 feet.
Except if a smaller distance is permitted by the UL 9540 listing and manufacturer’s
installation instructions.
Note: In the 2025 CRC, this verbiage replaces the reference to the California Fire Code
(CFC) and “documented to be adequate based on large-scale fire testing.” This removes
the onus from the code official to validate the UL9540A testing and instead relies on the
manufacturer’s UL 9540 listing and the Nationally Recognized Testing Laboratory (NRTL)
that certified the product.
ESS shall only be installed in the following locations:
Detached garages and detached accessory structures.
Attached garages if separated from the dwelling unit in accordance with Table R302.6.
Outdoors no less than 3 feet away from doors and windows that enter the dwelling unit.
Except if smaller separation distances are permitted by the UL 9540 listing and
manufacturer’s installation instructions.
Enclosed utility closets, basements, and storage or utility spaces within dwelling units with
finished or noncombustible walls and ceilings.
Rooms and areas within dwelling units, basements, and attached garages in which ESS are installed
must include smoke alarms or heat alarms where appropriate.
Individual ESS units are limited to 20 kWh; larger individual unit sizes are permitted under the CFC and
must follow the requirements under the CFC.
This section of code also defines maximum allowable rating of ESS based on its installation location. There
are also requirements for ESS installed in locations subject to vehicle damage (such as a garage).
California Electrical Code
The California Electrical Code, Part 3 of Title 24, governs the installation of the electrical aspects of ESS for
all building and property types. Energy storage systems are covered in Section 706, specifically ESS with a
capacity greater than 1 kWh.
The California Electrical Code also calls out standards frequently referenced in ESS installations:
NFPA 855, Standard for the installation of ESS
NFPA 111, Standard on Stored Electrical Energy Emergency and Standby Systems
NECA 416, Recommended Practice for Installing ESS
UL 9540, Standard for Energy Storage Systems and Equipment
Additionally, for one- and two-family dwellings, an ESS shall include an emergency shutdown function to
stop the export of power from the ESS.
