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Chapter 3 — BUILDING PLANNING

Section R330 — ENERGY STORAGE SYSTEMS

2025 California Residential Code (Title 24, Part 2.5) · 2025 edition · updated 2026-07-29 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

R330.1 General.

Energy storage systems (ESS) shall comply with the provisions of this section.

Exceptions:

  1. ESS listed and labeled for use in habitable spaces, in accordance with UL 9540 and where installed in accordance with the listing, the manufacturer’s instructions and the California Electrical Code.
  2. ESS less than 1 kWh (3.6 megajoules).

R330.2 Equipment listings.

Energy storage systems (ESS) shall be listed and labeled in accordance with UL 9540.

Exception: Where approved, repurposed unlisted battery systems from electric vehicles are allowed to be installed outdoors or in detached sheds located not less than 5 feet (1524 mm) from exterior walls, property lines and public ways.

R330.3 Installation.

ESS shall be installed in accordance with the manufacturer’s instructions and their listing.

R330.3.1 Spacing. Individual units shall be separated from each other by not less than 3 feet (914 mm) except where other separation distances are specified by the ESS listing and the manufacturer’s installation instructions.

R330.4 Locations. ESS shall be installed only in the following locations:

  1. Detached garages and detached accessory structures.

  2. Attached garages separated from the dwelling unit living space in accordance with Section R302.6.

  3. Outdoors or on the exterior side of exterior walls located not less than 3 feet (914 mm) from doors and windows directly entering the dwelling unit, except where smaller separation distances are permitted by the UL 9540 listing and manufacturer’s installation instructions.

  4. Enclosed utility closets, basements, storage or utility spaces within dwelling units with finished or noncombustible walls and ceilings. Walls and ceilings of unfinished wood-framed construction shall be provided with not less than [5] / 8 -inch (15.9 mm) Type X gypsum wallboard. Openings into the dwelling shall be equipped with solid wood doors not less than 1 [3] / 8 inches (35 mm) in thickness, solid or honeycomb-core steel doors not less than 1 [3] / 8 inches (35 mm) in thickness, or doors with a 20-minute fire protection rating. Doors shall be self-latching and equipped with a self-closing or an automatic-closing device. Penetrations through the required gypsum wallboard into the dwelling shall be protected as required by Section R302.11, Item 4.

� ESS shall not be installed in sleeping rooms, or closets or spaces opening directly into sleeping rooms.

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R330.5 Energy ratings.

Individual ESS units shall have a maximum rating of 20 kWh. The ratings of the ESS in each location shall not exceed the ratings in Table R330.5. The total aggregate ratings of ESS on the property shall not exceed 600 kWh.

ESS installations exceeding the permitted individual or aggregate ratings shall be installed in accordance with Section 1207 of the California Fire Code.

TABLE R330.5—MAXIMUM AGGREGATE RATINGS OF ESS

LOCATION MAXIMUM
AGGREGATE
RATINGS (kWh)		 INSTALLATION REQUIREMENTS
Within utility closets, basements, and storage or utility
spaces located within dwellings		 40
In attached garages 80
On or within 3 feet of exterior walls of dwellings and
attached garages		 100
On or within 3 feet of exterior walls of dwellings and
attached garages		 200 Exterior walls and eaves are constructed with noncombustible
surfacesa
In detached garages and detached accessory structures 200
In detached garages and detached accessory structures 600 Detached garage or detached accessory structure is a minimum
10 feet away from property lines and dwellings
Outdoors on the ground 200 ESS is a minimum 3 feet away from property lines and dwellings
Outdoors on the ground 600 ESS is a minimum 10 feet away from property lines and dwellings
For SI: 1 foot = 304.8 mm.
a. Noncombustible wall surface shall extend in accordance with all the following:
1. A minimum of 5 feet horizontally from the edge of the ESS.
2. A minimum of 1 foot vertically below the bottom edge of the ESS.
3. A minimum of 8 feet vertically above the ESS, or to a non-combustible eave, whichever is less.
The code official is authorized to approve reductions of installation requirements based on large-scale fire testing complying with Section 1207.1.5 of the California Fire Code.

R330.6 Electrical installation.

ESS shall be installed in accordance with the California Electrical Code. Inverters shall be listed and labeled in accordance with UL 1741 or provided as part of the UL 9540 listing. Systems connected to the utility grid shall use inverters listed for utility interaction.

R330.7 Fire detection.

Rooms and areas within dwelling units, basements and attached garages in which ESS are installed shall be protected by smoke alarms in accordance with Section R310. A heat detector, listed and interconnected to the smoke alarms, shall be installed in locations within dwelling units and attached garages where smoke alarms cannot be installed based on their listing.

[SFM] ESS installed in Group R-3 and townhomes shall comply with the following: 1. Rooms and areas within dwellings units, sleeping units, basements and attached garages in which ESS are installed shall be protected by smoke alarms in accordance with Section R314. 2. A listed heat alarm interconnected to the smoke alarms shall be installed in locations within dwelling units, sleeping units and attached garages where smoke alarms cannot be installed based on their listing.

R330.8 Protection from impact.

ESS installed in a location subject to vehicle damage in accordance with Section R330.8.1 or R330.8.2 shall be provided with impact protection in accordance with Section R328.8.3.

R330.8.1 Garages. Where an ESS is installed in the normal driving path of vehicle travel within a garage, impact protection complying with Section R330.8.3 shall be provided. The normal driving path is a space between the garage vehicle opening and the interior face of the back wall to a height of 48 inches (1219 mm) above the finished floor. The width of the normal driving path shall be equal to the width of the garage door opening. Impact protection shall also be provided for an ESS installed at either of the following locations (see Figure R330.8.1):

  1. On the interior face of the back wall and located within 36 inches (914 mm) to the left or to the right of the normal driving path.
  2. On the interior face of a side wall and located within 24 inches (610 mm) from the back wall and 36 inches (914 mm) of the normal driving path.

Exception: Where the clear height of the vehicle garage opening is 7 feet 6 inches (2286 mm) or less, ESS installed not less than 36 inches (914 mm) above finished floor are not subject to vehicle impact protection requirements.

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BUILDING PLANNING

FIGURE R330.8.1—ESS VEHICLE IMPACT PROTECTION

For SI: 1 inch = 25.4 mm.

R330.8.2 Other locations subject to vehicle impact. Where an ESS is installed in a location other than as defined in Section R330.8.1 and is subject to vehicle damage, impact protection shall be provided in accordance with Section R330.8.3.

R330.8.3 Impact protection options. ESS protection shall comply with one of the following:

  1. Bollards constructed in accordance with one of the following: 1.1. Minimum 48 inches (1219 mm) in length by 3 inches (76 mm) in diameter Schedule 80 steel pipe embedded in a concrete pier not less than 12 inches (305 mm) deep and 6 inches (152 mm) in diameter, with not less than 36 inches (914 mm) of pipe exposed, filled with concrete and spaced at a maximum interval of 5 feet (1524 mm). Each bollard shall be located not less than 6 inches (152 mm) from an ESS. 1.2. Minimum 36 inches (914 mm) in height by 3 inches (76 mm) in diameter Schedule 80 steel pipe fully welded to a steel plate not less than 8 inches (203 mm) in length by [1] / 4 inch (6.4 mm) in thickness and bolted to a concrete floor by means of 4 [1] / 2 -inch (114 mm) concrete anchors imbedded not less than 3 inches (76 mm). Spacing shall be not greater than 60 inches (1524 mm), and each bollard shall be located not less than 6 inches (152 mm) from the ESS.

ameter Schedule 80 steel pipe fully welded to a steel plate not less than 8 inches (203 mm) in length by [1] / 4 inch (6.4 mm) in thickness and bolted to a concrete floor by means of 4 [1] / 2 -inch (114 mm) concrete anchors imbedded not less than 3 inches (76 mm). Spacing shall be not greater than 60 inches (1524 mm), and each bollard shall be located not less than 6 inches (152 mm) from the ESS.

1.3. Premanufactured steel pipe bollards filled with concrete and anchored in accordance with the manufacturer’s installation instructions, with spacing not greater than 60 inches (1524 mm). Each bollard shall be located not less than 6 inches (152 mm) from the ESS. 2. Wheel barriers constructed in accordance with one of the following: 2.1. Concrete or polymer 4 inches (102 mm) in height by 5 inches (127 mm) in width by 70 inches (1778 mm) in length, anchored to the concrete floor not less than every 36 inches (914 mm) and located not less than 54 inches (1372 mm) from the ESS. Concrete anchors not less than 3 [1] / 2 inches (89 mm) in diameter with 3-inch

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(76 mm) embedment per barrier shall be used. Spacing between barriers shall be not greater than 36 inches (914 mm).

2.2. Premanufactured wheel barriers shall be anchored in accordance with the manufacturer’s installation

instructions.

  1. An approved method designed to resist an impact of 2,000 pounds per square foot (95 760 N/m [2] ) in the direction of travel at 24 inches (610 mm) above grade.

R330.9 Ventilation.

Indoor installations of ESS that produce hydrogen or other flammable gases during charging shall be provided with mechanical ventilation in accordance with the California Mechanical Code.

R330.10 Electric vehicle use.

The temporary use of an owner or occupant’s electric-powered vehicle to power a dwelling unit while parked in an attached or detached garage or outdoors shall comply with the vehicle manufacturer’s instructions and the California Electrical Code.

R330.11 Documentation and labeling. The following information shall be provided:

  1. A copy of the manufacturer’s installation, operation, maintenance and decommissioning instructions shall be provided to the owner or placed in a conspicuous location near the ESS equipment.
  2. A label on the installed system containing the contact information for the qualified maintenance and service providers.

R330.12 Toxic and highly toxic gas.

ESS that have the potential to release toxic or highly toxic gas during charging, discharging and normal use conditions shall not be installed within Group R-3 or R-4 occupancies.

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▸ Contents — 2025 California Residential Code (Title 24, Part 2.5)
2025 California Residential Code (Title 24, Part 2.5)
  1. Chapter 1 — ADMINISTRATION
  2. Chapter 2 — DEFINITIONS
  3. ▸ Chapter 3 — BUILDING PLANNING
    Overview
    1. Section R300 — SITE DRAINAGE
    2. Section R301 — DESIGN CRITERIA
    3. Section R302 — FIRE-RESISTANT CONSTRUCTION
    4. Section R303 — FOAM PLASTIC
    5. Section R304 — PROTECTION OF WOOD AND WOOD-BASED PRODUCTS AGAI…
    6. Section R305 — PROTECTION AGAINST SUBTERRANEAN TERMITES
    7. Section R306 — FLOOD-RESISTANT CONSTRUCTION
    8. Section R307 — STORM SHELTERS
    9. Section R308 — SITE ADDRESS
    10. Section R309 — AUTOMATIC SPRINKLER SYSTEMS
    11. Section R310 — SMOKE ALARMS
    12. Section R311 — CARBON MONOXIDE ALARMS
    13. Section R312 — MINIMUM ROOM AREAS
    14. Section R313 — CEILING HEIGHT
    15. Section R314 — MEZZANINES
    16. Section R315 — SLEEPING LOFTS
    17. Section R316 — HABITABLE ATTICS
    18. Section R317 — GARAGES AND CARPORTS
    19. Section R318 — MEANS OF EGRESS
    20. Section R319 — EMERGENCY ESCAPE AND RESCUE OPENINGS
    21. Section R320 — HANDRAILS
    22. Section R321 — GUARDS AND WINDOW FALL PROTECTION
    23. Section R322 — ACCESSIBILITY
    24. Section R323 — ELEVATORS AND PLATFORM LIFTS
    25. Section R324 — GLAZING
    26. Section R325 — LIGHT, VENTILATION AND HEATING
    27. Section R326 — SANITATION
    28. Section R327 — TOILET, BATH AND SHOWER SPACES
    29. Section R328 — AGING-IN-PLACE DESIGN AND FALL PREVENTION
    30. Section R329 — SOLAR ENERGY SYSTEMS
    31. Section R330 — ENERGY STORAGE SYSTEMS
    32. Section R331 — STATIONARY ENGINE GENERATORS
    33. Section R332 — STATIONARY FUEL CELL POWER SYSTEMS
    34. Section R333 — RESERVED
    35. Section R334 — CONSTRUCTION WASTE REDUCTION, DISPOSAL AND RECY…
    36. Section R335 — SPECIAL PROVISIONS FOR LICENSED 24-HOUR CARE FA…
    37. Section R336 — LARGE FAMILY DAY-CARE HOMES
    38. Section R337 — MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR…
    39. Section R338 — ELECTRIC VEHICLE
    40. Section 339 — RESERVED
    41. Section R340 — POLLUTANT CONTROL
  4. Chapter 4 — FOUNDATIONS
  5. Chapter 5 — FLOORS
  6. Chapter 6 — WALL CONSTRUCTION
  7. Chapter 7 — WALL COVERING
  8. Chapter 8 — ROOF-CEILING CONSTRUCTION
  9. Chapter 9 — ROOF ASSEMBLIES
  10. Chapter 10 — CHIMNEYS AND FIREPLACES
  11. Chapter 44 — REFERENCED STANDARDS
  12. Appendix AA — BOARD OF APPEALS
  13. Appendix AB — PERMIT FEES
  14. Appendix AC — RESERVED
  15. Appendix BA — RESERVED
  16. Appendix BB — TINY HOUSES
  17. Appendix BC — RESERVED
  18. Appendix BD — RESERVED
  19. Appendix BE — RADON CONTROL METHODS
  20. Appendix BF — PATIO COVERS
  21. Appendix BG — SOUND TRANSMISSION
  22. Appendix BH — AUTOMATIC VEHICULAR GATES
  23. Appendix BI — LIGHT STRAW-CLAY CONSTRUCTION
  24. Appendix BJ — STRAWBALE CONSTRUCTION
  25. Appendix BK — COB CONSTRUCTION (MONOLITHIC ADOBE)
  26. Appendix BL — HEMP-LIME (HEMPCRETE) CONSTRUCTION
  27. Appendix BM — 3D-PRINTED BUILDING CONSTRUCTION
  28. Appendix BN — EXTENDED PLATE WALL CONSTRUCTION
  29. Appendix BO — EXISTING BUILDINGS AND STRUCTURES
  30. Appendix CA — RESERVED
  31. Appendix CB — RESERVED
  32. Appendix CC — RESERVED
  33. Appendix CD — RESERVED
  34. Appendix CE — RESERVED
  35. Appendix CF — RESERVED
  36. Appendix CG — NONSEWERED SANITATION SYSTEMS
  37. Appendix CH — PRIVATE SEWAGE DISPOSAL
  38. Appendix CI — SWIMMING POOL SAFETY ACT
  39. Appendix CJ — EMERGENCY HOUSING
  40. Appendix CK — AREAS PROTECTED BY THE FACILITIES OF THE CENTRAL…

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