2025 CalGreen: Pre-Wiring for Future Electrification Requirements

The City of Menlo Park has adopted a local amendment that adds §4.106.5 to the 2025 California Green Building Standards Code (CALGreen) (Muni Code §12.18.070). The added section establishes two separate requirements for pre-wiring and reservation of breaker space for future electrification of existing single-family homes. Specifically: 

• §4.106.5.1 (Muni Code §12.18.080) applies to proposed project scope that includes the addition or alteration to a space that contains a gas fired appliance; and 
• §4.106.5.2 (Muni Code §12.18.090) applies to proposed project scope that includes the replacement/upgrade to the main electric panel.

Please refer to Muni Code §12.18.080 and §12.18.090 for specific requirements.

§4.106.5.1 Addition of electrical raceway within three feet (3’) of a gas appliance and reservation of breaker space

The requirements of §4.106.5.1 apply to all additions, alterations, repairs, and/or accessory dwelling unit conversions projects undertaken voluntarily by property owners that are adding or altering a space that contains a gas fired appliance Which required: 

• Reservation of breaker space and electrical capacity in the electrical panel serving the space (main panel or sub-panel) for future installation of an electric appliance(s); and 
• Installation of an electrical raceway(s) (conduit) or conductors from the electric panel to a junction box or outlet within three feet of the gas-fired appliance that is located in the area of alteration.

Example: 
If the proposed project is to remodel a kitchen that has a gas stove, then the project plans must show the inclusion of the reservation of breaker spaces in the electrical panel serving the space and an electrical conduit or conductors to be installed from the electric panel to a junction box or outlet within three feet of the gas-fired appliance. Field verification of these elements will be confirmed by the City Building Inspector during construction.

Exception:
There is an exception to the new pre-wiring requirements that apply when the existing electrical panel does not have the electrical capacity to facilitate the replacement of the gas-fired equipment to electric equipment in the future. In this situation, the exception allows the breaker space and electrical capacity to be for as much of the requirement as practicable. In all cases, the raceways or conduit are still required to be installed.

§4.106.5.2 Replacement/upgrade to the main electric panel

The requirements of §4.106.5.2 apply to all additions, alterations, repairs, and/or accessory dwelling unit conversions projects include the replacement/upgrade to the main electric panel.

The City of Menlo Park has adopted a local amendment adding § 4.106.5.2 Prewiring requirements to the 2025 California Green Building Standards Code (CalGreen) (Muni Code § 12.18.090) which establishes future electrification requirements when a Building permit application includes the replacement/upgrade to the main electric panel.

The requirements apply to all additions, alterations and repair construction projects that include the replacement or upgrade to the main electric panel for:

• Residential buildings (both single-family and multi-family buildings); and 
• Accessory dwelling unit conversions project 

The requirements established in §4.106.5.2  do not impose requirements to use specific appliances, nor do they prohibit the use of gas as an energy source or gas appliances. Additionally, the requirements do not require the installation of any heat pump-based space or water heating equipment, electric vehicle charges or electric stove. 

Single-family residential buildings and accessory dwelling unit conversions

The requirements of Section 4.106.5.2 are as follows:

1. The new main electrical panel must have electrical capacity for and reservation of breaker space in the panel to accommodate the existing single family electrical load and the future electrification of:
   i. An electric stove and oven if the current stove and/or oven are gas;
   ii. An electric clothes dryer if the current clothes dryer is gas;
   iii. One Level 2 Electric Vehicle (EV) charger;
   iv. Photovoltaic system (PV) size based on §150.1(c)14 of the 2022 California Energy Code; and
2. All reserved breaker spaces shall be permanently marked as “For Future EV charging, PV and heat pump water heater use.”
3. Electrical capacity for and reservation of breaker space in the panel to accommodate a dedicated 240-volt branch circuit for a heat pump water heater. Electrical conductors for the branch circuit shall be installed within three (3) feet from the existing water heater location and shall be rated at 30 amps minimum. Both ends of the unused conductor shall be labeled with the word “spare” and be identified as 240-volt ready.

Exception:
There is an exception to requirement number 3 which allows Single-family and multi-family homes to designate a space at least 2.5 feet by 2.5 feet wide and 7 feet tall with access to hot and cold water suitable for the future installation of a heat pump water heater (HPWH) in an alternate location at discretion of building official.

The exception is intended to address the possibility that an applicant may want a heat pump water heater to be installed in the future in a different location than the existing gas-fired hot water heater which is why the code language allows for the applicant to identify another suitable location for the water heater when pre-wiring.

Multi-family residential buildings

The requirements of Section 4.106.5.2 are as follows:

1. Electrical capacity for and reservation of breaker space in the panel to accommodate a dedicated 240-volt branch circuit for a heat pump water heater. 
2. Electrical conductors for the branch circuit shall be installed within three (3) feet from the existing water heater location and shall be rated at 30 amps minimum. 
3. Both ends of the unused conductor shall be labeled with the word “spare” and be identified as 240-volt ready.

Exception:
There is an exception to the requirement which allows residential buildings other than R-3 occupancies as defined in the California Building Code, to not reserve the electrical capacity and breaker space in the panel and not install electrical conductors when the water heaters are located in each dwelling unit.

Please refer to Muni Code §12.13.010 and §12.13.020 for the specifics of the requirements.