The Contractors State License Board of California on Aug. 6 approved a rule that would limit the number of contractors who are allowed to install energy storage systems, in the wake of new regulations starting in January 2020 that require nearly all new homes in the state to include rooftop solar.

The additional cost for each battery storage project from the new rule will be about $100, or about $1.5 million annually across the state, according to the California Department of Finance, and could lengthen construction schedules during California’s ongoing housing crisis, which Gov. Gavin Newsom has called the state’s “greatest challenge.”

Per the new rule, electrical contractors who hold a C-10 electrical license may continue to install battery storage systems, but solar systems installers, who only hold C-46 licenses, will now be limited to installing storage systems per the following requirements: a photovoltaic system of up to 10 kW on a single-family dwelling or duplex with a battery system that must not exceed 5 kW backup/20 kWh energy; the battery system is installed at the same time as the solar PV system; no upgrade or alteration is made to the existing electrical system.

California Building Officials Manager Katie Almond said C-46 contractors do not have the “proper training or experience to comply with current installation requirements. [Allowing] a C-46 licensee to perform this job function could jeopardize the integrity and safety of the energy storage unit and jeopardize the safety of those within the dwelling.”

However, the California Building Industry Association said it is “not aware of any building code or safety violations that have occurred during the installation of an energy storage system on a residential new home and the current industry practice is for the same contractor to install storage at the same time as the photovoltaic system.”

Furthermore, CBIA said if safety concerns exist, a C-46 contractor can follow plans drawn up by an electrical engineer to ensure proper installation practices. Approximately 70,000 single-family homes will be built in 2020 and will be required to have solar on the roof or to be tied to community solar, the CBIA added.

The California Energy Commission, which created the new home solar mandate, also opposed the new rule, stating, “New home construction and climate and decarbonization goals require affordability. Larger decarbonization goals may be compromised by the increased cost of mandating only certified electricians install energy storage systems.”

The CEC is concerned that the cost impact due to the new rule is more significant than estimated. “General contractors will not use a C-46 Solar contractor to install the photovoltaic system and a C-10 Electrical contractor to install the ESS; they will use the C-10 contractor for both if the C-46 cannot install the ESS.”

CSLB does not have data that demonstrates that C-46 contractors receive more complaints than C-10 contractors specific to energy storage system installation, according to the CEC.

California code defines a C-46 solar contactor as a contractor who installs, modifies, maintains, and repairs thermal and PV solar energy systems. A licensee classified in this section shall not undertake or perform building or construction trades, crafts, or skills, except when required to install a thermal or PV solar energy system.