Image: Tesla patent
Tesla has filed a patent for the "Power disconnect system and method" to improve the safety of a home's power system. The systems described in the patent isolate the building circuit breaker panel from the mains circuit during an event that breaks the mains circuit.
In September 2021, Tesla filed a patent for the power disconnect system and method. The present invention relates generally to isolation point switches for building power connections, and more specifically, to incoming power meter isolation/backup switches for residential, single-family home power connections.
The patent was published March 17, 2022, and described systems and methods that isolate a building's circuit breaker panel from the mains circuit during a network outage event. The invention consists of a housing capable of interfacing with a power meter socket on the first side and a power meter on the second side, which contains power inputs from the network and power outputs to the circuit breaker panel, as well as an interruption circuit located inside and configured to interrupt the flow of electricity from the input supply to the power outlets.
Residential buildings are connected to the power grid through a power meter that measures consumption of electricity by all of the electronic devices associated with or powered inside of the building. Some residential buildings may have additional electricity sources, for example, a backup generator, battery, or solar power array. For safety reasons, these additional electricity sources must be disconnected from the power grid if the main power from the grid is interrupted. For example, if there is a power failure at the grid, the additional electricity sources should not be allowed to backfeed electricity to the grid. Doing so could injure workers repairing the power grid.
Various systems, such as Automatic Transfer Switches, exist that automatically disconnect the electrical feed from the power grid to a residential building when main power is interrupted. These systems may also enable use of the additional electricity sources to supplement or replace the electrical feed from the grid or provide backup power when the electrical feed from the grid fails. However, providing power to all of the circuits of a residential building during such a power failure can be problematic, explains Tesla.
As described above, introducing the isolation circuitry between the power meter and the building circuit breaker panel is difficult and costly to do. For example, in many buildings, power meters are installed or integrated with the circuit breaker panel, which may minimize or eliminate available locations between the building circuit breaker and power meter at which the isolation circuitry can be introduced. For example, on average, buildings that use a meter-load center combo panel, which may represent -70% of CA homes, 20+ loads or sub-circuits have to be relocated from the building circuit breaker panel to a new subpanel that includes separate backup loads. Relocating the loads or sub-circuits is a time-consuming and expensive process that adds to the direct installation cost that, thus, increases costs for introducing or retrofitting backup sources into an existing building.
One embodiment of the invention is a power disconnect system that provides isolation circuitry disposed between the input connections from the power grid and the power meter. By placing isolation circuitry between the power meter and a main power input for the building, the system can disconnect the main power from the entire circuit breaker panel.
© 2022, Eva Fox | Tesmanian. All rights reserved.
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About the Author
Eva Fox joined Tesmanian in 2019 to cover breaking news as an automotive journalist. The main topics that she covers are clean energy and electric vehicles. As a journalist, Eva is specialized in Tesla and topics related to the work and development of the company.