Three-Tier Power Distribution System in a Newly Constructed Residential Area
In a newly constructed residential area, a 10kV power line is introduced into the substation. After stepping down the voltage through the transformer's low-voltage side (0.4kV), power distribution is achieved through three levels of distribution boxes: the main distribution board, secondary distribution boards, and tertiary distribution boards.
Main Distribution Board
Serves as the primary distribution point for the entire project, directly connected to the transformer providing 0.4kV power.
Does not supply power directly to end-use equipment but acts as a centralized power distribution hub.
Includes components such as isolating switches, circuit breakers, and Residual Current Devices (RCDs) to ensure overall circuit safety.
Secondary Distribution Boards
Designed for specific buildings or floors, responsible for distributing three-phase power.
Connects to motors or other heavy loads, utilizing larger capacity three-phase circuit breakers to ensure safe operation.
Emphasizes protective measures like dual-door protection, durable coatings, and rainproof designs suitable for outdoor environments, ensuring electrical safety during the intermediate stages.
Tertiary Distribution Boards
Ultimately connects to home systems or specific pieces of equipment, supplying 220V single-phase power.
Implements strict safety standards, such as "one device, one circuit breaker, one RCD, one box," ensuring independent circuit protection for each device.
May include fixed or portable boxes to ensure electrical safety and adhere to a "two-layer protection" strategy, meaning RCDs at both the tertiary (device level) and secondary (area level).
This three-tier distribution system structure — with the main distribution board acting as the primary delivery point, secondary distribution boards serving as intermediate power hubs, and tertiary distribution boards directly supplying end-use equipment — ensures effective power management, high safety, and reliability in complex electrical systems, especially suited for the power needs of construction sites or large projects.
