Primary: The main distribution panel, supplies power from the transformer. 4kV to the distribution cabinet (primary distribution cabinet), then the outgoing line is led to the distribution box (secondary distribution box) in each building, and finally the outgoing line is led to the distribution cabinet. The terms primary, secondary, and tertiary distribution boxes are relative. Let's make an example for clarity: A newly constructed residential area introduces a 10kV power line to a substation. These boxes feature bottom entry and exit cables, front-opening doors, and main busbars connected with copper strips for optimal contact. 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. The complete set of products can form a complete three-level protection system for construction power, so as to achieve the purpose of one machine, one switch and one protection.
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