The first level of distribution box should be set up in the area near the power supply, the power supply from the construction site power transformer low-voltage side of the cable line access, and install current transformer, active meter, reactive meter, ammeter, voltmeter, and the total switch, sub-switch. The switches in the main distribution box should be knife-fused switches (or leakage protection switches). The lead-in and lead-out wires should be threaded and have waterproof bends.
In the power supply system:
The primary distribution box: is the user's total power distribution box, control all the power supply centralized point.
Second-level distribution box: is the sub-distribution box, also called sub-box, generally responsible for a particular power supply area.
Tertiary distribution box: is the equipment distribution box also known as switch box, can only be used to control a device distribution box.
Expanded Information:
The first level distribution box, the second level distribution box, is also known as the switch box. p>The difference between the first level distribution box, the second level distribution box, the third level distribution box is:
The first level distribution box: construction power distribution cabinets for construction site construction power, is designed specifically for the project construction site situation is more special and designed in line with the construction department of the relevant construction power norms and standards. A level of cabinet using the lower into the lower line before the opening of the main busbar using copper rows connected to good contact within the measuring system with a safe and beautiful, rain-proof box top suitable for field work.
Second-level distribution box: for construction site construction power, is specially designed for the project construction site situation is more special and set up in line with the construction department of the relevant construction power norms and standards. The whole set of products can form a complete construction power three-level protection system, to achieve the purpose of a machine, a gate and a protection. The secondary box adopts internal and external door design, the appearance of plastic spraying safety and beautiful, rainproof box top suitable for field work.
Three-level power distribution: that is, in the total distribution box under the sub-distribution box, sub-distribution box under the switch box, switch box under the electricity equipment, forming a three-level power distribution. Two-level protection mainly refers to the use of leakage protection measures, in addition to the end of the switch box with leakage protector, but also in the last level of sub-distribution box or total distribution box with a level of leakage protector, the overall formation of two-level protection.
Baidu Encyclopedia - First-level distribution box