Low-voltage cable branch box

Abstract

The invention discloses a low-voltage cable branch box. The low-voltage cable branch box comprises at least one wire inlet unit, multiple wire outlet units and one connecting unit. The wire inlet unit comprises a three-phase live wire inlet element, a zero wire inlet element, a ground wire inlet element and a wire inlet frame, wherein each wire inlet element is separately arranged on the wire inlet frame to form an integral body. Each wire outlet unit comprises a three-phase live wire outlet element, a zero wire outlet element, a ground wire outlet element and a wire outlet frame, wherein each wire outlet element is separately arranged on the wire outlet frame to form an integral body. The elements in the wire inlet unit and the wire outlet units are respectively independently in electrical connection with the connecting unit. Compared to the prior art, the low-voltage cable branch box employs a three-phase five-wire design, can be connected with three-phase four wires or three-phase five wires and employs a three-phase live wire, zero wire and ground wire modular design. At the same time, a zero wire connecting piece is arranged in a space generated by stepped arrangement of three-phase live wires, the space is fully utilized, the land occupation area is reduced, a three-phase five-wire standard design is adopted, and the low-voltage cable branch box is suitable for large-scale production. Therefore, the application prospect is quite wide.

Description

technical field [0001] The invention relates to a device for a low-voltage power distribution system, in particular to a low-voltage cable branch box, which belongs to the technical field of cable branches. Background technique [0002] The low-voltage power distribution system refers to the power distribution system with a voltage less than 1kV. Composition of control and protection equipment. Among them, the 0.4kV power distribution system has been widely used in three-phase AC 380 / 220V, 55Hz power systems in urban residential quarters, industrial and mining enterprises, construction sites, etc. It is especially suitable for various public facilities such as urban streets, colleges, and residential areas. It is used for receiving or distributing electric energy in the three-phase or single-phase power transmission and distribution or single-phase lighting system. [0003] In the low-voltage distribution network, the transmission line generally adopts a three-phase four-w...

AI Technical Summary

Problems solved by technology

(2) The connection terminals of the protective neutral wire or the protective ground wire are not connected properly, causing a fire

(4) If the wire diameter of the protective neutral wire or the protective ground wire is too small, when a large leakage current passes through, the temperature of the line will rise faster, which can also cause a fire

[0009] Chinese patent application CN201310425891 discloses a branch box for cables, which improves the structure of the box body of the branch box, and uses the combination of the cover plate on the cutting edge and the branch box composed of a whole piece of aluminum plate to replace the previous rectangular parallelepiped branch box, saving trimming Saved materials, reducing joints and welding, but the problem of circuit structure arrangement in the cable branch box can not be solved; Chinese patent application CN201210321923 discloses a cable branch box, which includes a cable room, a busbar room, and an explosion-proof and anti-theft box Body, rain cover, charged indicator, fault indicator and microcomputer controller, simple in structure, high in safety and reliability, and easy to find faults quickly, but the above-mentioned settings cannot solve the problem of the circuit structure itself; a disclosed Chinese patent application CN201310451536 A fully sealed low-voltage cable branch box, the box body is sealed, the busbar is made of insulating materials around the outside, the busbar frame is equipped with a socket connected to the cable, and double-sealed protection is used to prevent the line from short circuit when it is exposed to water. Insulating materials are used around the busbar in the cable branch box, which affects the conductivity and is inconvenient to maintain; the low-voltage cable branch box disclosed in Chinese patent CN201320069330 includes a bottom plate, and the bottom plate is provided with a three-phase busbar and an insulating cover for closing the busbar. An insulating cover is provided with a socket hole, and when installing the output module, no more installation tools are required, which is simple and convenient, but the safety problem of the neutral line in the low-voltage cable branch box cannot be solved; the low-voltage cable branch box disclosed in Chinese patent CN201220586472 Outlet arrangement structure, three-phase line and neutral line outlet confluence presents a horizontal layered structure as a whole, and there will be no phenomenon of cable crossing and overlapping, but the three-phase line and neutral line are connected to the branch box through bolts, the connection method is complicated, and it is not convenient to quickly Installation and maintenance; Chinese patent CN200920180719 utility model discloses a low-voltage cable branch box. The three-phase incoming and outgoing lines of the low-voltage cable branch box are equipped with fuse-type circuit breaker switches to protect the incoming and outgoing lines. , low-voltage switchgear, etc., which provides great convenience for cable networking, but in this kind of low-voltage cable branch box, once an outgoing line unit fails, it will cause the entire incoming line unit to fail, so all outgoing line units will be broken. Electricity, power outage area is wide, maintenance difficulty increases

[0010] In summary, among the various improvements made to the low-voltage cable branch box, the current low-voltage cable branch box products do not involve the improvement of the circuit in the cable branch box, and have not solved the core problem of this type of product: the current low-voltage cable branch box products generally They are all three-phase four-wire systems, without ground wire settings, and the three-phase wires and neutral wires are not integrated together, but are set separately. The three-phase wires are set in the busbar system in the low-voltage cable branch box, and the neutral wire N (Neutral line) Depending on the box setting, the entire low-voltage cable branch box needs a busbar system to cooperate with the box. The neutral line is exposed outside. When the three-phase voltage is unbalanced or the neutral point potential changes, the neutral line may be charged, especially The neutral wire still uses copper bars and manual wiring. Once a person accidentally touches the exposed neutral wire on the box, there will be a risk of electric shock

Moreover, in the opening or closing process of the current low-voltage cable branch box, it is impossible to ensure that the ground wire, neutral wire and then the three-phase live wire are connected through the structure of the equipment itself; on the contrary, when the circuit is broken, the three-phase live wire, The zero line and then the ground line need to rely on professional knowledge to judge the charging situation, and cannot provide maximum protection for people and equipment; in addition, each outgoing line unit is not independent, and when one outgoing line unit fails, it will affect the normal work of other outgoing line units and cause power outages. The area increases, increasing the difficulty of maintenance and inspection

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