Distribution Box Installation Specification
I. operating principle of distribution box
Distribution box is the switch equipment, measuring instruments, protective appliances and auxiliary equipment assembled in closed or semi-closed metal cabinet or screen width according to the electrical wiring requirements, forming a low-voltage distribution device. During normal operation, the circuit can be switched on or off manually or automatically. In case of failure or abnormal operation, cut off the circuit or give an alarm with the help of protective appliance. By means of measuring instrument, various parameters in operation can be displayed, and some electrical parameters can be adjusted to indicate or send signals for deviation from normal working state. Often used in the distribution, distribution, substation.
Ii. Structure and use of distribution box
(1) structure
Power distribution box, power distribution cabinet, power distribution panel, power distribution panel, etc., is a complete set of equipment for centralized installation of switch integrated power distribution box wiring guidance integrated power distribution box wiring guidance, instrument and other equipment.
(2) purpose
Purpose of distribution box: reasonable distribution of electric energy, convenient to open and close the operation of the circuit. It has a high level of safety protection, and can display the on-off state of the circuit directly. Easy to manage, when the occurrence of circuit fault is conducive to maintenance. Ac contactor for elevator distribution box
(3) categories
Commonly used power distribution box has wooden and metallic make two kinds, because metal power distribution box protects grade to want a few taller, still use metal so more.
Classification by structural characteristics and USES:
(1) fixed face plate type switch cabinet, often referred to as switch board or distribution screen. It is a kind of open type switch cabinet that has face plate to block, the front has protective effect, the back and side still can touch live part, protective grade is low, can be used only to the industry and mining enterprise with low requirement to supply continuity and reliability, make substation room centralized power supply to use.
(2) protective (i.e. enclosed) switchgear refers to a low-voltage switchgear in which all sides are closed except the mounting surface. The switch, protection and monitoring control electrical components of the cabinet are installed in a closed case made of steel or insulating material, reliable wall or off wall installation. Between each loop inside the cabinet can not add isolation measure, also can use the metal plate that ground or insulation board undertakes isolation. Usually the door is mechanically interlocked with the main switch. In addition, there is a protective type of table type switch cabinet (that is, the console), the panel is equipped with control, measurement, signal and other electrical appliances. Protective switchgear is mainly used as the distribution device in the process site.
(3) drawer type switch cabinet. This kind of switch cabinet is made of steel plate into a closed shell, the electrical components of the incoming and outgoing circuit are installed in the drawer that can be drawn out, forming a functional unit that can complete a certain kind of power supply task. Between the function unit and the bus or cable, the function board made of earthing metal or plastic is separated to form the bus, the function unit and the cable. There is also isolation between each functional unit. Drawer type switch cabinet has higher reliability, safety and interchangeability, is more advanced switch cabinet, the current production of switch cabinet, most of the drawer type switch cabinet. They are suitable for industrial and mining enterprises and high-rise buildings that require higher reliability of power supply, and serve as distribution centers of centralized control.
(4) power and lighting distribution control box. Mostly closed vertical installation. Due to the use of different occasions, shell protection level is different. They are mainly used as power distribution devices on the production site of industrial and mining enterprises.
Computer room power distribution cabinets, power distribution box will often appear some problems, which are the root of most problems during the installation process improper operation, lead to frequent problems have serious consequences, how much is the installation of power distribution cabinets, power distribution box "taboo" and bad place to need to pay attention to understand distribution cabinets, distribution box installation specification and use the security issues is a qualified electrical technicians should have basic skills.
When installing the power distribution cabinet, we need to pay attention to the following five requirements:
1, the installation location selection problem, we in the process of the actual installation, if the location of the power distribution cabinet is not very perfect, or with the actual site requirement is at the same time, the installation personnel should submit revisions in a timely manner to the design unit, and shall be carried out according to construction drawing comprehensive conception by the designer or work site to the actual investigation, and need to meet the actual demand at the same time also can't affect beautiful, determine the actual installation location of the power distribution cabinet.
2, according to the actual demand to determine the reasonable installation position, specifications to determine the installation height and installation of power distribution cabinet, is a qualified electrical technicians should have basic skills, according to the specification of distribution ark bottom position general is 1.4 m high from ground, also visible the actual operation and convenient maintenance, and after the units to design the appropriate increase or reduce the installation height.
The installation height of large-area multi-distribution cabinet in the same place should be unified, the installation of distribution cabinet must be smooth, firm, horizontal deviation should not be too large, the connection between the inlet and outlet pipe of bright assembly electrical cabinet and distribution cabinet should be tight, firm, delicate, beautiful.
3, wires connected tightly and firm, cabinet has a safe and reliable neutral wire terminals and ground wire terminals, power distribution ark inside connection wires, power supply into line and load line connection with electrical components must be tight and firm, not loose, wire stripping length should be appropriate, conductor is not exposed, pressure to close, power distribution cabinet shall have complete neutral line by line terminal, the protection of the body must have a solid and reliable grounding terminals.
According to the specification: the wire and the electrical components must be connected with a spring washer and press firmly.
4. Select the color of the wire according to the specification. When wiring in the three-phase power distribution cabinet, the color of the wire shall be selected according to the specification for the power supply inlet line, load outlet line and connection line of the electrical components in the cabinet. That is, phase A is yellow, phase B is green, phase C is red, and the neutral line is light blue or black. The ground wire is yellow/green double-color wire. It is forbidden to use yellow/green double-color wire as other wires. The connection of the incoming and outgoing lines in the box should be fine and closely arranged.
The connecting wires of the electrical components should be arranged horizontally, horizontally and vertically, neat and beautiful. The bending radius of the corner should not be less than 6 times of the outer warp of the wires.
5. Keep the inside and outside of the box clean, and clearly mark the number of distribution cabinet. After the installation of the distribution cabinet, the sundry materials should be removed and kept clean and tidy. The purpose and serial number of the electrical circuit should be clearly marked on the distribution cabinet surface for future maintenance.
