The distribution box is called a distribution cabinet, mainly used for controlling and distributing electrical equipment, and for protecting the circuit from overload, short circuit, and leakage. The distribution cabinet includes wiring terminals, protective equipment, various switches, measuring equipment, and measuring equipment, which are widely used.
Mainly used for control, monitoring, measurement, and protection of power lines and major electrical equipment. It is often installed in substations, distribution rooms, and other occasions. So what are the incoming and outgoing methods of the distribution cabinet? What precautions should be taken? Next, we will introduce the cable tray factory to you.
The incoming and outgoing methods of the distribution cabinet:
There are various ways of incoming and outgoing lines in the distribution cabinet, including top in and bottom out, bottom in and top out, side in and top out, side in and bottom out, etc;
1. The specific form selection depends on whether the incoming cabinet is combined with the upper section cabinet, which is side entry;
2. If the upper cabinet is not a combined cabinet, then use a cable or bus bridge; The cable can be fed up or down, so the bus bridge needs to be fed up;
3. The outgoing mode shall be selected according to the project requirements. If there is a cable trench, the outgoing mode shall be downward, and if there is a cable tray, the outgoing mode shall be upward; (depending on the situation)
(1) Incoming method: The location of the entrance where the current flows into the distribution cabinet determines the incoming method. For example, if the current flows in from the top of the cabinet (usually through the bus duct), it is called incoming; What flows in from the bottom of the cabinet is called downflow (this method usually uses cables to draw current); The flow in from the cabinet side is called side entry (this method is generally used when the incoming cabinet and transformer are adjacent, etc.).
(2) Outlet method: The outlet where the current flows out of the distribution cabinet determines the outlet method. As mentioned above, there are generally only two methods: upper outlet and lower outlet.
Precautions for incoming and outgoing lines of distribution cabinets:
When calculating the cable length from the distribution cabinet to the distribution cabinet, how do you consider where the distribution cabinet enters and exits?
Based on experience, generally speaking, if there is no cable trench set up, most of the distribution panels and cabinets come out from the top, which is particularly evident in the distribution room. If it is a distribution box, it usually comes out from the bottom of the box.
When calculating the cable length from the distribution cabinet to the distribution cabinet, it should be considered to extend it by 2 meters. The distribution cabinet is usually equipped with incoming and outgoing lines at the bottom of the distribution cabinet.
The TN-C-S system usually uses the incoming distribution box as the dividing point between TN-C and S, with 4 incoming lines and 5 outgoing lines. N and PE merge in front of the distribution box and are called PEN lines, which are separated and no longer in contact after the distribution box. The N wire is no longer grounded, and the PE wire can only be connected to the metal shell of the electrical equipment, not to the neutral wire. It can be grounded in multiple places and also connected to a total equipotential connection.
The TN-C-S system can of course enter four out five, and PEN is divided into N and PE for household grounding. One point to emphasize is that these two lines cannot be merged in the future, and from this distribution box onwards, it can only be the TN-S system.
That's all for the introduction and related precautions of the power distribution cabinet. Do you have any new understanding of this? Welcome to our website and us http://www.sddlqj.cn Let's communicate together!