Distribution box is a massive parameter in data, which generally constitutes a low-voltage forest according to electrical wiring. It is required to assemble switchgear, measuring instruments, protective appliances and auxiliary equipment in a closed or semi-closed metal cabinet or screen to form a low-voltage distribution box. During normal operation, the circuit can be turned on or off by manual or automatic switch.
The distribution box has the characteristics of small volume, simple installation, special technical performance, fixed position, unique configuration function, no limitation of the site, relatively universal application, stable and reliable operation, high space utilization rate, less land occupation and environmental protection effect.
The distribution box has the characteristics of small volume, simple installation, special technical performance, fixed position, unique configuration function, no limitation of the site, relatively universal application, stable and reliable operation, high space utilization rate, less land occupation and environmental protection effect. It is the control center that commands various components in the power supply line to distribute electric energy reasonably, the control link that reliably receives the upper power supply and feeds out the load electric energy correctly, and the key to obtain the satisfaction of users with the power supply quality. Improving the operation reliability of power distribution box is the goal of creating high-quality projects.
Purpose of distribution box: to distribute electric energy reasonably and facilitate the opening and closing operation of the circuit. It has a high level of safety protection, and can directly display the on-state of the circuit.
principle of operation
It is convenient for management and maintenance when circuit failure occurs. Distribution box and distribution card of distribution cabinet are complete sets of devices for centralized installation of switches, instruments and other equipment.
There are two kinds of commonly used distribution boxes, wooden and iron. Now, the electricity consumption everywhere is quite large, so iron is used more. The purpose of the distribution box: of course, it is convenient to stop and send electricity, and it plays the role of measuring and judging the stop and send electricity. classify
(1) Fixed panel switchgear, often called switchboard or distribution panel. It is an open switch cabinet with a panel cover, which has a protective effect on the front, and the back and sides can still touch the live parts, so the protection level is low. It can only be used in industrial and mining enterprises with low requirements on power supply continuity and reliability, and can be used for centralized power supply in transformer rooms.
(2) Protective (i.e. enclosed) switchgear refers to a low-voltage switchgear with all sides closed except the installation surface. The electrical components such as switch, protection, monitoring and control of this cabinet are all installed in a closed shell made of steel or insulating material, which can be installed reliably on or off the wall. Each loop in the cabinet can be isolated without isolation measures, or it can be isolated by grounded metal plate or insulation board. Usually, the door is mechanically interlocked with the main switch operation. In addition, there is a protective table-type switchgear (console), and the panel is equipped with electrical appliances such as control, measurement and signal. Protective switchgear is mainly used as power distribution device in process site.
(3) Drawer switch cabinet. This kind of switchgear adopts a closed shell made of steel plate, and the electrical components of the incoming and outgoing circuits are all installed in drawable drawers, which constitutes a functional unit that can complete a certain type of power supply task. The functional unit is separated from the bus or cable by a grounded metal plate or a functional plate made of plastic to form three areas: bus, functional unit and cable. There are also isolation measures between each functional unit. Drawer-type switchgear has high reliability, safety and interchangeability, and is an advanced switchgear. At present, most of the switchgear produced are drawer-type switchgear. They are suitable for industrial and mining enterprises and high-rise buildings that require high reliability of power supply as centralized control distribution centers.
(4) Power and lighting distribution control box. Mostly closed vertical installation. Due to different use occasions, the protection level of the shell is also different. They are mainly used as power distribution devices in production sites of industrial and mining enterprises.
According to the drawing marked in the Distribution Box System Diagram.
In NPX630/3P 400A, NPX630 is the model of breaker, 3P is three-pole, and 400A means the maximum breaking current is 400A. NPX160/3P160A WL1YJV-4 * 70+1 * 35-SC80FC58.8W AP3 Distribution box: NPX160 is the model of breaker.
3P refers to three poles, rated frequency is 50Hz, rated isolation voltage is 690V, and tripping current is 40-160A. WL1: refers to loop 1. There are loops 2 and so on behind. YJV: Copper Core XLPE Cable. NHYJV: fire-resistant copper-core XLPE cable
4*70+1*35: refers to the cross section of 4 cores of 70mm2.
Add a neutral core with a core section of 35. SC80 refers to the welded steel pipe (commonly known as black iron pipe) with a diameter of 80. FC: refers to the underground application in the ground.
C65N-C10/1pwl1bv-3 * 2.5-sc15cc0.78kw lighting: C65n is the breaker model.
C10/1P: The maximum breaking current of the breaker is 10A, and the number of poles is one. BV: Copper Core PVC Insulated Cable
3 * 2.5: The cross-sectional area of 3 cores is 4mm2.
SC15: pass through a steel pipe with a diameter of 15mm; CC: be buried in the roof or roof.
C65n-C16/3pwl5bv-4 * 4-sc20fcw3.7kw 380v air conditioning socket:
In loop 5, the breaker model is C65N, the maximum breaking current is 16A, and the cross section of 4 cores is 4mm2.
The copper-core PVC insulated cable is directly laid in the ground and in the wall through a 20mm steel pipe.
In addition:
Various laying methods:
AB- Laying along or across beams (roof trusses)
BC- Buried in the beam
AC- laying along or across columns
CLC- Buried in the column
WS- laying along the wall
WC- Buried in the wall
CE- Laying along the ceiling or top panel
CC- concealed laying in the roof or roof.
SCE- Laying in suspended ceiling
FC- Floor or underground laying
SC- Laying through welded steel pipes
MT- laying through electric conduit
PC- laying through hard plastic pipe
FPC- Laying through Flame Retardant Semi-rigid PVC Pipe
CT- cable tray laying
MR- metal trough laying
M- laying with steel cables
KPC- Laying corrugated conduit through PVC plastic
CP- Laying through metal hose
DB- direct burial
TC- cable trench laying
CE- concrete pipe laying.
Trip mode:
MA- magnetic trip
TM- Thermomagnetic Trip
MIC- electronic trip
Breaking capacity:
The breaking capacity is divided into five grades:
F:36KA
N:50KA
H:70KA
S:100KA
L:150KA
Distribution system diagram in CAD
What do BVV-500(2×2.5)WC.CEC and ZR-BVV-500(2×4+1×2.5)WC.CEC stand for? What does BVV-500 (2×2.5) WC. CEC Zr-BVV-500 (2×4+1×2.5) WC. CEC stand for respectively?
The first one is about two 2.5 square plastic copper wires.
The second is to say that two square+plastic copper wires are a 2.5 square.
What do C65N-32A/2P ZR-BVV-3X4 in the electrical system diagram respectively mean? C65N- switch model (maximum breaking current is 65A) 32A- rated breaking current (breaking current of this switch is 32A) 2P- series.
ZR- conductor type (ZR stands for flame retardant)
BVV-BVV copper core round PVC insulated PVC sheathed wire 3X4-3 4mm2 wires
The meaning of C65N-C63/3P and DPN-C32/2P in the distribution box of electric drawing.
DPN: It’s a series of DPN circuit breakers, C32/2P: It’s a two-phase 32A base circuit breaker, and the difference between electric current 32A. BVV.BVVB wires. What kind of wires is Zr-BV? Can it be replaced by BVR?
The difference between BVV and BVVB wires is that BVV wire is a round wire with copper-core PVC insulation and PVC sheath, while BVVB is a flat wire with copper-core PVC insulation and PVC sheath. The difference between them is that the cross section is different. ZR-BV is a flame-retardant copper-core PVC insulated wire, while BVR is a copper-core PVC insulated flexible wire. You can see what you are using it for, and if it has flame retardant effect, it can’t be replaced.
BVV.BVVB is a sheathed copper-plastic wire, the former is round and the latter is flat. Zr-BV is a flame-retardant copper-plastic wire (no sheath, only insulation).
When there is no flame retardant requirement, BVR can replace Zr-BV, but it is not cost-effective, and BVR is relatively expensive.
Excuse me, among the wires and cables, "BV, BLV, BVVB, BVR, RV, RVS, RVV, QVR, AVVR, VV, VLV" are commonly used wires. BV, BVR, RV, RVV are not those used in large-section projects.
Series B belongs to wiring, so it starts with B, and the voltage is 300/500V V.
V is PVC and polyvinyl chloride, which is (plastic)
L is the code for aluminum core.
R means (soft). To be soft is to increase the number of conductors.
BV copper-core PVC insulated wire
BLV aluminum core PVC insulated wire
BVR copper core PVC insulated flexible wire
The above wire structure: conductor+insulation
Take 2.5mm2 as an example:
BV is one with a diameter of 1.78mm and seven with a diameter of 0.68.
BLV is a piece with a diameter of 1.78 mm.
BVR is 19 pieces with a diameter of 0.41 mm.
RV copper core PVC insulated flexible wire
Is it softer than BVR, or 2.5 is 49 0.25mm copper wires?
RVV copper core PVC insulated PVC sheathed flexible wire
There is one more plastic sheath than RV.
In addition: our most commonly used "sheath line"
BVVB copper core PVC insulated PVC sheathed flat cable
Just two BV wires, with a white sheath.
RVV and AVVR are soft copper core PVC insulated PVC sheathed cables.
Look at JB8734-1998
SYV stands for coaxial cable
1. Usage code-not marked as power cable, k as control cable and p as signal cable;
Second, insulation code-Z oil-immersed paper, X rubber, V PVC, YJ crosslinked polyethylene
Third, the conductor material code-not marked as copper, L is aluminum;
Iv. code of inner sheath-q lead package, l aluminum package, h rubber sleeve and v PVC sheath.
V. Derived code-D does not drip, and P is dry insulated;
Six, the outer sheath code-(represented by numbers, too much, too lazy to write)
Seven, special product code-TH humid tropical zone, TA dry tropical zone;
dash
Eight, rated voltage-unit KV pressure relief orifice
First, the principle and scope of application: first. The main working principle of pressure relief orifice plate is to reduce the pressure of fluid power. When flowing water passes through the pressure relief orifice, head pressure drop (head loss H) occurs at the pressure relief orifice due to local resistance loss. Therefore, the outlet pressure and outlet flow of automatic sprinkler equipment and fire hydrants at the bottom can be reduced. Because there are many stories in high-rise buildings, the hydrostatic pressure borne by the high and low stories is different, and the actual water output is quite different. When acting, the water output of automatic sprinkler equipment and fire hydrants at the bottom far exceeds the design flow of the top story. Compared with the pressure reducing valve, the pressure reducing orifice plate has the advantages of simple system, less investment and convenient management. However, the pressure relief orifice can only reduce the dynamic pressure, but not the static pressure, and the downstream pressure varies with the upstream pressure and flow rate, which is not stable enough. In addition, the pressure relief orifice plate is easy to block. It can be used under the condition of good water quality and stable water supply pressure. The working principle of decompression orifice plate is to decompress the dynamic pressure (excluding static pressure) of liquid. At present, high-rise buildings have more floors. The hydrostatic pressure on the upper and lower floors is different. When the water comes out, the water flow pressure in the lower layer is much higher than that in the upper layer. When putting out a fire, the low-level fire hose often bursts. This series of pressure-reducing orifice plates have the function of reducing the dynamic pressure of water flow. When the flowing water passes through the pressure relief orifice, the pressure drop occurs at the pressure relief orifice due to local resistance loss, thus meeting the needs of outlet pressure and flow of the fire hydrant.
Code for design of automatic sprinkler system gb 50084—2001 II. The decompression orifice plate shall meet the following requirements:
1 should be located in a horizontal straight pipe section with a diameter of not less than 5omm, and the length of the front and rear pipe sections should not be less than 5 times the diameter of the pipe section;
2 orifice diameter should not be less than 30% of the diameter of the set section, and should not be less than 20mm；;
3 should be made of stainless steel plate with a thickness of more than 3 mm.
4 The upper edge and the lower edge of the axis perpendicular to the ground of the pressure relief orifice plate shall be provided with a φ10mm hole for exhaust and drainage.
(1) In order to overcome the non-uniformity of water spraying, the pressure reducing device should adopt pressure reducing orifice plate instead of pressure reducing valve. Because the pressure reducing valve needs to add a filter in front of the valve, it is only suitable for the vertical partition pressure reduction of the spray system in front of the wet alarm valve;
(2) The pressure-reducing orifice plate is mainly used to overcome the vertical water spraying unevenness of the sprinkler system caused by geometric height difference and head loss of the sprinkler riser, and its position is located at the starting end of each layer of water distribution pipe or water distribution main pipe, generally behind the safety signal valve;
(3) The pressure relief orifice plate should not be set on the water distribution branch pipe. Because the specification stipulates that the pressure relief orifice plate should be set on the horizontal pipe section with a diameter of not less than 50 mm. If the diameter of the water distribution branch pipe is greater than or equal to 50 mm, there are generally more nozzles on the branch pipe.
MHYBV Mine Cable Specification MHYBV- Mine Detection Cable Wholesale Langfang MHYBV Cable Dealer
Our company specializes in producing all kinds of VVRP soft-core shielded cables with good quality and low price. We hope new and old customers will call us for advice.
Application: It is suitable for carrying electric energy in power lines with constant voltage of 0.6/1kV and below for VVRP cables. This product has the characteristics of strong anti-electromagnetic interference, lightning strike resistance and uniform electric field, and improves the quality of power supply. The external adapter has the occasion of precision electronic installation, such as computer center, aerospace monitoring center, intelligent building and so on.
Let’s get to know something about VVRP cable first! Cable Product Title: Metal Shielded Power Cable Execution Scale: This product is designed and manufactured according to enterprise scale.
Structure description: MHYBV mine cable specification MHYBV- mine detection cable wholesale Langfang MHYBV cable dealer
Product use: It is suitable for transporting electric energy in power lines with rated voltage of 0.6/1kV and below. This product has the characteristics of strong anti-electromagnetic interference, lightning strike resistance and uniform electric field, and improves the quality of power supply. The external adapter has the occasion of precision electronic installation, such as computer center, aerospace monitoring center, intelligent building and so on.
1. Conductor
2, PVC(XLPE) insulated MHYBV mine cable specifications MHYBV- mine detection cable wholesale Langfang MHYBV cable dealer
3. Belt (if any)
4. PVC inner sheath
5, metal shielding
6. PVC outer sheath
Description of the model of the metal shielded power cable: The metal shielded power cable is only different from the XLPE insulated power cable and PVC insulated power cable in design structure, and it is distinguished by the suffix "-p" in the model, such as: VV-P, YJV-P, YJLV22-P and so on.
Usage characteristics: item performance
Rated voltage Uo/U 0.6/1kV
Long-term allowable working temperature These functions are consistent with the corresponding PVC insulated power cable or XLPE power cable.
Insulation function
Minimum temperature during short circuit
Impedance has low and uniform positive (reverse) sequence and zero sequence working impedance, which is beneficial to improve power supply quality.
The reactance of concentric conductor is much higher than that of ordinary four-core cable in zero-sequence working mode, which is beneficial to the sensitive action of short-circuit active protection installation, thus ensuring the safe operation of related equipment
Anti-interference ability has strong anti-electromagnetic interference and lightning protection functions.
This time for Wanxiang Electric Vehicle Co., Ltd. to eliminate MHYBV mine cable specification MHYBV- mine detection cable wholesale, the VVRP paid by Langfang MHYBV cable distributor is mainly single core, the copper wire is tinned copper wire, the shielding layer is also tinned wire, and the sheath is flame retardant PVC. The difference between VVP and VVRP is that VVP uses hard copper wire, while VVRP, mainly R, R stands for soft, so copper wire is very thin, easy to bend and convenient to use in workplace.
Main points of power cable model expression: insulation code (YJ) stands for: XLPE insulation; Sheath code V (PVC sheath) and E (low-smoke halogen-free polyolefin sheath); Structural characteristics: P (copper wire or tinned copper wire), P2 (copper tape winding), P1 (copper wire winding), P3 (aluminum-plastic composite tape winding); Flame retardant code: ZR (flame retardant), WDZ (low smoke and halogen-free flame retardant)