HUARUI 
MNS Low Voltage Switchgear Cabinet
The MNS low voltage draw-out type switchgear is a modular low voltage switchgear assembled in the factory using standard modules (hereinafter referred to as the "device"). Its technical specifications comply with IEC 439 "Low Voltage Switchgear and Controlgear Assemblies" and GB 7251 "Low Voltage Switchgear and Controlgear Assemblies" standards. It is suitable for power conversion, distribution, and control in power systems with an AC frequency of 50-60Hz and a rated working voltage up to 660V AC. It is widely used in various applications, including:
➤Power plants and substations
➤Petrochemical, metallurgical, steel rolling, light industry, textile, and other industrial and mining enterprises
➤Residential communities and high-rise buildings
The basic framework of the device is a modular assembly structure. All structural components of the framework are galvanized and fastened together using self-tapping locking screws or grade 8.8 vertical angle screws to form the basic framework. According to different scheme requirements, corresponding doors, closing plates, partitions, mounting brackets, as well as busbars, functional units, and other components are added to assemble a complete device. The dimensions of components and compartments within the device are modularized (module unit E = 25mm, the same below).
The PC is divided into four compartments:
Horizontal Busbar Compartment: Located at the rear of the cabinet
Functional Unit Compartment: Located at the upper front part or left front side of the cabinet
Cable Compartment: Located at the lower front part or right front side of the cabinet
Control Circuit Compartment: Located at the upper front part of the cabinet
Separation Measures: The horizontal busbar compartment is separated from the functional unit compartment and cable compartment by melamine phenolic sandwich panels or steel plates. The control circuit compartment is separated from the functional unit compartment by flame-retardant polyurethane foam plastic molded covers.
Vertical Busbar Rated Working Current:
Draw-out type MCC for single-sided or double-sided operation: up to 800A
Removable (fixed) type: up to 1000A
MCC for single-sided operation with cabinet depth of 1000mm: 800-2000A
|
Parameter name |
Unit |
Value |
|
|
Model |
|
MNS series (customization supported) | |
|
Rated working voltage |
V |
380 660 |
|
|
Maximum insulation voltage |
V |
660 |
|
|
Rated working current |
Horizontal busbar |
A |
630~5000 |
|
Vertical busbar |
A |
1000/MAX |
|
|
Busbar withstand current |
KA/1s |
50~100 |
|
|
Busbar peak current |
KA |
250 Effective value |
|
|
Short time peak current of vertical bus |
Standard type |
KA |
90 Maximum |
|
Reinforced type |
KA |
130 Maximum |
|
|
Shell |
Enclosure protection class |
/ |
IP130 IP40 |
|
Overall dimension (W*H*D) |
mm |
(600~1000)*2200*(600~1000) |
|
Enclosure
Made of aluminum-zinc plated steel plate with C-section framework and 25mm modular structure. Divided into busbar compartment, draw-out unit compartment, cable compartment, and auxiliary terminal compartment. High strength and corrosion resistance.
Draw-out Unit
Modular draw-out structure with three positions: connected, test, and disconnected. Units of the same specification are fully interchangeable, facilitating easy maintenance and quick replacement.
Primary Conductive Circuit
Includes horizontal busbar, vertical busbar, and outgoing terminals. All connection points are silver-plated to reduce contact resistance and ensure current-carrying capacity.
Instrument Transformers
Includes current transformers and voltage transformers, installed in the cable compartment or incoming cabinet, used for measurement, protection, and providing voltage signals.
Earthing Protection System
Main earthing busbar runs through the entire cabinet, with independent earthing terminals for each unit. Draw-out units maintain earthing continuity in all three positions.
Intelligent Measurement and Control Devices
Includes smart instruments, motor protectors, and communication modules, enabling measurement, protection, and remote monitoring functions.
Interlocking Mechanism
Draw-out unit position interlock and operating handle interlock, preventing insertion or withdrawal under load and preventing entry into live compartments, eliminating misoperation.
Pressure Relief and Protection Devices
Pressure relief channels are provided at the top of the busbar and cable compartments, directing high-pressure gases away during faults. Maximum protection level IP54.
1. Core Product Advantages
Modular Design, Flexible Configuration: Based on a 25mm module, it can be flexibly configured into different solutions to meet various power distribution requirements. Draw-out units have uniform specifications with strong interchangeability, facilitating easy expansion and modification.
Compact Structure, Space Saving: Uses standardized draw-out units, with a single cabinet accommodating up to 36 circuits, significantly saving floor space in the distribution room and reducing civil construction costs.
Safe and Reliable, Fault Isolation: Each functional compartment is independently separated to prevent fault spread between compartments. Pressure relief channels direct arc energy away, ensuring personnel safety. Maximum protection level IP54.
Strong Interchangeability of Draw-out Units: Draw-out units of the same specification are fully interchangeable. In the event of a fault, power can be restored by directly replacing the faulty unit with a spare one, eliminating the need for power outage repairs and reducing downtime.
Complete Mechanical Interlocking: Draw-out units have three positions (connected, test, disconnected) with clear position indication and locking. Reliable interlocks between the operating handle and positions prevent incorrect operation.
High Current Carrying Capacity: Horizontal busbar current up to 6300A, with short-time withstand current up to 100kA, meeting the demanding requirements of high-capacity power distribution and high short-circuit current systems.
Convenient Maintenance, Low Operating Cost: The draw-out structure facilitates easy maintenance and replacement. Standardized parts have strong interchangeability, reducing spare parts inventory pressure and lowering operating costs.
High Intelligence Level: Can be equipped with smart instruments, motor protectors, and communication interfaces, enabling remote monitoring, fault alarm, and energy consumption management, adaptable to digital power distribution systems.
2. Service Life
Under standard operating conditions and proper usage, the overall design service life of the MNS low voltage switchgear can reach 20 to 25 years. The enclosure, made of aluminum-zinc plated steel plate with a C-section framework, offers excellent corrosion resistance and can achieve a service life of over 30 years. The draw-out unit insertion mechanism has a mechanical life of more than 5,000 operations, and units of the same specification are fully interchangeable. The circuit breaker has a mechanical life of 10,000 to 20,000 operations. Instrument transformers have a service life of 15 to 20 years, while smart instruments and protection devices have a service life of approximately 10 to 15 years.
1. Daily Maintenance
Environment and Appearance Inspection: Weekly check whether the cabinet surface is deformed or rusted, observe whether there are foreign objects or water accumulation inside the cabinet, and whether the temperature and humidity of the distribution room are within specified ranges.
Operating Parameter Monitoring: Observe whether current and voltage readings of each draw-out unit are normal, whether indicator lights and instruments display correctly, and whether there are any abnormal alarm signals.
Draw-out Unit Inspection: Monthly check whether the draw-out unit handle is in place, whether the position indication is accurate, whether insertion and withdrawal operations are smooth, and whether units of the same specification interchange properly.
Tightening Inspection: Every six months check whether busbar connection bolts, incoming/outgoing terminals, and earthing wires are loose, and whether secondary circuit terminals are secure.
Earthing System Inspection: Every six months check whether the main earthing busbar and earthing terminals of each unit are reliably connected, and that the earthing resistance meets requirements (≤4Ω).
Preventive Testing: Perform preventive testing every 1 to 3 years, including insulation resistance testing, loop resistance testing, and protection device setting verification.
2. Safety Regulations
Power-Off Operation Principle: Before starting work, confirm that the draw-out unit is in the disconnected position or that the upstream power supply is disconnected. Strictly follow the procedures of power cut, voltage verification, and earthing wire installation.
Draw-out Unit Operation Standard: It is strictly prohibited to withdraw or insert a draw-out unit under load. Position switching can only be performed after the circuit breaker is open. Maintain correct standing position during operation.
Voltage Verification and Earthing: Before entering the cable compartment or contacting conductors, use a voltage detector to verify the absence of voltage. Only after confirmation of no voltage may work begin. Install earthing wires where necessary.
Personal Protective Equipment: Operators must hold valid certificates and work in compliance with regulations. Wear insulated shoes and insulated gloves, and stand on an insulating mat during operation.
Draw-out Unit Replacement Procedure: Before replacing a faulty draw-out unit, confirm that the spare unit has the same specifications. Pull the faulty unit to the disconnected position, remove it, insert the spare unit, and push it to the connected position.
Maintenance Record Requirements: After each maintenance operation, complete maintenance records including maintenance date, maintenance content, problems found, and handling results. Establish equipment files.
① Power Plants: Auxiliary power distribution systems
② Substations: Power receiving and distribution
③ Industrial and Mining Enterprises: Industrial power distribution and motor control in petroleum, chemical, metallurgy, etc.
④ Infrastructure: Airports, docks, railway stations, radio and television centers
⑤ Building Sector: High-rise buildings, commercial complexes, data centers
⑥ New Energy: Photovoltaic and energy storage system integration
1. Environmental Risks
1. Moisture and Condensation Risk: High humidity causes condensation on insulation parts inside the cabinet, reducing insulation resistance and easily leading to surface flashover or creepage discharge.
2. Dust Contamination Risk: Conductive dust accumulates on insulators and contact box surfaces, shortening creepage distance and possibly causing short circuits or partial discharge.
3. High-Temperature Overheating Risk: Poor ventilation or excessive ambient temperature causes the temperature rise inside the cabinet to exceed limits, accelerating insulation aging and component damage.
4. Vibration Impact Risk: Proximity to large vibrating equipment may cause fasteners to loosen and the truck position to shift, affecting interlock reliability.
2. Installation Restrictions
1. Ambient Air Temperature: Not higher than +40°C and not lower than -5°C, with an average temperature over any 24-hour period not exceeding +35°C.
2. Atmospheric Conditions: Clean air. Relative humidity shall not exceed 50% at a maximum temperature of +40°C. Higher relative humidity is permitted at lower temperatures, for example 90% at +20°C, but due consideration should be given to the possibility that moderate condensation may occasionally occur as a result of humidity variations.
3. Altitude: Not exceeding 2000m.
4. Transport and Storage Conditions: The device is suitable for transport and storage within a temperature range of -25°C to +55°C. Short-term exposure (not exceeding 24 hours) up to +70°C is permitted. Under these extreme temperature conditions, the device shall not suffer any irreversible damage and shall be capable of normal operation under normal conditions.
5. Non-Standard Conditions: If the above operating conditions cannot be met, the matter shall be resolved through negotiation between the user and the manufacturer.
6. Special Applications: When the device is to be used in offshore oil platforms and nuclear power plants, a separate technical agreement shall be signed.
Due to the unique characteristics of the cabinet, the quotation for this product requires certain technical parameters. Full-dimensional personalized customization is also supported. The main ordering instructions are as follows:
1. Main circuit scheme and single-line system diagram;
2. Schematic diagram or wiring diagram of the secondary circuit;
3. Arrangement diagram of the switchgear and layout plan of the distribution room;
4. Detailed specifications and quantities of all electrical equipment installed in each switchgear unit;
5. Provide the working current and short-circuit current of the horizontal busbar. Busbar specifications shall be selected according to the factory standard (factory standard busbar specifications: 10×30×2; 10×60×2; 10×80×2; 10×60×4; 10×80×2×2; 10×60×4×2). If busbar specifications are not specified, they shall be determined by the manufacturer; For the busbar system L1, L2, L3, PE or L1, L2, L3, PEN, if not specified, it shall be determined by the manufacturer;
6. Provide the operating name for each circuit (limited to 10 characters). If not provided, the manufacturer shall supply blank symbol plates;
7. Protection level of the switchgear enclosure (IP30, IP40) and whether the bottom of the cabinet is to be sealed. If not specified, the protection level shall be IP30 with the cabinet bottom unsealed;
8. Color of the switchgear surface paint. If not specified, it shall be beige gray (米灰色).
