Low Voltage Switchgear & Distribution Panels
The Main Distribution Board (MDB) is a panel or enclosure designed to house fuses, circuit breakers, and residual current protection devices. It contains the necessary components to distribute electrical power to individual circuits or end-user points. Electrical power is supplied to the MDB from a transformer or an upstream distribution panel.
An MDB typically features one or more incoming power supplies and includes a main circuit breaker, residual current device (RCD) or earth leakage protection. It is composed of an independent enclosure, a busbar system, Molded Case Circuit Breakers (MCCBs), metering devices, auxiliary components, and corresponding current transformers. The internal layout follows a systematic configuration, clearly separating incoming and outgoing sections for safe and efficient power distribution.
The Main Distribution Board (MDB) serves as the central hub of your electrical infrastructure—the “nerve center” of power distribution. Engineered to handle currents of up to 6300A, our MDBs are designed for high breaking capacity systems, ensuring stable, uninterrupted power supply for demanding applications such as factories, high-rise buildings, and large commercial or industrial facilities.
1. Robust Short-Circuit Protection (Up to 100kA)
Safety is non-negotiable. Our cabinets are tested for high Short-time Withstand Current (Icw). Whether it's a 50kA or 100kA requirement, our structures are reinforced to withstand the thermal and mechanical stresses of a major electrical fault.
2. High-Purity Copper Busbar System
We use 99.9% pure electrolytic copper for our busbars. This ensures minimum heat dissipation and maximum conductivity, significantly reducing energy loss and preventing premature component aging due to overheating.
3. Modular & Scalable Construction
Following the design principles of the world's leading switchgear, we offer:
Withdrawable Units (Draw-out): Swap out breakers in seconds without a total blackout.
Custom Form of Separation: Available in Form 2, Form 3, or Form 4 to ensure maximum safety for maintenance personnel.
4. Advanced Surface Protection
Our enclosures are fabricated from 2.0mm-3.0mm premium cold-rolled steel. Each unit undergoes a strict 7-tank pretreatment process before being finished with high-durability Epoxy Polyester Powder Coating (RAL 7035) for superior corrosion resistance.
Detailed Technical Specifications
Parameter Category | Technical Specifications |
Rated Characteristics | Rated Current: 400A, 630A, 800A, 1000A, 1250A, 1600A, 2000A, 2500A, 3150A, 4000A, 5000A, 6300A |
Short-circuit Performance | Rated Short-time Withstand Current: 50kA-100kA/1s |
Protection Degree | IP31, IP41, IP42, IP54 (Optional) |
Enclosure Material | 2.0-3.0mm premium cold-rolled steel |
Construction Types | Fixed, Plug-in, Withdrawable (Can be mixed configuration) |
Busbar System | Horizontal Busbar: Copper or aluminum (According to current rating) |
Compliance Standards | IEC 61439-1/-2, GB 7251.1, UL 508A |
Key Product Features
1.Modular Flexible Design
Standardized modular structure supporting multiple functional unit combinations
Expandable design for future capacity increase and modification
Multiple installation methods: Wall-mounted, Free-standing, Cabinet combination
Flexible cable entry/exit: Top entry/exit, Bottom entry/exit, Side entry/exit
2.High Reliability Protection System
Main circuit breaker protection: Air circuit breaker or moulded case circuit breaker
Graded protection: Coordinated protection devices at all levels
Overload and short-circuit protection: Precise protection characteristic curves
Earth fault protection: Complete earthing system design
3.Intelligent Monitoring Functions
Energy management: Integrated energy meters for consumption monitoring
Status monitoring: Real-time monitoring of electrical parameters and equipment status
Remote control: Support for remote operation and automatic control
Data communication: Multiple communication protocols (Modbus, Profibus, Ethernet, etc.)
4.Safety Protection Design
Five protection functions: Prevent misoperation and access to live compartments
Isolation design: Complete separation between functional units
Arc flash protection: Internal arc fault protection design
Emergency operation: Emergency trip and isolation functions
5.Quality Manufacturing Process
Precision machining: CNC equipment processing ensures dimensional accuracy
Strict inspection: Strict quality control at every process
Type testing: Full type test verification
Life testing: Mechanical and electrical life testing
Typical Applications
High-rise buildings: Main distribution systems for office buildings, hotels, apartment buildings
Industrial plants: Main distribution centers for manufacturing factories, production workshops
Commercial centers: Power distribution systems for shopping malls, supermarkets
Public facilities: Distribution systems for hospitals, schools, airports, stations
Infrastructure: Data centers, communication rooms, water treatment plants
Optional Configurations
Basic Type: Standard configuration meeting basic distribution requirements
Enhanced Type: Additional intelligent monitoring and protection functions
Custom Type: Customized design solutions based on special requirements
Explosion-proof Type: Suitable for explosive atmospheres
Outdoor Type: Fully sealed design for outdoor installation
Q1: What is the maximum current capacity of your Main Distribution Boards (MDB), and what standards do they follow?
A: Our customized Main Distribution Boards can be engineered to handle high current capacities up to 6300A. Every MDB is designed, manufactured, and rigorously tested in strict accordance with the IEC 61439-1 & 2 international standards to ensure optimal safety, reliability, and global compliance.
Q2: What "Forms of Internal Separation" can your factory provide for the MDB?
A: We understand that critical facilities require high safety during maintenance. We can manufacture MDBs with all forms of internal separation, from Form 2b for standard commercial buildings, up to Form 4b for critical infrastructure (like data centers and heavy industries). Form 4b ensures that busbars, functional units, and terminals are completely isolated from each other, maximizing operator safety.
Q3: Can we specify the brands of the main Air Circuit Breakers (ACB) and MCCBs in the MDB?
A: Absolutely. To ensure your system is serviceable globally and meets your consultant's specifications, we offer full flexibility in component selection. We regularly integrate top-tier international brands such as Schneider Electric, ABB, and Siemens. We can also provide high-quality, cost-effective Chinese tier-1 brands based on your project budget.
Q4: Do you offer custom engineering based on our project's Single Line Diagram (SLD)?
A: Yes, custom engineering is our core strength. You only need to provide your Single Line Diagram (SLD) and load schedules. Our experienced electrical engineers will calculate the short-circuit withstand current (Icw), design the copper busbar sizing, and create a complete 2D/3D CAD layout for your approval before production begins.
Q5: Can you integrate smart metering and APFC (Automatic Power Factor Correction) into the MDB?
A: Yes, we frequently design combined MDBs. We can seamlessly integrate digital multi-function meters, power quality analyzers (with RS485/Modbus communication for your BMS), and dedicated APFC sections with capacitor banks to improve your facility's energy efficiency and avoid utility penalties.
Q6: How do you ensure the heavy-duty copper busbars won't overheat under full load?
A: Thermal management is critical in our designs. We strictly use 99.9% pure electrolytic copper busbars. The cross-sectional area of the busbars is calculated conservatively to keep the temperature rise well below IEC limits. Additionally, our enclosures feature optimized ventilation (natural or forced cooling with exhaust fans) to dissipate heat effectively.
Q7: What kind of testing is done on the MDB before it is shipped internationally?
A: Before leaving our factory, every MDB undergoes a comprehensive Factory Acceptance Test (FAT). This includes rigorous visual inspections, mechanical operation checks of the breakers, continuity testing, and high-voltage dielectric (insulation) tests. We provide a detailed, stamped FAT report with every shipment.
Q8: MDBs are very large and heavy. How do you package them for safe ocean freight?
A: For large multi-column MDBs, we engineer the switchgear in modular shipping sections. Each section is vacuum-sealed in moisture-barrier bags with large desiccants, heavily padded with shock-absorbing materials, and packed inside custom-built, heavy-duty, fumigation-free wooden crates. The crates are reinforced with steel straps to endure rough handling and long-distance sea transit.
Q9: Do you provide installation support for overseas contractors?
A: While our MDBs are completely pre-wired and modularized for easy connection on-site, we provide extensive support. We supply comprehensive as-built drawings, detailed connection manuals, and clearly labeled terminal blocks. Our engineering team is also available for real-time remote video guidance during your on-site installation and commissioning phase.
Q10: What is the typical manufacturing lead time for a customized MDB?
A: Due to the highly customized nature of MDBs, the typical manufacturing lead time ranges from 4 to 8 weeks after the final approval of the structural and electrical drawings. We maintain strong supply chain relationships with global component brands to minimize delays and keep your project on schedule.
