Main Distribution Boards (MDBs) play a crucial role in any power system by distributing electricity from the transformer’s main supply to various circuits. Used across homes, offices, and industrial sites, these boards vary in size, capacity, and configuration. Before selecting one, it’s important to understand your system’s load requirements and ensure the MDB meets all safety and compliance standards.
Meshal Alghomiz is an electrical content writer with a background in Electrical Engineering and affiliation with the Technical and Vocational Training Corporation. He specializes in simplifying complex electrical concepts for technical audiences.
A Main Distribution Board (MDB) is the primary power distribution point in large buildings or industrial systems. It receives electricity from a transformer or main source and sends it to sub-panels or circuits. These panels include main circuit breakers, busbars, and surge protection devices. MDBs are crucial for power load management, fault isolation, and ensuring the safety of voltage distribution.
| Specification Panel Type | Details MDB (Main Distribution Board) & DB (Distribution Board) |
|---|---|
| Rated Current |
32A, 50A, 60A, 100A, 200A, 400A, 630A, 800A, 1000A * Panel size may vary depending on the environment |
| Rated Operating Voltage (Ue) | 600/690 VAC |
| Frequency | 50Hz / 60Hz |
| Rated Insulation Voltage (Ui) | 690 / 750V |
| Rated Impulse Withstand Voltage (Uimp) | 8kV |
| Rated Short-Circuit Breaking Capacity (Icu) | Up to 85kA |
| Metal Thickness | Up to 2.0mm |
| Metal Type | EGI (Electro Galvanized Iron) Sheet |
| Degree of Protection | IP3X (Indoor) ~ IP55 (Outdoor) |
| Color | RAL7032, RAL7035, RAL7033Z |
| Cable Entry | Top / Bottom |
| Installation Type | Indoor / Outdoor |
| Applied Standard | IEC 61439-1/2 |
| Form of Separation | Form 1 to Form 3B |
MDBs ensure efficient power distribution and protect circuits using built-in safety devices like circuit breakers, busbars, and meters. They help prevent overloads, short circuits, and electrical faults.
Before selecting an MDB, check the total power load, the number of circuits needed, and whether the panel meets Saudi and international safety standards. Choosing the right size and type ensures safe, long-term performance.
A Main Distribution Board (MDB) is used to receive electricity from the main power source, control it, and safely distribute it to different parts of a building. It protects circuits from overload and ensures efficient power delivery in homes, offices, factories, and other large facilities.
An MDB 2500 panel is built to handle up to 2500 amps of electrical current. It is designed for industrial energy control, protecting systems against overload, short circuits, or equipment damage. The MDB 2500 often features type-tested assemblies, 3-phase breakers, and compatibility with IEC 61439-1 standards. It’s widely used in large infrastructure projects like malls, hospitals, and manufacturing plants.
The cost of a 2500A MDB in Saudi Arabia varies based on brand, type testing, IP rating, and custom design.
Always compare specifications: enclosure material, busbar configuration, breaker capacity, and local compliance standards. For accurate pricing, request a custom quote from certified suppliers.
Main Distribution Boards (MDBs) come in various sizes, depending on the power needs, building type, and number of circuits. Here’s a simple breakdown:
In electrical diagrams or single-line diagrams (SLD), the Main Distribution Board (MDB) is shown using a standard symbol. This symbol helps identify where the main power is divided and sent to other circuits.
It usually appears as a rectangle with lines showing the incoming power and outgoing circuits. These symbols may change slightly depending on the drawing standards used, like IEC or ANSI.
Engineers and electricians use this symbol to plan, install, and troubleshoot electrical systems in homes, buildings, or factories.
The most common symbol for a Main Distribution Board (MDB) is a rectangular box labeled “MDB.” One thick line (incoming power) connects to the top or bottom, and several thinner lines (outgoing circuits) branch out.
This symbol shows that the MDB is the main point where electricity enters and then spreads to different parts of a building. It’s used in electrical drawings to help engineers and technicians plan and troubleshoot power flow easily.
In some IEC or architectural drawings, it may look like:
Or in circuit symbol form:
This includes miniature representations of circuit breakers inside.
Used in:
Important Notes
The main circuit breaker is the most critical component of a Main Distribution Board (MDB). It controls the incoming power supply and provides protection against overload or short circuits. Supporting components like busbars, breakers, and monitoring tools work together to ensure safe and efficient power distribution.
Component | Function |
Main Circuit Breaker | Controls and protects the main incoming power supply |
Busbars | Distribute power internally between connected breakers |
Outgoing Breakers | Deliver power to sub-panels or specific load areas |
Surge Protection Device | Safeguards against voltage spikes and lightning surges |
Meters & Indicators | Monitor voltage, current, and energy consumption |
Neutral/Earth Bars | Provide grounding and secure neutral wire connections |
CTs (Current Transformers) | Enable accurate current measurement for metering/protection |
Main Distribution Boards (MDBs) are engineered to meet varying electrical demands in residential, commercial, and industrial settings. Key specifications include:
MDBs are built to comply with international standards like IEC 61439-1, ensuring safe and reliable power distribution. Always select MDBs based on your project’s load requirements, safety needs, and environmental conditions.
MDB design includes an incomer breaker, busbars, outgoing breakers, grounding system, and metering, all enclosed in a safe, structured panel that distributes and controls power in large facilities.
Wiring an MDB must follow strict safety procedures and electrical code requirements. Here’s a simplified guide:
Only licensed professionals should handle high-current electrical panels.
MDBs are rated for higher current capacities, while SDBs are tailored for smaller, dedicated circuits. Both panels must comply with Saudi electrical safety standards and follow correct load segregation practices.
Main Distribution Boards (MDBs) are the backbone of electrical systems, ensuring safe and efficient power distribution. From their design and wiring to their role compared to Sub Distribution Boards (SDBs), understanding MDBs is crucial for any project. Choosing the right MDB tailored to your needs ensures long-term reliability, compliance with safety standards, and uninterrupted power supply.
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