# ABB MDmax ST Low-Voltage Switchgear – Engineered and Manufactured by Derun Electric, an ABB Authorized Partner

**Date: June 29, 2026**

In modern power systems, low-voltage switchgear serves as the core equipment for power distribution, control, and protection. Its reliability, safety, and flexibility directly impact the stability of the entire power network. The **ABB MDmax ST low-voltage switchgear** is precisely such a market-proven, technologically mature benchmark product.

As an **ABB Gold Partner and authorized manufacturer of the MDmax ST low-voltage switchgear**, Derun Electric leverages over a decade of experience in R&D and manufacturing of high- and low-voltage complete switchgear assemblies to provide end-to-end services—from solution design and equipment manufacturing to installation and commissioning. This article provides a comprehensive overview of the core advantages and key selection considerations for the MDmax ST.

## I. Product Overview

The MDmax ST is a new-generation modular low-voltage distribution cabinet manufactured under ABB authorization. It is a combined multifunctional low-voltage switchgear that has undergone **complete type testing (TTA)** and strictly complies with **GB/T 7251.12** and **IEC 61439** series standards. Built upon the foundation of the ABB ArTu low-voltage switchgear, this model represents a comprehensive upgrade that incorporates the advantages of similar products, featuring a **compact structure, flexible configuration, and proven reliability**.

The MDmax ST is widely applicable to power supply, distribution, and control systems across both building and industrial sectors, including **telecommunications, hospitals, municipal facilities, commercial buildings, high-end residential projects**, as well as **automotive manufacturing, steel and metallurgy, petrochemicals, electronics, food and pharmaceuticals, tobacco, and alcoholic beverage industries**.

## II. Key Technical Parameters

The following table summarizes the key technical parameters of the MDmax ST low-voltage switchgear, sourced from ABB official documentation and Anhui Derun Electric:

| Parameter Category | Specification | Value / Range |
| :--- | :--- | :--- |
| **Electrical Characteristics** | Rated Operational Voltage (Ue) | 400V / 690V AC |
| | Rated Insulation Voltage (Ui) | 690V / 1000V AC |
| | Rated Impulse Withstand Voltage (Uimp) | 6kV / 8kV / 12kV |
| | Rated Frequency | 50Hz / 60Hz |
| **Busbar System** | Main Busbar Rated Current (Ie) | Up to **6300A** |
| | Main Busbar Short-time Withstand Current (Icw) | Up to **100kA** |
| | Vertical Busbar Rated Current (Ie) | Up to **2000A** |
| | Vertical Busbar Short-time Withstand Current (Icw) | Up to **80kA** |
| **Structure & Environment** | Degree of Protection (IP Code) | Up to **IP54** |
| | Form of Internal Separation | Up to **Form 4b** |
| | Ambient Temperature | Max +40°C, 24h average ≤ +35°C, Min -5°C |
| | Maximum Installation Altitude | 2000m (derating required for higher altitudes) |
| **Dimensions & Enclosure** | Standard Cabinet Height | 2200 mm |
| | Standard Cabinet Width | 400 / 600 / 800 / 1000 / 1200 mm |
| | Standard Cabinet Depth | 600 / 800 / 1000 / 1200 mm |
| | Frame Material | Aluminum-zinc-coated steel sheet with double-folded edge technology |
| **Functional Units** | Main Structural Types | Drawer-type, detachable, plug-in |
| | Maximum Number of Circuits | Up to **36** drawer compartments per single cabinet |

> *Note: Technical parameters may vary by configuration. Please refer to the latest official documentation or technical agreement for final specifications.*

## III. Core Product Advantages

### 1. Sophisticated Design, Easy Installation

The MDmax ST adopts a **modular design**, allowing flexible configuration of incoming, feeder, reactive power compensation (MCC), soft-start, and other functional units. The cabinet frame features **25mm-spaced modular holes**, enabling convenient assembly while maintaining exceptional structural strength. The entire frame is precisely connected by horizontal and vertical bolts and is maintenance-free. The flexible and versatile design adapts to various application scenarios, while higher per-cabinet installation capacity helps optimize the number of cabinets and reduce footprint.

### 2. Full-Service Application, Benchmark Safety

The cabinet features a **self-supporting frame structure** constructed from double-folded G-section profiles. It is divided into four independent compartments—**busbar compartment, functional unit compartment, cable compartment, and auxiliary control compartment**—ensuring enhanced safety. Multiple mechanical interlocks prevent misoperation. The three-position drawer mechanism maintains its protection rating throughout all operating positions, making it suitable for harsh environments. Comprehensive drawer-type electrical operation solutions are available for remote control applications, and arc monitoring systems can be integrated for additional safety.

### 3. Advanced Technology, Smart and Efficient

The MDmax ST integrates multiple cutting-edge technologies:
- **Wireless radio-frequency temperature measurement** for safe and precise thermal monitoring;
- **Drawer health status monitoring** enabling predictive maintenance;
- **Stepless compensation technology** that perfectly matches load fluctuations without risk of over- or under-compensation;
- **ABB Ability™ EDCS (Electrical Distribution Control System)** for full life-cycle management of the power distribution system.

### 4. Robust Structure, Convenient Maintenance

The **removable top cover** of the horizontal busbar compartment facilitates on-site installation and busbar maintenance. Drawer units feature effortless operation with clear **audible, visual, and textual** three-state indicators. The product has passed stringent certifications including **IK9 seismic testing, internal arc, salt spray, and high-altitude** tests, making it suitable for applications with exceptionally high reliability requirements.

## IV. Standards and Compliance

The MDmax ST strictly adheres to **complete type testing (TTA)** requirements, ensuring reliable electrical performance. It complies with **GB/T 7251.12-2013** and **IEC 61439-1/2** standards, enabling broad application in both Chinese and international markets.

## V. Why Choose Derun Electric?

As an **ABB Gold Partner and authorized manufacturer of MDmax ST low-voltage switchgear**, Derun Electric offers three layers of assurance:

- **Authorized Quality**: Products strictly follow ABB technical standards and quality systems, ensuring that every switchgear cabinet meets original equipment quality requirements.
- **Professional Service**: Comprehensive services covering R&D, design, sales, manufacturing, installation, commissioning, and after-sales support.
- **Innovation Strength**: The company holds **99 patents** and multiple software copyrights, continuously driving product technology upgrades.

Derun Electric's products have been widely deployed across power plants, petrochemicals, textiles, high-rise buildings, and other industries, and exported to **more than fifty countries** including Brazil, Yemen, Ethiopia, and Indonesia. With proven capabilities and strong ABB partnership credentials, Derun Electric has become a designated supplier for numerous major national projects.

## VI. Selection and Ordering

For detailed technical documentation, solution configuration, or custom quotations for the MDmax ST, please contact the Derun Electric professional technical team:

- **Hotline**: 400-1287-988
- **Fax**: 0551-63645028
- **Email**: 3176885416@qq.com
- **Address**: No. 2, Shenlong Road, Gangji Town, Changfeng County, Hefei City, Anhui Province, China

Our team will provide customized technical solutions and full-service support based on your specific project requirements.