HXGN-12 box-type fixed metal-enclosed ring main unit switchgear

Q: Where are box‑type RMUs commonly used?

They are widely used in urban distribution networks, industrial facilities, substations, residential communities, commercial buildings, and prefabricated substation installations where reliable medium‑voltage distribution and sectionalization are required.

Q: What functions does an RMU provide in a distribution network?

An RMU enables safe circuit switching, fault isolation, load connection/reconnection and protection coordination, helping maintain continuous power supply even when part of the network is under maintenance or faulted.

Q: What types of switching devices can be used in RMUs?

RMUs can be equipped with load break switches, vacuum load break switches, fusion combinations or circuit breakers , depending on configuration and protection requirements.

Q: Why choose a metal‑enclosed design?

Metal‑enclosed switchgear offers enhanced safety, protection against foreign object entry, mechanical strength, and compartmentalization , reducing the risk of internal faults and improving maintenance access.

Q: What safety and interlock features are typical in an RMU?

Typical safety features include interlocking mechanisms between switches and doors, earthing switch interlocks, and mechanical safeguards that prevent unsafe operations or misoperations.

Q: Can RMUs be customized for specific distribution projects?

Yes. RMUs can be configured with various switchgear arrangements, protection devices, bus layouts, control schemes and automation options based on system requirements, fault levels and network topology.

The HXGN-12 box-type fixed metal-enclosed ring main unit switchgear is a ring main unit independently designed and developed by Zoliov, incorporating advanced technology. It has undergone type testing and long-term operational assessment, meeting the performance indicators of IEC298 and GB3906 standards, and features reliable operational protection with an IP3X protection level. The HXGN-12 is suitable for three-phase AC systems at 50Hz/60Hz,.6KV, 10KV, 11KV, especially in distribution systems for factories, workshops, and high-rise residential buildings.

Key Features:

Compact Design: The cabinet body is constructed using 8MF steel, making it lightweight and easy to install and maintain.

Sturdy Structure: The cabinet features an assembly-type structure, providing high stability and flexible extension options.

Safety Performance: The load switch is equipped with an insulated cover for the static contact, effectively preventing arc short circuit accidents within the cabinet, ensuring safe operation.

Automatic Isolation: The load switch has a unique metal door and grounding structure that automatically closes upon tripping, ensuring that the switchgear room is isolated from the energized busbar compartment, enhancing safety.

Why choose the HXGN15-12 type box-type fixed metal enclosed ring main unit switchgear equipment

he HXGN-12 box-type fixed metal-enclosed ring main unit switchgear is designed for use in ring main unit systems, serving as an equipment for receiving, distributing, and protecting electrical energy. It supports dual current radial supply systems and meets the needs of urban power grid renovations and construction. Depending on user requirements, this device can be equipped with vacuum and air-insulated load switches and combined electrical appliances, offering both manual and electric operation options for easy load control and maintenance. Its modular design allows users to flexibly adjust configurations based on actual needs.

Product Advantages

Simple and Reliable Structure: The cabinet offers a straightforward and dependable design with economical cost and excellent value for money.

Compact Size: Its compact structure saves installation space and makes both installation and maintenance more convenient.

Stable Protection Performance: The combination of load switch and fuse provides stable and effective protection performance.

Complete Interlocking System: The cabinet is designed with reliable interlocking for safe operation and strong prevention of misoperation.

Wide Environmental Adaptability: It performs reliably in humid and dusty environments with stable long-term operation.

Flexible Modular Configuration: The modular design can flexibly support incoming and outgoing lines, PT units, and other distribution schemes.

Operating Conditions

Environmental Temperature: Not exceeding +40℃ and not lower than -15℃, with an average temperature not exceeding +35℃ within a 24-hour period.

Humidity Requirements: Clean air, with relative humidity not exceeding 50% at a maximum temperature of +40℃, and allowing higher humidity at lower temperatures.

Altitude: Not exceeding 1000 meters.

Air Quality: The surrounding air is free from significant pollution by dust, smoke, corrosive and/or flammable gases, vapors, or salt mist.

Application

The HXGN-12 is mainly used in residential areas, factories, municipal infrastructure, small substations, and other applications, serving as ring network power supply, terminal distribution, and transformer protection equipment for medium-voltage power systems.

Model meaning

Technical Parameters

Overall and mounting dimensions(mm)（Reference）

Model meaning

HXGN-12 Box-Type Fixed Metal-Enclosed Ring Main Unit Switchgear	H:	Ring main unit
	X:	Box-type structure
	G:	Fixed installation
	N:	Indoor type
	12:	Rated voltage 12kV

Technical Parameters

Item	Specification
Rated Voltage	12 kV
Rated Frequency	50 Hz
Rated Current	630 A (standard), optional 400 A / 1250 A
Rated Short-Time Withstand Current	20 kA / 25 kA / 31.5 kA (1 s)
Rated Peak Withstand Current	50 kA / 63 kA / 80 kA
Power Frequency Withstand Voltage	Phase-to-phase / phase-to-earth: 42 kV (1 min)
Lightning Impulse Withstand Voltage	Phase-to-phase / phase-to-earth: 75 kV
Insulation Type	Air insulation
Degree of Protection	IP3X (with enclosure door closed)
Mechanical Endurance	Load switch ≥ 10,000 operations
Ambient Temperature	-25°C to +40°C
Installation Altitude	≤ 1000 m (customizable up to 2000 m)
Applicable Standards	GB/T 3906, GB/T 11022

Overall and mounting dimensions(mm)（Reference）

HXGN-12 Dimension Drawing

FAQ

What is a ring main unit (RMU)?

A ring main unit (RMU) is a factory‑assembled, metal‑enclosed set of medium‑voltage switchgear used in power distribution networks to control, protect and distribute electrical power, often in a ring or loop configuration to improve supply reliability.

What does “fixed box‑type metal‑enclosed” mean for an RMU?

“Fixed box‑type metal‑enclosed” refers to a switchgear design where the RMU is integrated into a rigid metal enclosure with a box structure, typically installed indoors or in prefabricated substations and not designed to be easily pulled out like withdrawable cabinets.

Where are box‑type RMUs commonly used?

They are widely used in urban distribution networks, industrial facilities, substations, residential communities, commercial buildings, and prefabricated substation installations where reliable medium‑voltage distribution and sectionalization are required.

What voltage levels do these ring main units support?

Box-type RMUs are commonly designed for medium-voltage systems with voltage ratings up to 35 kV, and are also available in 11 kV, 7.2 kV, and other medium-voltage ratings to match different distribution network requirements.

What functions does an RMU provide in a distribution network?

An RMU enables safe circuit switching, fault isolation, load connection/reconnection and protection coordination, helping maintain continuous power supply even when part of the network is under maintenance or faulted.

What types of switching devices can be used in RMUs?

RMUs can be equipped with load break switches, vacuum load break switches, fusion combinations or circuit breakers, depending on configuration and protection requirements.

Why choose a metal‑enclosed design?

Metal‑enclosed switchgear offers enhanced safety, protection against foreign object entry, mechanical strength, and compartmentalization, reducing the risk of internal faults and improving maintenance access.

What safety and interlock features are typical in an RMU?

Typical safety features include interlocking mechanisms between switches and doors, earthing switch interlocks, and mechanical safeguards that prevent unsafe operations or misoperations.

What environmental conditions should be considered when installing RMU equipment?

Standard indoor or prefabricated substation installations consider ambient temperatures, altitude limits, humidity, and absence of corrosive or explosive gases. Project‑specific conditions may require customized designs.

Can RMUs be customized for specific distribution projects?

Yes. RMUs can be configured with various switchgear arrangements, protection devices, bus layouts, control schemes and automation options based on system requirements, fault levels and network topology.

Related products

Check out these related products you might also be interested in.

GTXGN-12 Solid Insulated Ring Main Unit

Ring Main Unit GTXGN-12 Solid Insulated Ring Main Unit The GTXGN-12 Solid Insulated Ring Main Unit (RMU) is an innovative, environmentally friendly, and fully sealed

Medium-voltage electrical components

Electrical components Medium-voltage electrical components Medium voltage electrical components are essential in power systems, designed to handle and transmit medium voltage efficiently. They ensure the

Low-voltage electrical components

Electrical components Low-voltage electrical components Low-voltage electrical components are essential devices used in circuits with voltages below 1200V (AC) or 1500V (DC). These include circuit

Electric Power Fittings

Zoliov provides electric power fittings, power line fittings, overhead line fittings, and pole line hardware for transmission lines, distribution lines, substations, and power grid projects.

The application of electrical equipment in data centers

You need electrical equipment to help data centers work well. Good systems stop outages, which can cost a lot of money. Power problems are the

The application of electrical equipment in the charging infrastructure of electric vehicles

You will see many important types of electrical equipment in electric vehicle charging stations, which are a crucial part of the charging infrastructure. These include

The Key Role and Solutions of Electrical Equipment in New Energy Projects

Electrical equipment plays a key role in ensuring that new energy projects operate effectively. Electrical engineers and electricians are essential in maintaining the safety and

Efficient power distribution: A comprehensive selection from low-voltage distribution cabinets to high-voltage switchgear

You have an important job when you pick the Efficient switchgear for your building, especially considering the role of power distribution. The world market for

Get in Touch

Have questions or concerns about electrical power distribution products? Get answers quickly by emailing our engineers.

Nearly 20 Years of Industry Experience

10,000⁺ Units/Year Production Capacity

40,000^m²+ Factory Area

500⁺ Power Utility Clients

1 Billion⁺ CNY Annual Sales Revenue