Eaton HMH Series Medium Voltage Switchgear

Eaton HMH Series Medium Voltage Switchgear
Image Source: Eaton

Eaton HMH series metal-enclosed modular switchgear are medium voltage assemblies for use in secondary distribution systems, compact kiosk-type transformer substations, and industrial facilities. They are designed for indoor/ outdoor use. All functional units can be installed easily side by side. The switchgear is factory assembled and undergoes all routine type-approval tests. Units can be commissioned quickly and safely.

HMH Series medium voltage switchgear is designed for secondary distribution systems up to 36 KV, compact kiosk type transformer substations, and industrial facilities and indoor spaces. All functional units can be easily installed side by side. The metal-enclosed switchgear is produced in the factory with all routine and type tests conducted and can be commissioned in a brief period–practically and safely. Moreover, HMH Series modular switchgear can be quickly and safely used in kiosk type transformer substations due to their compact and minimized dimension.


HMH switchgear is divided into three compartments, i.e.,

  • Busbar Compartment
  • Cable Connection and Switching Compartment
  • LV Compartment
Compartments of HMH Switchgear | Image Source: Eaton
  • (1) Busbar Compartment: The main busbar is in this compartment and is where the primary busbar connection is made. Busbars can be aluminium or copper. The breaker varies depending on the rated current value.
  • (2) Cable connection and Switching Compartment: Medium voltage cable connections are in this compartment. The earthing switch, breaker, support insulator, capacitive insulator, current transformer, voltage transformer, MV fuse and earthing busbar are also located in this compartment.

(3) LV Compartment: Terminal blocks, LV fuses, thermostat, measuring instruments and protection relays are in this compartment. When the switchgear (busbars and cables) is energized, the operation is possible via the LV panel.

Image Source: Eaton


Eaton’s HMH Series RMU is air-insulated medium voltage switchgear available from 12 KV to 36 KV. According to IEC standards, it is well designed & factory-assembled, type-tested switchgear up to 36 KV, 1250 A, 25 KA. It has a modular structure in consideration of functionality, appearance, and security features. HMH Series delivers safe operation with mechanical and electrical interlocks. It also has a long-life cycle and low power consumption. It works on a motorized or manual operated spring-charged mechanism.

Eaton’s HMH switchgear offers 50% space-saving on footprint compared to other available solutions in the market.

Image Source: Eaton


Value ranges

• Up to 36 kV, 1250 A, 25 kA

• 12 / 24 / 36 kV

• Compliant with IEC standards

• Customized types


• Equipped with safety locks

• Internal arc classification IAC AFL

• Classified LSC-2A, PI

• Fixed-type circuit breaker


Wide variety of applications

• 24 kV vacuum circuit breaker and 36 kV SF6/Vacuum circuit breaker

• Load break switch (LBS)

• Manual disconnector

• Block voltage transformer, block/ toroidal current transformer

• Wall-mounted or free-standing


• 100% Eaton quality, factory tested

• Extensive installation network

• Installed in countries worldwide

• Approved for use in special environments including maritime, earthquake and nuclear; type tested in line with IEC standards


• Protection and control

• Earthing switch


  • Modular Switchgear: HMH Series Modular Switchgears are easy to operate with their basic interlocking systems. The door, Load Break Switch and Earthing Switch are connected using the interlocking system, which provides safety for the operation staff.
  • Metal Enclosed Switchgear: HMH Series Switchgears are designed with a modular structure considering functionality, appearance, and security features. Switchgear carcasses are manufactured of 2 mm hot-dip galvanized sheet metal, with a thickness of 275gr/m² galvanize, which is above the industry standards; it is not subject to any deformation even under the dampest mediums.

Suppose you want complete protection against electrical hazards. In that case, you should have selected the right product which offers protection from essential to advance security & Eaton’s HMH Switchgear ensure the continuity of the system with utmost safety and protection.”


Eaton’s mission is to improve the quality of life and the environment using power management technologies and services. We provide sustainable solutions that help our customers effectively manage electrical, hydraulic, and mechanical power – more safely, more efficiently, and more reliably. Eaton’s 2020 revenues were $17.9 billion, and we sell products to customers in more than 175 countries. We have approximately 85,000 employees.


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