Compact, factory-assembled RMU cabinets for safe and reliable MV/HV distribution between 7.2 kV – 36 kV. Designed for indoor and outdoor use with integrated transformer protection, fault isolation, and easy expansion.
A Ring Main Unit (RMU) cabinet, also known as a medium voltage cabinet, is an integrated piece of electrical equipment designed to connect, measure, protect, and control medium voltage power distribution. It brings together fixed-type breakers and transformer protection in a compact, factory-assembled enclosure, improving the reliability and safety of your network.
RMU cabinets are engineered to enhance the performance of power distribution networks while offering advanced protection for transformers and other critical electrical assets. With modular construction and configurable busbar sections, RMUs are simple to install, maintain, replace, and expand as your system grows. They are available in both indoor and outdoor configurations, making them ideal for industrial, commercial, and utility applications.
ACB-based Ring Main Units use Air Circuit Breakers for protection and control of medium voltage feeders and transformers. They provide reliable protection against overcurrent, short circuits, and earth faults, and are well suited for industrial and commercial installations with higher current ratings.
VCB-based RMUs extinguish the arc inside a sealed vacuum interrupter, delivering fast fault clearance, high reliability, and minimal maintenance. They are commonly deployed in urban and underground distribution networks where space is limited and uptime is critical.
SF6 RMUs use sulfur hexafluoride gas as the interrupting medium, offering high dielectric strength, compact footprint, and excellent arc-quenching capabilities. Ideal for medium-voltage networks, especially where high fault levels need to be handled in confined spaces.
LBS-type RMUs are equipped with load break switches instead of full circuit breakers. They are designed to switch and isolate circuits under normal load conditions and are a cost-effective option for rural or lower-demand distribution networks where fault levels are relatively low.
Combined RMUs integrate more than one type of interrupter technology (ACB, VCB, SF6) within a single assembly. This provides flexible protection strategies and allows different feeders or transformers to be protected according to their duty and criticality.
Our RMUs include key components such as load break switches, circuit breakers, fault passage indicators, power supply units, current and potential transformers, HRC fuses, and solid-insulated busbars. We also supply matching cables and termination kits for complete project packages.
We supply fully assembled, enclosed Ring Main Units for MV/HV power distribution across the Pacific region, with voltage ranges between 7.2 kV and 36 kV. Our experience includes industrial, commercial, and utility customers requiring compact secondary substations, transformer protection, and multiple input feeders.
Ring Main Units (RMU) – Medium Voltage Distribution Solutions
iEngineering supplies fully assembled Ring Main Units (RMUs) for medium voltage power systems in the 7.2 kV – 36 kV range. These cabinets are designed as compact, integrated substations that connect, protect, and measure your distribution network, with both indoor and outdoor variants available.
RMUs are ideal for compact secondary substations, transformer protection, and networks that require multiple input feeders to minimise outages and improve continuity of supply.
RMU cabinets are fully enclosed, factory-assembled metal-enclosed switchgear. They integrate switching, protection, and measurement in a compact footprint while providing clear segregation of live parts and safe operator access.
Our RMUs are suitable for medium voltage networks within a typical voltage range of 7.2 kV – 36 kV, serving a broad spectrum of applications:
RMUs incorporate different interrupter technologies (ACB, VCB, SF6, LBS) to protect transformers and feeders while allowing safe switching and isolation.
Each RMU can be equipped with a combination of components depending on your project needs:
RMUs are available in both indoor and outdoor enclosure designs, allowing a consistent solution from substations to field distribution points.
RMUs are designed as low-maintenance, long-life assets that improve network reliability and reduce operating costs.
In addition to RMU supply, we offer associated medium voltage cables, termination kits, and project engineering support to deliver a complete solution for your site.
Get a free, no-obligation quote from our experts. Whether it’s RMUs, LV panels, installations, repairs, or upgrades, we provide reliable and efficient solutions.
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At iEngineering, we provide reliable medium voltage RMU solutions through a complete end-to-end process. We start by understanding your network configuration and site requirements, then prepare detailed designs, SLDs, and technical specifications to meet utility and project standards. Each RMU is manufactured and tested before dispatch, with on-site support for installation, SAT, and commissioning to ensure safe operation and seamless integration with your electrical system.
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We review your project, SLD, and site needs to propose the most suitable and cost-effective RMU configuration for your network.
Detailed design, GA drawings, and technical documentation are prepared. RMUs are then manufactured using certified components to meet the relevant MV standards and utility requirements.
Each RMU undergoes FAT, including wiring checks, insulation resistance, interlock operation, and functional testing. Clients may attend online or in person.
Safe, on-time delivery of RMUs across Australia and the Pacific, complete with documentation, test reports, and lifting/handling instructions.
We provide guidance or supervision for RMU installation, ensuring that cable terminations, earthing, and clearances comply with drawings and safety standards.
On-site checks for wiring, insulation, interlocks, and operation, with final adjustments as needed prior to energisation.
Final energisation, protection testing, and system integration ensure your RMUs are fully operational and delivering reliable power distribution.
Past Project Experience
2024
Location : Solomon Island
2022
Location : Solomon Island
2020
Location : NSW Australia
2020
Location : NSW Australia
2019
Location : Honiara, Solomon Islands
Skilled professionals delivering safe and efficient electrical solutions.
We complete projects promptly with guaranteed quality.
Ensuring the highest safety standards in every job.
Honest, upfront pricing with no hidden fees.
Need reliable RMU or electrical solutions? Contact us today for expert service!
About us
iEngineering is your trusted partner for advanced electrical and energy solutions across Australia, Fiji, and India. We deliver high-quality hardware products from switchboards and transformers to solar, BESS, RMU, and EV charging systems backed by expert engineering, reliable installation, and dedicated local support.
At iEngineering Australia, our mission is to enhance efficiency, ensure quality control, and deliver customer satisfaction through innovative engineering solutions. We are committed to global standards and sustainable solutions that create long-term value for our clients and communities.
Our vision is to be a global leader in engineering solutions, driving industry leadership, innovation, and customer-centric growth. We aim to inspire through global influence, foster expansion and growth, and play an inspirational role in shaping the future of engineering.
Our values guide everything we do: integrity & ethics, a strong commitment to quality, and diversity & inclusion. Safety, reliability, and continuous improvement are the cornerstones of our success, enabling us to deliver trusted and innovative solutions worldwide.
Our Journey
Founded in 2013, iEngineering Australia delivers a comprehensive range of high-quality electrical and energy hardware solutions tailored for Australian and Pacific conditions. From design and engineering to manufacturing, testing, and commissioning support, we ensure every product—whether switchboards, RMUs, transformers, solar systems, or EV chargers—is safe, reliable, and built to last.
Where We Operate
iEngineering Australia operates across Australia, Fiji, and India, delivering reliable technology and asset management solutions to organisations of all sizes—from local enterprises to large multinational companies.
Phone: +61 (02) 8318 1490
Email: dnaiker@iengaust.com.au
Warawara Cct, Quakers Hill NSW 2763, Australia
View mapPhone: +91 9168627258
Email: shila@iengaust.com.au
Navale IT Zone, Office No. 501, 5th Floor, A-Wing, Near Navale Bridge, Mumbai-Bangalore Highway, Narhe, Pune – 411041.
View mapPhone: +679 9488589
Email: dnaiker@iengaust.com.au
Lot 17, River Drive, Pacific Harbour, Navua, Suva, Fiji.
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