Accelerate grid digitisation with smart RMUs
Modernise your grid with the smart ring main unit (RMU)
The ring main unit is a compact, fully enclosed, factory-built cabinet designed for medium voltage (MV) power distribution. This switchgear unit is straightforward to replace, requires minimal maintenance, and offers high levels of protection. To cater to varied needs, RMUs come in different voltage options, making them suitable for both outdoor and indoor applications. At Schneider Electric, we bring advanced technology and innovation to your grid through our exclusive range of smart ring main units, ensuring safety and efficiency in upgrades.
Seamlessly integrated with the PowerLogic T300 remote terminal unit (RTU) and our innovative conditional monitoring sensors, the smart RMU is an innovative solution that makes it easier for you to answer the evolving challenges of electrical distribution. As an all-in-one solution, the smart RMU is easy to purchase, install and maintain, helping to reduce operational costs. Its robust design fits even the harshest environments.
A smart RMU is an advanced version of the traditional Ring Main Unit, designed for MV distribution networks. While a conventional RMU provides basic switching and protection functions, a smart RMU integrates digital technologies such as advanced analytics, remote monitoring, automated fault detection, and grid reconfiguration. It is typically equipped with sensors, communication modules, and remote terminal units (RTUs), enabling real-time data acquisition and integration with smart grid platforms.
Smart RMUs offer a range of digital functionalities, including:
• Remote control and monitoring via SCADA systems and RTUs like PowerLogic T300.
• Condition monitoring using thermal sensors, partial discharge sensors, and predictive analytics.
• Cybersecurity compliance with standards such as IEC 62351 and IEEE P1686.
• Automated fault isolation and power restoration, reducing outage times and improving SAIDI metrics.
• Integration with distributed energy resources (DERs) and support for grid decarbonisation and decentralisation.
Smart RMUs bring several advantages:
- Enhanced reliability through looped network configurations and advanced monitoring, protection, control and automation functions thanks to RTU usage.
- Reduced operational and maintenance costs due to predictive maintenance and fewer manual interventions.
- Improved energy efficiency and load management via advanced analytics available in RTU.
- Environmental sustainability, especially with SF6-free usage.
- Improve energy availability with a cost- and time-effective solution (SAIDI).
RM6
Learn more about our 2,000,000+ modules with installed MV ring main unit.
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FBX
Discover flexible installation in compact or extensible applications.
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Ringmaster
Find out more about our MV ring main units for outdoor applications.
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PowerLogic T300
Discover a powerful Remote Terminal Unit (RTU) for feeder automation.
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Discover how digitisation, decarbonisation, and decentralisation are transforming the energy world.
Condition monitoring of ring main units (RMU)
Find out how an effective asset management and capital improvement program aims to pinpoint the exact location of the distribution network needing maintenance and repair, without the guesswork.
Why choose smart RMU
Faster power restoration thanks to decentralised schemes
Compliance with the latest cybersecurity standards
Expertise of the RMU market leader with +2.5 M installations worldwide
Smart RMU Connected Enabled
Our entry-level offer will help you improve everyday equipment maintenance and reduce OpEx costs. It features wireless thermal sensors and a smartphone app to replace infra-red thermal scanning. It also enables early detection of conditions that can result in electrical connection failures, fires, arc flashes, or worse.
Smart RMU Connected Advanced
Discover our fully-optimised and integrated, advanced-level offer for controlling, metering, condition monitoring, and fault detection. Reduce operation and maintenance expenditures, and optimise your networks for increased demand. This advanced solution is available for RM6, FBX and Ringmaster.
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What does a ring main unit do?
An RMU (Ring Main Unit) is a compact, enclosed switchgear device that distributes, controls, and protects medium-voltage electrical networks, ensuring reliable power supply, rapid fault isolation, and improved grid efficiency in a wide range of industrial and utility settings.
Key features and functions of an RMU
An RMU provides essential functions for electrical distribution: circuit control, fault isolation, and network protection. It comprises switches, circuit breakers, and fuses to manage load switching, safeguard transformers, and minimize outage risks. Compact and robust by design, RMUs ensure continuous supply, quick restoration during faults, and compliance with international safety standards. These units help utilities reduce operational costs and improve reliability while supporting efficient asset and network management in both secondary and distribution grids.
Applications of an RMU
Ring main units are widely used in urban and industrial power networks to enable stable electricity distribution and efficient load management. RMUs supply power in residential complexes, commercial buildings, hospitals, ports, and substations, as well as renewable energy sites like wind and solar power plants. Their ability to quickly isolate faults and reroute power makes them ideal for environments where uninterrupted energy is critical, ensuring operational safety and reliability across compact secondary substations and dense metropolitan infrastructure.