Until now, circuit-breakers have relied on the electrical arc generated by the separation of
metallic contacts to interrupt both normal and fault currents. This principle, introduced
over a century ago, has remained the foundation of conventional circuit-breaker
technology.
Transistors such as MOSFETs* or IGBTs** have been widely used for decades in
electronic devices. When designed to conduct and interrupt high current levels, ranging
from a few amperes to several thousand amperes, they are referred to as power
semiconductors.
Recent progress in these components now enables us to consider circuit-breakers based
on semiconductors to break the current. This technology can provide significantly
improved performance:
- Very small breaking durations (down to a few microseconds compared to milliseconds
for traditional circuit-breakers) - Very high number of load switching operations
- “clean” breaking with negligible gas exhaust
Several circuit-breaker manufacturers have recently introduced devices based on
semiconductor technology, highlighting the urgent need for a dedicated product standard
to define minimum safety and performance requirements. This standard, titled IEC 60947
10, has been published in May 2026.
A technology enabling the energy transition and the new energy landscape
This technology offers great electrical performance and advanced functionalities, making
it a key enabler for the energy transition and the evolving energy landscape:
- Enhanced short-circuit performance, with high current-limiting capabilities,
particularly valuable in demanding applications such as data centers. - Seamless load management in microgrids, thanks to native remote control.
- Improved selectivity in direct current (DC) systems, enabling new system
architectures. - Integrated smart functionalities, including protection, remote control, metering, and communication, paving the way for miniaturization and simplified digital integration.
This technology can be implemented through two main types of architectures:
- Pure Semiconductor Circuit-Breakers (SCCBs): in this configuration, the normal current continuously flows through power electronic components. These devices offer extremely fast interruption times (typically within tens of microseconds) but tend to generate significant power losses during normal operation.
- Hybrid Semiconductor Circuit-Breakers (SCHCBs): here, the rated current flows
through traditional metallic contacts under normal conditions, while interruption is
handled by power semiconductors. Although slightly slower than SCCBs (interruption within hundreds of microseconds), this architecture achieves much lower power losses, comparable to those of conventional circuit-breakers.
The key requirements concerning these circuit-breakers
The IEC 60947-10 standard defines essential requirements to ensure the same level of
safety as electromechanical circuit-breakers, along with clear transparency regarding
device performance:
- Safety through isolation: Devices will incorporate isolating contacts to guarantee
suitability for isolation, ensuring the safety of electricians during maintenance
operations. - Remote control capabilities: These circuit-breakers may feature a standby position,
where isolating contacts remain closed while the power semiconductor is in a high
impedance state. This configuration enables valuable remote control functionalities.
The standard specifies minimum requirements for this mode, particularly regarding
leakage current and state indication. - Control power supply management: Control circuits will typically be powered either
by the line voltage or an external source. The standard includes tests to verify
acceptable voltage ranges and defines rules for managing the circuit-breaker’s state in the event of power loss. - Electronic component reliability: Specific provisions are included to assess the
reliability of electronic components and to evaluate the impact of potential failures. - Comprehensive type testing: Six type test sequences are defined to validate the
correct operation of these circuit-breakers across a range of application scenarios.
Other standards
UL has published in October 2025 a dedicated product standard for semiconductor
circuit-breakers, known as UL489I. This standard builds upon the principles of UL489 and
incorporates requirements similar to those defined in IEC 60947-10.
China also issued a group standard in 2024, designated T/CEEIA 782-2024, based on the
existing draft of IEC 60947-10 at that time. The publication of a GB/T standard based on
IEC 60947-10 is scheduled for 2028.
When will Schneider Electric provide such circuit-breakers?
Schneider Electric is actively investing in this technology and exploring various options,
carefully balancing application electrical requirements with constraints such as device
footprint, power losses, and product cost. Semiconductor circuit-breakers have already
been released in accordance with GB standard.
Summary
A new standard dedicated to semiconductor circuit-breakers, IEC 60947-10, has been
released to define the minimum safety and performance requirements for these innovative devices, which will be key enablers of the evolving energy landscape and emerging applications.
(*) Metal-Oxide-Semiconductor Field-Effect Transistor
(**) Insulated Gate Bipolar Transistor
About the author
Hervé Anglade, Circuit-Breaker Architect
I have specialized since 2003 in power low voltage electrical devices in Schneider Electric (architecture, design, quality, standardization). Since February 2023, I am a circuit-breaker architect in Home & Distribution.
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