Why Choose the ABB CMS-121CA 40 A Open-Core Current Sensor?
The ABB CMS-121CA is a compact 40 A open-core current sensor designed for detailed branch-circuit measurement within ABB Circuit Monitoring System and InSite energy-management installations. Its 18 mm open-core construction and universal cable-tie mounting make it particularly useful for retrofit applications where disconnecting an existing conductor for sensor installation would be undesirable.
The CMS-121CA provides a 0.1–40 A measuring range and is designed for monitoring individual electrical circuits and loads. Its open-core design simplifies installation around an existing conductor, while accuracy class 1 supports reliable circuit-level measurement for energy analysis, load supervision and electrical-system monitoring.
Measurement information is transmitted through the ABB InSite bus using a flat cable to compatible monitoring equipment. With universal cable mounting, compact dimensions and an operating temperature range of -25 to +70 °C, the CMS-121CA provides a flexible solution for new and retrofit energy-monitoring installations in commercial, industrial and critical-power distribution systems.
Key Advantages
- Compact 40 A open-core current sensor for individual circuit monitoring.
- 0.1–40 A measuring range for branch and final circuits.
- Open-core construction simplifies installation around existing conductors.
- 18 mm sensor format supports compact distribution-board installations.
- Universal cable-tie mounting provides flexible positioning around the monitored conductor.
- Accuracy class 1 for dependable circuit-level monitoring.
- InSite bus connectivity enables integration into ABB monitoring systems.
- Well suited to retrofit projects where existing wiring should remain connected during sensor installation.
Key Features
- ABB CMS Circuit Monitoring System.
- 40 A current sensor.
- 18 mm open-core construction.
- 0.1–40 A measuring range.
- Accuracy class 1.
- Universal cable-tie mounting.
- InSite bus communication via flat cable.
- Designed for circuit-level current and energy monitoring.
- Open-core architecture supports straightforward retrofit installation.
- Compact construction for densely populated distribution boards.
- Suitable for commercial, industrial and critical-power applications.
- Operating temperature range from -25 to +70 °C.
Flexible Open-Core Circuit Monitoring
The ABB CMS-121CA is designed to simplify the addition of circuit-level monitoring to existing electrical installations. Unlike a solid-core sensor, its open-core design can be positioned around an existing conductor without first routing the conductor through a permanently closed sensor aperture. This makes the CMS-121CA especially useful when upgrading operational distribution boards with detailed energy and load monitoring.
The 0.1–40 A measuring range enables individual branch and final circuits to be monitored, providing more granular information than measurement at the main incoming supply alone. When integrated into a compatible ABB monitoring architecture, multiple CMS sensors can support energy-efficiency analysis, load supervision and improved visibility of electrical consumption throughout an installation.
Typical Applications
- Retrofit branch-circuit current monitoring.
- Commercial building energy-management systems.
- Industrial electrical distribution boards.
- ABB CMS and InSite monitoring systems.
- Individual electrical load monitoring.
- Energy-consumption analysis at circuit level.
- Existing distribution boards where conductor disconnection is undesirable.
- Data centres and critical-power infrastructure.
- Building automation and energy-efficiency projects.
- Distribution systems requiring universally mounted open-core sensors.
