By Matthieu Guillot (Electrical Distribution Technical Expert) & Siming Ma (EcoStruxure Power Partner Director)

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Circuit breakers help ensure the safety and reliability of electrical distribution systems in all facility types. Low-voltage (LV) circuit breakers need checking to ensure proper configuration to operate as expected during their entire lifecycle. This validation is the combined responsibility of specifiers, panel builders, installers, and service technicians. This article explains why, when, how, and by whom should perform testing and how the newest software makes it faster and easier to perform and share test reports.

Most of today’s circuit breakers designed for simple protection functions in final distribution applications are non-adjustable, so they do not require any unique configuration.

However, circuit breakers designed for LV applications above 100 A in main switchboards  typically integrate protection for many fault conditions, like overload, short circuit, and earth fault. Many of these breakers configure to coordinate protection between each other – using selectivity and cascading – to help minimise impacts of electrical faults while preserving supply continuity for the rest of a facility. Circuit breakers offering this level of protection and reliability have adjustable settings that need configuration.

During the design phase of a new facility, upgrade, or expansion, the latest advanced software design tools, such as ETAP or Caneco ONE, can specify settings for each circuit breaker in an electrical system based on various parameters, e.g., cable cross-section. To optimise safety and reliability, it is essential that the specified breaker settings during the design stage are applied to each circuit breaker and maintained to ensure optimised performance during electrical instillation’s operational lifecycle.

There are three important reasons to check circuit breakers to certify proper configuration and operation:

Though circuit breakers must be properly configured, it is unfortunately prevalent that large numbers of breakers do not have their optimised settings configured when buildings are designed, constructed, and operated. We estimate that at least one-third of adjustable circuit-breaker remain with factory settings. There can be many reasons for this:

If not configured, circuit breaker settings remain in their factory defaults. A circuit breaker with factory settings might still pass a building inspection, but there is the risk of:

Checking circuit breaker settings during the construction phase and periodically during the facility's operation will avoid these risks by ensuring conformity of the built installation with the calculations done during design. However, mandatory checking is usually performed visually. This poses a risk of human error with poor traceability.

Additionally, periodically testing circuit breakers is an essential preventative maintenance step to help find early indications of a potential operational issue. Circuit breakers may be inactive for months or years before a fault. This will give you time to fix the issue before it can cause a problem.

As per the standards noted above, checking LV circuit breaker settings should be executed multiple times over the circuit breaker's lifecycle. Here are some additional considerations:

Testing at the initial installation stage:

Periodic testing during facility operation:

EcoStruxure™ Power Commission ( formerly known as Ecoreach) is an intelligent digital testing tool compatible with all Schneider Electric circuit breakers with electronic trip units, power and energy meters, and communication gateways. EcoStruxure Power Commission is a software app that runs on a laptop computer. This mobility makes it ideal for circuit breaker initial validation testing before installation and periodic testing during facility operations.

EcoStruxure Power Commission automates setting, commissioning, and testing, making these steps safer, faster, and more reliable, with less human error. The newest version of this software is simplified to allow direct connection of the laptop to any Schneider Electric MasterPacT MCB or ComPacT MCCB circuit breaker with as little as a USB cable or Field Services Interface. It supports routine checkups, secondary injection testing, preparation for primary injection testing (if required in special cases), and zone selective interlocking testing.

Settings are automatically documented in a digital logbook to save time while enabling consistency and traceability. EcoStruxure Power Commission can also quickly and automatically generate a project report to share with all stakeholders to give them peace of mind that circuit breakers are correctly configured and performing safely and reliably. Save the report as part of the documentation associated with each circuit breaker.

In the future, we envision digital design tools like ETAP or Caneco BT software to offer seamless connectivity between the 'digital twin' and EcoStruxure Power Commission. This will enable direct upload of specified settings for each breaker in the electrical system for even greater time savings.

To learn more, download our e-guide: Faster circuit breaker testing while improving safety and uptime.

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