In any three-phase electrical system from industrial plant floors to commercial building infrastructure unseen dangers can develop over time. Insulation degrades, environmental moisture seeps in, or accidental damage occurs. These events create ground faults: unintended electrical paths where current leaks to earth. Left undetected, they pose a severe risk of electric shock to personnel, potential for catastrophic electrical fires, and disruptive equipment damage.
Traditional circuit breakers often can’t catch these faults. They’re designed for overcurrent, not for sensing the small, imbalanced leakage currents that signify a ground fault. This is where dedicated protection is non-negotiable.
How the S2 ELR1 + CBCT System Works:
The system’s operation is elegant and highly effective, based on a fundamental principle of electrical balance.
1. Detection by the CBCT: The Core Balance Current Transformer is installed by passing all three phase conductors (and the neutral, if present) through its center. Under normal, healthy conditions, the sum of the currents flowing “to” and “from” a load is zero. Their magnetic fields cancel each other out, resulting in zero net flux in the CBCT core, and thus, no output signal.
2. Identifying the Fault: When a ground fault occurs, current finds an alternative path to earth. This creates an imbalance. The currents no longer sum to zero, and the resulting magnetic field is detected by the CBCT, which generates a proportional output signal to the relay.
3. Intelligent Response by the S2 ELR1 Relay: The microcontroller-based S2 ELR1 relay receives this signal. It compares the leakage current value against your pre-set, adjustable trip threshold. If the fault persists for the duration of the adjustable trip delay, the relay instantly activates its heavy-duty output contacts. These contacts can trip a circuit breaker, sound an alarm, or shut down a process, isolating the hazard.
Key Features & Technical Advantages:
- Microcontroller-Based & SMD Technology: This isn’t an old-fashioned electromechanical device. The use of a microcontroller and Surface Mount Device technology ensures high accuracy, stable performance, and resistance to environmental influences like vibration.
- Wide, Adjustable Sensitivity: With trip settings adjustable from a very sensitive 0.03A (30mA) up to 30A, the system can be finely tuned. Protect human life with high sensitivity in accessible areas (30mA range) or protect equipment and against fire risks with higher settings for machinery and feeders.
- Flexible Power & Installation: The relay accepts a vast range of auxiliary supply voltages (24VDC to 415VAC ±20%), making it compatible with virtually any control panel. The CBCT is available in multiple internal diameters (35mm to 150mm), allowing it to fit over cables and busbars easily—no need to break connections.
- Manual Reset & Test Function: After a trip, the manual reset ensures the fault condition is investigated and cleared before restarting, enforcing safe procedures. The integrated test push button allows for regular, functional safety checks to ensure the entire system is operational.
Robust Construction for Demanding - Environments: Rated to operate reliably in temperatures from -5°C to +60°C and up to 95% Relative Humidity, it is built for real-world industrial conditions.
Critical Applications Across Industries
The versatility of the S2 ELR1 system makes it a cornerstone of modern electrical protection:
- Manufacturing & Industrial Plants: Protecting motor feeders, machine tools, and production line electrical supplies from insulation failure.
- Commercial Buildings: Enhancing safety in main and sub-distribution boards, guarding against wiring faults that could lead to fire.
- Renewable Energy Systems: Critical for safety in solar PV installations and wind turbine control systems.
- Water & Wastewater Treatment: Protecting pumps and controls in damp, corrosive environments prone to insulation deterioration.
- HVAC Systems: Safeguarding large chiller and compressor units.
Beyond Basic Protection: The Minilec Advantage
Choosing the S2 ELR1 + CBCT isn’t just about buying a component; it’s about investing in a coherent, reliable safety solution. The relay and transformer are designed and tested together as a system, ensuring perfect compatibility and performance accuracy. This integrated approach from a single manufacturer eliminates guesswork, simplifies sourcing, and provides peace of mind that your safety system is engineered to work as one.
Conclusion: Don’t Wait for a Fault to Happen
Electrical safety is not an area for compromise. Ground faults are unpredictable, but your defense against them shouldn’t be. The Minilec S2 ELR1 + CBCT system offers a sophisticated, adaptable, and robust method to proactively manage risk.
By providing early detection and reliable isolation of leakage currents, it forms an indispensable part of a comprehensive electrical safety strategy, helping you comply with safety standards, prevent downtime and most importantly create a safer environment for everyone.
Ready to specify smarter protection? Consult with your electrical engineer or contact Minilec to integrate the S2 ELR1 Earth Fault Monitoring system into your next project or safety upgrade.
