Selecting the Most Reliable Electrical Contacts for Circuit Breaker Applications

Circuit breakers are critical components in electrical systems designed to protect circuits by interrupting current flow . Failures are often attributed to issues with electrical contacts, which play a central role in circuit breaker functionality. This blog offers practical insights into the selection of optimal electrical contacts to ensure effective circuit breaker performance.

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The Role of Optimal Performing Electrical Contacts in Circuit Breakers

Electrical contacts enable the controlled interruption and restoration of current flow. Their performance is influenced by:

Material Composition: High-conductivity materials such as silver and copper are widely used for their durability and low resistance properties.

Mechanical Integrity: Proper alignment and consistent contact pressure ensure reliable operation.

Environmental Factors: Moisture, dust, and corrosive substances accelerate contact degradation. Coastal and industrial settings pose additional risks due to humidity and pollutants ( Antler, M. (1987). Effect of Surface Contamination on Electric Contact Performance. In: Mittal, K.L. (eds) Treatise on Clean Surface Technology. Springer, Boston, MA.)

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A. Common Causes of Circuit Breaker Failures

1.  Material Wear

Electrical contact performance degrades overtime due to arcing, repeated use, and mechanical stress. This gradual wear can vary based on operating frequency, environmental conditions, and maintenance practices. Monitoring signs of wear, such as surface roughness or reduced conductivity, is essential (Electrical Contact Design for Reliable Circuit Breakers, IEEE, 2019).

2.  Overheating

Increased resistance in corroded or worn contacts generates localized overheating, which can lead to damage. Overheating is commonly observed in high-current loads, environments with poor ventilation, or systems operating beyond recommended capacities. For more information, visit this resource: (https://ecampusontario.pressbooks.pub/electrotechnology/chapter/part-3-circuit-breaker-operation/)

3.  Mechanical Stress

Misaligned or improperly tensioned contacts hinder current transfer, potentially causing erratic performance or permanent failure (Li, X., Zheng, X., Zhang, T. et al. Robust fault diagnosis of a high-voltage circuit breaker via an ensemble echo state network with evidence fusion. Complex Intell. Syst.9, 5991–6007 (2023).

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B. How to Diagnose Contact Issues

1.  Visual Inspection

Inspect for pitting, corrosion, or discoloration that indicates degradation.

2. Thermal Imaging

Utilize thermal imaging tools to identify hotspots on contacts, which can indicate increased resistance or compromised connections.

3.  Electrical Testing

Measure resistance across contacts to verify compliance with specifications at:https://blog.ansi.org/ansi-neta-mts-2023-testing-specifications-power/ .

4.  Operational Testing

Simulate fault conditions to confirm the circuit breaker’s ability to trip as designed.

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C. Selecting Durable Electrical Contacts

Material choice directly affects the reliability and lifespan of circuit breakers:

·    Silver Alloys: Provide superior conductivity and resistance to oxidation (Advances in Silver-Based Electrical Contacts,Materials Science Journal, 2019).

·    Tungsten Composites Resist high temperatures and arcing, making them suitable for demanding environments (High-TemperatureResistant Materials for Electrical Applications, Springer, 2020).

·    Silver-Tungsten Blends: These blend high conductivity with wear resistance, making them ideal for applications such as industrial power systems and heavy-duty switching (Material Engineering for Electrical Systems, Wiley, 2018).            

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D. Preventing Failures Due to Faulty Electrical Contacts

1.   Regular Maintenance

Perform routine inspections to identify and clean contaminants that may impair contact performance.

2.   Invest in Quality Materials

Use electrical contacts that meet stringent industry standards to ensure durability and reliability.

3.   Environmental Controls

Install circuit breakers in well-maintained environments to mitigate exposure to harmful conditions

4.   Adhere to Operational Guidelines - Follow manufacturer-recommended usage practices to reduce stress on contacts.

5.   Proactive Replacement -Replace worn contacts during scheduled maintenance to prevent unexpected failures.

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What's Next for Electrical Contacts in Circuit Breaker Applications?

Electrical contacts are integral to circuit breaker functionality and reliability, which can be optimized by adopting preventive measures, selecting appropriate electrical contact materials, and requiring high-quality standards in both the electrical contacts and the OEM circuit break device.

Contact Checon to learn about its success in delivering the most reliable electrical contacts available today for circuit breaker applications.