CuNi20 Sheet (UNS C71000) for LV Circuit Breakers Shunt Resistor Grade

CuNi20 Sheet (UNS C71000) for Low-Voltage Circuit Breakers | ±30ppm TCR | 100kA Interrupt | IEC 60947/ASTM B122 Applications: Molded Case Breakers • EV Charging Contacts • Shunt Resistors • Busbar Terminals

MATERIAL TECHNOLOGY

Alloy Composition (ASTM B122):

• Cu 79-81% | Ni 18-20% | Fe 0.5-1.0% | Mn 0.3-0.8%
• Density: 8.94 g/cm³ | Melting Range: 1100-1150°C Critical Properties:
• Resistivity: 34 μΩ·cm at 20°C
• TCR: ±30 ppm/°C (0-150°C)
• Thermal Conductivity: 29 W/m·K
• Sulfide Resistance: Zero tarnishing at 150°C/1000hr

CERTIFIED PERFORMANCE

ELECTRICAL RELIABILITY

• Contact Resistance: <15 μΩ·cm² (IEC 60413)
• Arc Erosion Rate: 0.08 mm/1,000 ops at 1kV/10kA (IEC 60947)
• Resistance Stability: ΔR/R <0.05% after 50,000 interruptions

MECHANICAL DURABILITY

• Hardness: 110-140 HV (Hard Temper)
• Fatigue Strength: 180 MPa at 10^(7) cycles (ISO 1099)
• Thermal Shock: -40°C↔150°C × 500 cycles

DIMENSIONAL SPECIFICATIONS

Standard Sheet (ISO 9444):

• Thickness: 0.5–12.0 mm (±0. %)
• Width: 100–600 mm (±0.1 mm)
• Length: 500–2500 mm (±1 mm/m) Surface Treatments:
• Mill Finish (Ra 1.6 μm)
• Passivated (Cr^(3+) oxide layer)
• Tin/Silver Plated (IEC 60413 compliant)

BREAKER-SPECIFIC ENGINEERING

Contact Performance:

• Welding Resistance: ≥800 N/mm² (UL 489)
• Arc Mobility: 20% faster than pure copper
• Current Density: 100 A/mm² continuous Shunt Resistor Capability:
• Voltage Drop: 3.4 mV/A·m
• Thermal Derating: 0.4%/°C above 100°C
• Self-Inductance: <5 nH/cm

INDUSTRIAL VALIDATION

ELECTRIC VEHICLES:

• DC Fast Charger Breakers: 1,500V/20kA clearance
• 0% contact welding at -40°C cold switching INDUSTRIAL AUTOMATION:
• MCCB Contacts: 100kA interrupt at 440V AC (IEC 60947-2)
• Short-Circuit Withstand: 100kA/100ms (IEC 60898) RENEWABLE ENERGY:
• Solar Combiner Boxes: 85% humidity endurance (IEC 61730)
• Wind Farm Switchgear: 15G vibration resistance

Normal composition%