How to Select the Right Silver Contact for Your Relay Design in 2025
Complete Engineering Selection Guide – Chende Factory

December 2025 | 72 min read | For Electrical Design Engineers

Step 1: Define Your Load Type and Current Rating

The first decision in silver contact selection is understanding your load profile. Resistive, inductive, lamp, motor, or capacitive loads behave differently under make and break conditions. According to IEC 60947-5-1, utilization categories AC-1 to AC-15 and DC-1 to DC-13 dictate material choice. For example, AC-15 (inductive control circuits) requires excellent anti-welding properties, while DC-13 (electromagnetic loads) demands superior arc quenching.

Step 2: DC vs AC Applications – Critical Differences

DC arcs are harder to extinguish than AC due to no natural zero crossing. For DC >30V/1A, silver graphite contact (AgC5–10) or silver tungsten contact (AgW) is mandatory. Chende’s AgC5 tri-metal design achieves 200,000+ operations under 60VDC/50A. See TE Connectivity DC Contactor Guide.

Step 3: Material Selection Matrix 2025

Current	Load Type	Recommended Material	Life Expectancy
<30A	Resistive/AC-1	AgNi10-30	100K–500K
30–100A	Inductive/AC-3	AgSnO2(12)	200K–1M
DC >30V	Motor/DC-13	AgC5	150K–500K
>500A	HV Breaker	AgW50-70	10K–100K

Full product range: Chende Silver Contact Products

Step 4: Environmental and Regulatory Compliance

EU RoHS Directive bans cadmium in new equipment. All Chende silver contact materials are RoHS and REACH compliant. For legacy AgCdO replacement, we offer direct drop-in AgSnO2 solutions. See EU RoHS Directive.

Step 5: Mechanical and Assembly Requirements

Rivet head shape (round, flat, conical), shank diameter, and welding method affect assembly efficiency. Chende provides over 200 standard silver contact rivet designs and full custom capability.

Step 6: Cost vs Performance Optimization

Use tri-metal design to reduce silver consumption by 40% while maintaining performance. Chende’s engineering team provides free FEA analysis for optimal material and geometry.

Step 7: Testing and Validation

Chende offers complete electrical life testing per customer specification, including temperature rise, contact resistance, and arc duration measurement using high-speed cameras.

FAQ for Relay Design Engineers

Which silver contact for automotive relays?
AgNi10/Cu bimetal for auxiliary, AgSnO2 for power relays. See automotive silver contacts.

Best silver contact for EV charging pile?
AgSnO2(12)+In2O3 doped, 200K+ cycles under 60A. Chende supplies major charging brands.

How to prevent DC welding in pre-charge relays?
Use silver graphite contact AgC5. Chende tri-metal design is standard in BMS systems.