What are dual power inputs and why are they important?

Industrial switches often provide dual (redundant) power inputs allowing simultaneous connection to two independent power sources.

How Dual Power Works

• Both inputs powered simultaneously (active-active) or one active/one backup
• Internal diode-OR or switching circuit selects healthy source
• Failover is instant (no packet loss)
• Typical input types: 12-48VDC, 24VDC, 110-220VAC, or 88-300VDC

Benefits

• Power source failure protection: Continue operation if one PSU fails
• Battery backup integration: Primary from AC, secondary from UPS/battery
• Circuit isolation: Different power circuits for redundancy
• Maintenance without downtime: Service one path while other operates

Common Deployment Scenarios

• Substations: DC battery + AC feed
• Roadside cabinets: Main grid + solar/UPS
• Trains: Two independent car circuits
• Wind turbines: Primary + emergency circuit

Design Considerations

• Voltage compatibility: Both inputs must be within switch's range
• Independent sources: Two circuits from same panel offer little benefit
• Power alarm outputs: Alert when one input fails
• Wire gauge: Match to inrush current draw

Alarm Contact

Most industrial switches include a dry-contact relay that opens on failure alerts (dual power lost, temperature exceeded, port down). Connect this to your alarm system.