Dry Contact

  • A dry contact is a mechanical switch that does not provide voltage or current. It only acts as an open/close switch.
  • Volt-free, potential-free, or passive contact
  • External power must be supplied by the controller or circuit that reads the contact.
  • Relay contacts

Wet Contact

  • Powered Contact
  • A wet contact includes a voltage source, meaning it supplies or switches a voltage signal (e.g., 24VDC or 230VAC).
  • Active contact
  • The contact itself supplies voltage when it closes.
  • A sensor that outputs 24VDC when triggered.
  • Sensors (e.g., proximity switches)