Liebert STS2 Static Transfer Switch


Liebert STS2 Static Transfer Switch

Automatic Switching Between Critical Loads and Two Independent UPS Systems

For maximum availability applications, Liebert STS2 static transfer switch provides an automatic, seamless transfer between your critical load and the outputs of two independent UPS systems in a dual-bus power configuration. If the primary UPS should fail, the switch will automatically transfer the loads to the alternate UPS.

The Liebert Static Transfer Switch 2 (STS2) is available in 100A, 250A, 400A, 600A, 800A and 1000A sizes, 60Hz or 50Hz field selectable. Multiple input voltages are available. The system provides an automatic, seamless transfer between the outputs of two independent UPS systems and the input of a critical load in a dual-bus power system.

  • Automatic switching for dual bus loads
  • Requires only front-only access, for easy installation and maintenance
  • Offers primary or secondary side switching
  • Operates energy efficiently


  • Front access to all components provides simplifies installation and maintenance, and reduces amount of floorspace required for access.
  • Internal CANBUS protocol: high-bandwidth communication between system components via twisted-pair cables. Options can be added as simple network nodes.

Higher Availability

  • Triple redundant logic with dual power feeds.
  • Standard on-unit monitoring and optional centralized monitoring capability provide continuous system visibility.
  • 100% rated, fuseless design.
  • Hot-swappable circuit breakers.
  • Flash memory enables firmware updates while supporting critical load.
  • Rack-out control/power assembly on units up to 600A to allow maintenance, service or full replacement without disrupting the critical load.

Lowest Total Cost Of Ownership

  • When applied as primary side switching, cost are lower due to requiring only one power distribution unit, a lower current due to 480V vs. 208V, and lower installation and wiring cost.

Ideally Suited For

  • Data centers
  • Telecommunications
  • Industrial process equipment
  • Laboratories

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Power Management Product
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Liebert STS2 Optimized Transfer Video
Maximum Protection: See how the optimized transfer feature of Liebert STS2 static transfer switch eliminates excessive currents when transferring between out-of-sync sources.
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