Reliable power for a sustainable world
Current Range: 100 - 800 A

Static Transfer Switch


Installing a Master Switch static transfer switch provides additional resilience and protection from the disruption that can be caused by the failure of a single power source. The result is the absolute protection of industrial utilities and critical information technology against power supply and load faults.


  • High reliability

  • Hot Replacement function

  • 3- or 4-pole version

  • Advanced communications

Brochures and data sheets

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Master Switch STS Three-phase

100-800 A Static Transfer Switch

Technical specifications of the model

Operating principle 
Master Switch guarantees a source of redundant power, allowing the load to be switched between to alternative and independent power sources.  
Switching can be automatic (when a supply source falls outside of acceptable tolerances) or manually done by an operator from the front panel or remotely.

Protection against power failures
If one of the two power sources falls outside tolerance levels, Master Switch will transfer the consumers to the second power source (switching is instantaneous if the two sources are in phase).

Protection against environmental disturbances
Overloads and load faults 
In the event of an overload, the user can decide the level of intervention of the internal protection devices in order to block the power supply. In the extreme case of a downstream short circuit, Master Switch disconnects the load in order to avoid jeopardising the operation of the other loads (i.e. in the event of poor selectivity of the protection devices).

The layout of the moving components and parts is designed to ensure easy frontal access:

  • power cable connections that are easily accessed with entry from below;
  • boards housed in a dedicated area for rapid diagnosis / replacement;
  • all parts subject to monitoring, maintenance and/or replacement.

Advanced communications
​Master Switch provides information, measurements, statuses, and alarms via the LCD display. The STS is compatible with PowerShield3 supervision and shutdown software for Windows operating systems 10, 8, 7, Hyper-V, 2019, 2016, 2012, and previous versions, Mac OS X, Linux, VMWare ESXi, Citrix XenServer and other Unix operating systems.