ASCO 300 Series Automatic Transfer Switch

Where would your business be without a constant supply of electrical power? A steady power supply is often taken for granted. The reality is that power failures happen more frequently than we think.

In the event of a power interruption, an ATS switches power from commercial sources to the emergency backup anywhere from 30 to 60 milliseconds. The average human eyeblink happens in 400 milliseconds.

ASCO Power Transfer Switches with control logic monitors normal power supply and senses any fluctuations and possible interruptions. Applications for ASCO Automatic Transfer Switches are seemingly limitless. Any commercial enterprise that depends on electricity for operations can benefit from the 24/7 peace of mind that ASCO Power Management products afford you. In telecommunications for example, service providers are relied on for high level of service and dependability. Lost power means an interruption in service and lost profit.

ASCO Automatic Transfer Switches are available in several specifications depending on your specific business needs.

300 Series


Control & Display Panel

  • Easy-to-read flush-mounted control and display panel provides LED indicators for switch position and source availability. It also includes test and time-delay bypass switches

Voltage & Frequency Sensing

  • Adjustable three-phase, close-differential voltage sensing on normal source

Time Delays

  • Adjustable time delay to override momentary normal source outages to delay all transfer switch and engine-starting signals

Standard Selectable Features

  • Inphase monitor to transfer motor loads
  • Engine exerciser to automatically test backup generator
  • Selective load disconnect
  • 60 Hz or 50 Hz selectable switch, three-phase/single phase selectable switch

Remote Control Features

  • Remote test switch
  • Remote contact for test or for peak shaving applications
  • Remote time-delay bypass switch

Performance Features

  • 600 volt spacing per UL and CSA standards
  • Industrial grade interfacing relays
  • Meets and exceeds EMC requirements

Optional Accessories

  • 11BG-programmable engine exerciser
  • 14AA/14BA-auxiliary contacts
  • 44A-120 volt strip heater kit
  • 44G-208 to 480 volt strip heater kit
  • 72A-serial module with or without power manager
  • 72E-connectivity module with or without power manager
  • 123-Window kit