The advantage of a Bypass-Isolation Automatic Transfer Switch over the standard Automatic Transfer Switch is that it enables the transfer switch to be completely isolated from the power system and safely tested or serviced without interrupting the power to the loads.  This is done by closing the isolation contacts in series with the transfer switch contacts (closed in normal operation) before opening of the transfer switch contacts. Please see the below operation of the Bypass-Isolation Switch.

Bypass-isolation switches are used in facilities such as healthcare, airports, water treatment plants, data centers, continuous flow industrial processes, correctional facilities, and high-rise office buildings.  When testing or maintenance programs are mandatory such as for facilities where an emergency power system exists, it may not be possible to de-energize the switch for a long period.







For further information the Application and Design Factors for Automatic Transfer and Bypass-Isolation Switches, please refer to the link below.

Part 1:
https://download.schneider-electric.com/files?p_enDocType=White+Paper&p_File_Name=asc-ts-wp-design-factors-p1.pdf&p_Doc_Ref=TS-WP-DESIGNFACTORS1

Part 2:
https://download.schneider-electric.com/files?p_enDocType=White+Paper&p_File_Name=asc-ts-wp-design-factors-p2.pdf&p_Doc_Ref=TS-WP-DESIGNFACTORS2

Published for:ASCO Power Technologies USA