ASCO Three-Source Priority System

ASCO Three-Source Priority Systems are similar to the ASCO three-source systems except they protect two critical loads rather than one critical load. Upon the loss of the utility power source, the system provides all necessary controls to start both alternative power sources.

  • Priority selector transfer switch.
  • Control logic for selecting between alternate power sources.
  • Normal, emergency, and/or load circuit breakers.
  • Protective relaying (as required).
  • Optional instrument meters for normal, emergency, or load for local monitoring.
  • Designs are based on NEMA and UL 891 standards.
  • Optional engine start control logic and/or load control logic.