The 7th Edition of UL 1008 became effective November 1, 2014 and has resulted in significant changes to the short-circuit ratings shown on all transfer switch products in the industry. UL 1008 is the “Standard for Transfer Switch Equipment” and it was issued by UL in 1972 to help ensure the safety of installation, operating and maintenance personnel who interface with transfer switch equipment.


UL 1008, 7th Edition: Withstand and Closing Rating Requirements