You can purchase a copy of UL 508A 3rd Edition from the UL website or other standards distributors. Here are some options:
The 3rd Edition introduced several critical updates to align with the National Electrical Code (NEC) and NFPA 79. Major revisions include: Ul 508a 3rd Edition Pdf
: Certain changes, such as certification requirement changes for panels certified for Canada, have future effective dates reaching into October 2026 . Compliance Resources You can purchase a copy of UL 508A