Code Change Summary: Requirements all throughout Article 645 for information technology (IT) equipment have seen extensive changes.

With all of the new code changes in Article 645, electricians installing or working in IT rooms would do best reading all 4 pages of Article 645 from beginning to end to become familiar with the new revisions. Below are some highlights:

• The rules in 645.3(B) pertaining to wiring and cables used in a plenum have been changed into a list.
• Rules pertaining to fire alarm cables in 645.3(E), communications cables in 645.3(F) and CATV cables in 645.3(G) have been changed to make it clear that only specific fire alarm, communications and CATV cables are permitted in the IT room.
• Section 645.3(H) was added to include requirements for optical fiber cables in IT rooms.
• Permitted wiring methods under raised floors in IT rooms have been formatted into a list in 645.5(E).
• Table 645.5(E)(6) was removed and tuned into a list which included the deletion of wire types NPLFR, FPLR, NPLF, FPL, CATVR, and CATV since they are no longer permitted under raised floors.
• New Table 645.10(B)(5) was added to provide references to applicable code sections for cables installed under raised floors in critical operations data systems.
• New Section 645.18 requires surge protection for critical operations data systems.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2017 NEC^® edition of NFPA 70.