Understanding the 2026 NEC Changes to Article 645

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Article 645 of the National Electrical Code has always been a source of debate, mostly because of the way it handles emergency power off requirements in information technology equipment rooms. For years, designers who wanted to avoid installing the big red emergency power off (EPO) button have taken advantage of a specific section that allowed them to “design out” of the rule. The upcoming 2026 NEC keeps the intent of Article 645 but moves some key language and updates the cross references. Anyone who enforces or designs according to this article needs to know exactly what changed and what did not.

What 645.4 said in the 2023 NEC:
In the 2023 edition, Section 645.4 spelled out the trade-off. It permitted alternative wiring methods, shortcuts to the standard Chapter 3 wiring rules and to the signaling and optical fiber wiring rules in Articles 725 and 770, if six specific conditions were met. These conditions required:

• a disconnecting means that it complied with 645.10
• a dedicated HVAC system or a shared system with smoke dampers that close when the disconnect is operated or when smoke is detected
• all ITE and communications equipment in the room to be listed
• the room to be occupied and accessible only to personnel needed for maintenance and operation
• fire resistance separation from other occupancies
• only equipment associated with the operation of the ITE room to be installed inside

The practical effect was simple. If you did not need the alternative wiring allowances and you built the room to fully meet the standard Chapter 3 and Chapter 7 wiring methods, you were not required to follow Article 645 at all. That meant the emergency power off in 645.10 did not apply. This “opt out” provision is what allowed many projects to avoid the EPO requirement.

2026 Draft: 645.4 Disappears
In the 2026 draft, section 645.4 is gone, but the substance is not. The same six conditions are now located in 645.5 with updated references:

• The old references to Chapter 3, Article 725, and Article 770 are replaced with new references to Article 722, specifically 722.120 for signaling wiring and 722.160 for optical fiber cabling.
• The language of the conditions themselves is virtually unchanged.
• The informational notes have been updated to match the latest editions of NFPA 75.

Why It Matters
The reorganization does not change the ability to design out of Article 645. The path is simply relocated. If a designer chooses to build the IT space to standard Chapter 3 wiring methods and does not claim the alternative wiring allowances now described in 645.5, then Article 645 and with it the 645.10 emergency power off requirement does not apply.

The Takeaway​

Do not assume the 2026 NEC tightened the rules on emergency power off. It did not. What used to be 645.4 is now 645.5, with cross references updated to the new Article 722. The long-standing debate remains the same. Before enforcing 645.10, confirm whether the project is using the alternative wiring allowances. If the answer is no, the requirements of Article 645, including the EPO button, are still optional.

 

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An admission.

For years, I enforced 645.10, and although I got some arguing and pushback, not once did a designer or engineer cite the fact that they were compliant with Chapter 3. I was wrong, but so were they because they did not even know Article 645 existed. That experience shows how easy it is for both sides to miss the real trigger that decides whether 645.10 applies.