NEC 2026 Update: How 5 Inches of Concrete Can Impact Your Projects

By Arjun Srinivasan, Fire Protection Market Manager, and Chase Erford, Technical Sales Specialist, Specialties, Prysmian North America

The latest 2026 National Electrical Code (NEC) has a major change for emergency power systems and standby circuits. To achieve a 2-hour fire-resistance rating, the NEC now requires 5 inches of concrete encasement around feeder conduits—a big jump from the previous 2-inch minimum.

What Does This Mean for Your Projects? 

This change is not just a small tweak or quick fix. Going from 2 inches to 5 inches of concrete encasement can add significant cost, labor, and complexity to your projects

• Higher Material Costs: Using extra concrete means higher costs, and possibly structural and design changes
• Slower Installs: Pouring and curing that much concrete takes time, especially if you are working on retrofits or in tight spaces.
• Design Headaches: Five inches of encasement can impact existing designs and specifications, leading to redesigns and rework. 

All these issues can lead to bigger budget issues and schedule delays, particularly for critical projects like hospitals, data centers, and high-rise buildings.

Why the NEC Made This Update

The old 2-inch standard just couldn’t withstand fire testing. Under ASTM E119 conditions, 2 inches often failed to keep conductors intact for two hours. However, 5 inches, no matter the type of concrete, gets the job done. Safety is the goal—but efficiency is critical for these installs, too.

UL 2196 Fire-Resistive Cable is the Smarter Alternative

There is, however, an easier way to stay compliant amidst this code update that does not require concrete at all. UL 2196-listed fire-resistive cables, such as Prysmian’s Lifeline® fire-resistive cable systems, provide ultimate flexibility and the same 2-hour protection without the need for complicated designs. This means you can save on material and labor costs, simplify design work, and fit into tight spots where concrete encasement is not practical. 

This 2026 NEC update is all about safety, but you do not have to let it slow you down. By using Lifeline® fire-rated cable systems, you can stay compliant, save time, and keep your installs on budget. For contractors who want to avoid the headaches of concrete encasement, Lifeline® is the smart choice over concrete encasement. 

Check out our Lifeline® technical resources here or contact Prysmian’s Lifeline® team at [email protected] to learn more.