Three 2026 NEC Changes That Might Surprise Experienced Solar Installers and Designers

Every three years, a new edition of the National Electrical Code drops, and with it comes a set of changes that practitioners need to get up to speed on before they show up in the field. The 2026 version is no exception.

Rebekah Hren, Brian Mehalic, and Alex Jahp of Solar Tech Collective walk through three changes worth noting. First, chapters six and seven have been renamed: “special equipment” and “special conditions” are now “specific equipment” and “specific conditions,” a small shift that signals a broader change in how those chapters are framed. Second, the rounding allowance that already existed for feeders and branch circuits has been extended to PV systems, energy storage systems, and interconnection calculations. Third, the allowance for using a documented stamp design, previously limited to systems 100 kW or larger, now applies to any system size.

The chapter renaming is more of a terminology update, but the rounding allowance and the documented stamp design expansion have real implications for how practitioners work in the field. 

Rebekah, Brian, and Alex cover these changes and much more in their course – Comprehensive 2026 NEC Requirements for Electrotech: PV, ESS, EVs, PCS, and More – available now on HeatSpring.

Enroll here!

Transcript below.

Brit: For someone who’s been designing or installing solar for a while, what would you say is the biggest single thing they might be surprised to find has changed in the 2026 NEC?

Rebekah: It’s super hard to pick out just one thing, but they might be surprised to see that chapters six and seven are no longer “special.” Chapter six was Special Equipment and chapter seven was Special Conditions, and now it’s “specific.” So you’ve got Specific Equipment and Specific Conditions. We’re a little sad that we’re not special anymore.

Brian: We’re still special. Come on. I think an interesting change is that for years and years, we were allowed to round calculations for feeders and branch circuits, but that didn’t necessarily apply to energy storage systems, PV systems, or interconnection. We got that allowance extended into Articles 705, 706, and 690, and it even applies to voltage in Article 690. So now we can do math the way a lot of people are used to doing it: round our numbers, drop decimals that are less than 0.5.

I’ve been involved with systems where that has made a real difference. A system that calculated out to 200.4 amps previously meant you needed a 250-amp piece of equipment. That’s no longer the case. It’s a practical extension of an allowance that already existed for other circuits and systems, now applied to the work we actually do.

Alex: For me, one of the most surprising changes was a new allowance for the use of a documented stamp design for any system size. Previously that allowance only existed for systems 100 kilowatts or larger, but now you can use it for any system.