The 2026 edition of the National Electrical Code (NEC) is the result of nearly 4,000 public inputs (formerly called “proposals”) and just fewer than 2,000 public comments. Hundreds of changes were made, and over the next several issues we plan to cover some of the most important ones. In this edition, we focus on a few key changes made to Chapter 3.

Section 300.4, Limitations

Damaged conductors and wiring methods must now be replaced.

This Section was added mainly as a way to deal with the reconditioning of wiring methods and conductors. Reconditioning those products is probably not physically possible. Instead of covering the subject dozens of times throughout Chapter 3, it was deemed a better solution to place the material here.

In the 2023 NEC, Sec. 110.20 specified that reconditioned versions of all equipment could be installed, unless the Code said otherwise. There was much debate over whether the definition of “equipment” includes wiring methods and conductors. If wiring methods are damaged, they need to be replaced. Reconditioning them is probably not a realistic option, even if the Code allowed it.

The two Informational Notes point to two NEMA guidelines, available at www.NEMA.org. As the notes clearly indicate, these papers can help a person determine if equipment needs to be replaced after it is damaged.

Section 300.20, Raceway Installations

Welding raceways is now prohibited, without exception.

This Section has long indicated that terminating, supporting, or connecting a metal raceway by welding was generally not allowed. This section allowed welding if “allowed elsewhere” in the NEC (there is no such allowance anywhere in the Code) or if it was specifically designed to be welded. The previous language also raised an obvious question: which designer had the authority to make that determination? The designer of the product? The designer of the building? The contractor that designs the conduit installation?

Welding a raceway creates several concerns. The quality and integrity of a weld are very difficult to verify. Any weld that is less than perfect could easily damage the contained conductors when they are installed. The raceway is also not listed to be welded. How a welded raceway would handle thousands of amperes of current during a ground fault is not known. Revisions to Sec. 300.20(B) make it very clear that raceways are not to be welded — period (Photo 1).

Section 310.5, Conductors

Smaller sizes of copper and copper-clad aluminum conductors are now allowed for general applications.

During the 2023 NEC revision cycle, there were several coordinated proposals to allow smaller circuits and smaller conductors for lighting circuits. Some of those changes passed, but others did not.

Article 210 was revised to allow 10A branch circuits for supplying lighting loads, exhaust fans, or individual loads on their own circuit (provided a receptacle was not used). Article 240 was also revised to tell the code user which size wire could theoretically be used on these smaller circuits and how to protect them from overcurrent. Article 310, however, has the final say on the minimum conductor size that is allowed to be installed. What was Sec. 310.3 (now Sec. 310.5) was not changed to allow smaller wires. This was perhaps the single most controversial subject in the 2023 revision cycle, with one side of the debate insisting that more data was needed and the other side insisting that the necessary data was already provided. In the end, the 2023 NEC did not allow conductors smaller than 14 AWG copper or 12 AWG copper-clad aluminum.

For the 2026 NEC, the requested data was provided, and the Code was changed. Now a 16 AWG copper or 14 AWG copper-clad aluminum conductor can be used on the 10A branch circuits discussed in Part II of Art. 210, and a new Informational Note was added to guide users to that part of the Code. Readers should note that although the Informational Note points only to Sec. 210.23, it is also worth reading Sec. 210.22 for additional context. Section 210.23 addresses branch circuits with more than one outlet; Section 210.22 addresses individual branch circuits. While a 10A multioutlet branch 
circuit is only allowed for luminaires and exhaust fans, an individual 10A circuit is allowed for any load up to 10A, provided it is not cord and 
plug connected.

It may be of interest to the reader to note that this change was not only the most hotly debated subject for the 2023 revision cycle, but also the 2026 revision cycle. This change (and other associated changes) were appealed, and the matter was not settled until only a few days before the printing of the 2026 NEC.

Section 312.11, Enclosures with Switches or Overcurrent Protective Devices

New restrictions apply to service conductors passing through enclosures that contain switches or overcurrent protective devices.

This change prohibits service conductors from passing through enclosures that contain circuit breakers or switches but are not the service equipment. 

There is a requirement in Sec. 230.7 that indicates that service conductors may not occupy the same raceway — including wireways — as conductors that are not service conductors. That rule ensures that the service conductors cannot fault to a feeder circuit because such a fault would bypass the feeder’s OCPD and result in energized conductors even with the breaker turned off.

There has never been a requirement that addressed the same hazard in enclosures — until now. Within the service equipment, service conductors may be spliced, tapped, or pass through the enclosure. This is needed because splicing a PV system onto the service conductors is an extremely common practice and should not be prohibited. It is worth noting that this rule only applies to enclosures that contain switches or fuses, so splicing or feeding through a CT enclosure or meter socket enclosure is still allowed, although the local utility may not allow it (Photo 2).

Section 314.27, Outlet Box Installation and Ratings

The requirements for fan boxes in dwelling units were clarified and reduced.

This Section has been the subject of several changes and much controversy over the last several Code revision cycles. If a box supports a fan, the box must be rated for that purpose and must be marked to indicate that fact. Problems arise when “regular” boxes are installed for “regular” luminaires in areas that are likely to have a ceiling fan eventually.

It was not uncommon for a production homebuilder to install a “regular” box in the middle of a bedroom ceiling and install two switch legs for it. They would then advertise this installation as suitable for a “future” ceiling fan, despite the noncompliant box. That issue was resolved a few years ago by requiring such a box to be rated for ceiling fans, despite a fan not being installed yet. Modern ceiling fans, however, no longer require two switch legs to activate the illumination and the motor independently, so that revision no longer solved the problem.

In the opinion of many, the Code then went too far by requiring nearly every box in any habitable space of a dwelling to be rated for ceiling fans. For example, three pendants installed above a kitchen’s peninsular countertop needed to have three ceiling fan boxes, despite the impossibility of all three being replaced by ceiling fans.

This Section now limits the application of this rule to sleeping rooms and living rooms (not kitchens and similar) and to areas that are indicated for ceiling fan use.

Section 334.2 Listing Requirements

The listing requirements for cable accessories were expanded.

Cable ties have had a listing requirement in this Article for a few years. This makes sense because not all cable ties are created equal. A listed cable tie can be listed for cable management (Types 1, 2, 11, and 21), or it can be listed for securing and supporting cables and flexible raceways (Types 2S and 21S). For that reason, cable ties need to be listed and identified for securing and supporting.

New to the 2026 NEC, hangers, staples, and straps must also be listed. The substantiation for this change appears to have been based largely on the existence of a product safety standard for hardware used for securing wiring methods. It is worth noting that Sec. 334.30 does not include the “other approved” option found in other cable articles, so only listed products are permitted for securing and supporting NM cable. Considering the ease of damaging the nonmetallic sheath of NM cable when compared to the metal jacket of AC or MC cable, this change seems to be a bit more important than the ones in Sec. 320.2 and Sec. 330.2, respectively.

The same change occurred in several of the cable wiring method Articles (Photo 3).

Section 344.42 Couplings and Connectors

The requirements for couplings and connectors were editorially revised, and all fittings must now be tightened.

Previous versions of this Section applied only to threadless fittings. It is important to know that the typical RMC or IMC coupling is not a fitting. It is part of the conduit itself. These straight threaded couplings are listed to UL 6 (RMC) or UL 1242 (IMC), and not UL 514B (fittings).

This means that this rule never applied to the standard coupling, and it still does not. It only applied to threadless fittings, such as set screw or compression couplings and connectors. However, there are threaded fittings that truly are fittings. What about a three-piece fitting or a union? Those are fittings, but they are not threadless fittings. What are the rules for them? There weren’t any. Now they must be made up tight, and they must be listed for wet locations or concrete-tight when needed.