From Bends to Drainage: The Latest NEC Changes Every Installer Should Know

Every three years, the National Electrical Code (NEC) is updated, and the industry simultaneously reacts with excitement, complaints, and celebration. This article highlights the changes to conduit and tubing wiring methods recognized by the NEC. While updates to wiring method requirements might not generate as much emotion as changes to ground fault circuit interrupters (GFCIs) and arc fault circuit interrupters (AFCIs), they remain important to understand.

Dealing with damaged conduits: Sec. 300.4(C)

A new subsection under Sec. 300.4 clarifies that wiring methods or conductors damaged by water, fire, overloading, or corrosion must be replaced. This update comes from debates about reconditioning electrical equipment, introduced in the 2023 NEC under Sec. 110.20. While certain electrical components can be reconditioned under strict conditions, most wiring methods and conductors, especially conduit systems, cannot. Restoring a damaged conduit to a safe, Code-compliant state is often impractical. By adding this requirement to Sec. 300.4, the NEC clarifies that damaged conduit systems should not be salvaged but replaced.

Preventing condensation in raceways: Sec. 300.9

Raceways passing through temperature-differentiated spaces have long posed challenges because condensation can accumulate and affect the insulation of conductors. Section 300.9 has been updated to include an additional method for addressing this issue. Traditionally, sealants were required to prevent warm air from entering colder parts of the raceway. Now, a new provision permits the use of listed fittings designed to prevent warm-air movement and condensation. An Informational Note highlights thermal break couplings as an example. This change offers installers more flexibility while ensuring raceway interiors stay dry and safe.

Managing moisture in indoor wet locations: Sec. 300.11(B)

While outdoor wet location requirements for raceways are well established, indoor wet locations received less attention in earlier editions of the NEC. Section 300.11 was introduced in a previous cycle to address this gap, and the 2026 NEC further strengthens it. Raceways located aboveground in wet indoor environments must now be designed to allow for drainage. This change aligns with the long-standing requirements in Sec. 225.22, which already mandates drainage for outdoor wet-location raceways. Installers can meet this new requirement using the listed drainage fittings or by ensuring that connected enclosures include weep holes.

No more welding: Sec. 300.20(B)

Welding has sometimes been used in the field to support or join raceways, but this practice introduces several risks. Weld quality can vary widely, making it difficult to verify both structural and electrical integrity. Poor welds may harm conductors during installation, and, most importantly, raceways are not listed for welded connections. Earlier editions of the NEC allowed welding if the systems were “designed” for it, but this language was vague. The 2026 NEC eliminates that exception. Now, welding raceways is explicitly prohibited, with no exceptions. This change removes ambiguity and encourages safer, more standardized installation practices.

Clarifying bending rules across raceway types: Sec. 300.24

It has long been understood that the total amount of bends between pull points must not exceed 360°. However, this rule was previously scattered across individual raceway articles, such as Sec. 358.24 for electrical metallic tubing (EMT) and Sec. 344.24 for rigid metal conduit (RMC). The 2026 NEC addresses potential loopholes by adding a broad requirement in Sec. 300.24. It clarifies that the 360° limit applies to any combination of conduit or tubing raceways in a single run. This prevents installers from exceeding the limit by switching materials mid-run — for example, using 360° of EMT followed by 360° of RMC. The new wording emphasizes that the bend limit is cumulative, regardless of the type of raceway.

Corrosion protection clarified: Sec. 342.10(B)

Intermediate metal conduit (IMC) is often used in corrosive environments, such as concrete encasement or underground installations. Section 342.10(B) confirms this usage but includes an informational note explaining what qualifies as acceptable corrosion protection. Galvanized or PVC-coated steel is provided as an example. While this does not alter the actual requirements, it helps clarify the rules. For example, standard galvanized IMC already meets corrosion resistance standards because of its zinc coating and usually doesn’t need extra protection unless special conditions require it.

Addressing dissimilar metals: Sec. 342.14

Galvanic corrosion can happen when different metals contact each other in moist environments. The 2026 NEC addresses this by listing acceptable combinations for stainless steel IMC. It can be used with stainless steel fittings and enclosures or with coated steel boxes and enclosures in non-corrosive areas. A new option in the Code is the use of “identified bimetallic couplings,” which are specially designed to connect dissimilar metals without causing galvanic action. These special fittings are under development and must be listed for this use. This update finds a balance between durability, cost, and practicality, allowing hybrid raceway systems in suitable settings.

Securing threads at enclosures: Sec. 342.29

When a threaded conduit enters an enclosure through an unthreaded opening, there is confusion about how many locknuts are needed. The 2026 NEC now requires a locknut or fitting on both sides of the enclosure. This rule applies only when conduit threads go directly into the box — not when threadless fittings or threaded hubs are used. This update ensures mechanical continuity and electrical bonding and helps prevent misinterpretations of older Code language. A similar update is found in Sec. 344.29 for RMC.

Tightening all fittings: Sec. 342.42

Before the 2026 revision, Sec. 342.42 focused on threadless fittings, requiring them to be tightened properly and to be concrete-tight when installed in masonry and listed for wet locations when applicable. The revision broadens this language to include all couplings and connectors, not just threadless types. This includes threaded fittings like unions and three-piece couplings. The requirement to make all fittings up tight and to ensure listing for the relevant environment emphasizes the importance of secure, Code-compliant connections. This same update appears in Sec. 344.42. It is important to note that a straight thread coupling is not listed as a fitting; it is listed as part of the conduit itself. These couplings are not required to be listed for wet locations because the conduit itself is permitted in wet locations, and the coupling is just part of it.

Expanding PVC conduit size limits: Sec. 352.20

Polyvinyl chloride conduit (PVC) has traditionally been limited to a maximum trade size of 6. The 2026 NEC introduces an exception permitting larger sizes under specific conditions.

1. The conduit must be entirely underground.
2. It must be backfilled with the cover required by Sec. 300.7.
3. It must not be located in hazardous (classified) areas.
4. It must comply with Chapter 9 conduit fill requirements.

Currently, conduits larger than trade size 6 PVC conduit are available on the market, but they can only be used where listing is not required (e.g., electric utility installations). For this exception to become widely applicable, updates to product standards and Chapter 9 tables will be necessary. When those standards are revised, the Code is now ready to support larger conduit sizes, potentially providing benefits for high-capacity underground installations.

The 2026 NEC introduces a mix of clarifications, new allowances, and stricter prohibitions for conduit and tubing wiring methods. While some changes close long-standing loopholes, others add forward-looking flexibility. From banning welding on raceways to preparing for the use of oversized PVC, these updates reflect the NEC’s dual goal: ensuring safety and promoting innovation. For installers, designers, and inspectors alike, understanding these revisions is essential for maintaining compliance and protecting electrical systems.