The 2026 edition of the National Electrical Code (NEC) is the result of more than 4,000 public inputs (formerly called “proposals”) and just under 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 of the key changes made to Chapter 4.

Section 408.6, Short-Circuit Current Rating

The marking requirements for switchboards, switchgear, and panelboards were greatly expanded.

Although this Section went from a small paragraph in 2023 to this rather large list in 2026, the practical ramifications may not be as significant as they initially appear. The general requirements of Sec. 110.9 and Sec. 110.10 already required what most of this change is intended to capture. All equipment must be rated for the available fault current, which is typically ensured by its short-circuit current rating (SCCR) or its interrupting rating being equal to or greater than the available fault current. However, the short-circuit current rating of the equipment covered in this Article is not necessarily a static number like it is for a “simple” piece of equipment like a non-fusible general-use switch.

Consider a panelboard that has a short-circuit current rating of 22,000A, for example. If the available fault current is only 8,000A, the panelboard will likely have circuit breakers with a 10,000A interrupting rating. Due to this, the panelboard’s effective SCCR is likely no longer 22,000A; it is 10,000A. New to this edition of the Code, that new value must now be written on the panelboard (Photo 1).

Section 422.12, Central Heating Equipment

The types of equipment allowed on the central heating branch circuit were expanded.

In many parts of the country, central heating equipment is a life-safety piece of equipment. For this reason, the NEC does not allow other equipment on that circuit. Exception No. 1 allows auxiliary equipment for the central heating appliance. Auxiliary equipment can include air cleaners and humidifiers, and now commonly includes germicidal irradiation luminaires as well. These luminaires are typically installed inside of the furnace’s plenum and cycle on and off to kill germs within the air-handling system. 

Instead of adding these special luminaires to the list of permitted items, the Code-Making Panel used the catch-all term “similar” to avoid inadvertently limiting the user by not including every type of equipment that could be considered auxiliary to the appliance (Photo 2).

The second Exception was also expanded to allow the lighting required by Sec. 210.70(A) and the receptacle required by Sec. 210.63(A). The lighting and receptacle are both necessary to aid in maintenance or repair of the appliance. The lighting outlet draws very little current, and the receptacle is likely to be used only for diagnostic equipment. As such, the total load is minuscule and is now allowed on the circuit. If one were to plug in a power tool, which consumes more power, to work on the equipment, one would hope that the appliance was de-energized; hence the new allowance.

Section 426.60, General

Conductive pavement heating systems were added to Art. 426 in the new Part VI (Secs. 426.60 through 426.88).

Inside conductive paving material, such as concrete, electrodes are placed at specific spacings. The electrodes are then energized at a voltage of up to 30VAC or 60VDC. This heats the pavement and melts any accumulated snow or ice.

Intentionally energizing a surface that people and other animals will be walking on has some obvious inherent safety concerns, but the requirements in this new Part of Art. 426 are very broad and stringent. One of the main reasons this material was added is because there were no existing limitations on devising such a system under the previous versions of the Code — and people have been doing just that. The submitter of this concept made the Code-Making Panel aware of “do it yourself” systems, including energizing concrete to 480V and putting no actual safety measures in place.

There are several unique requirements for these systems, including the design and oversight of both an electrical engineer and a civil engineer. As indicated in Sec. 426.2, these systems must be listed as a system. A hodgepodge of various equipment, even if listed, is not permitted for these applications. As of this writing, a product safety standard or outline of investigation does not yet exist but is currently under development. This means they will not be available immediately. These systems must also have a site-specific design, so do not look to buy one from your local hardware store.

Notably absent from the requirements is any sort of GFCI or even GFPE protection. That was intentional because that type of protective system will not function in these applications. Instead, lower voltages and an isolating, ungrounded power supply are used, much like some swimming pool lighting systems and the operating rooms of many hospitals.
Refer to the NEC for the full requirements for these systems, as there are many (Photo 3).

Section 430.7, Markings on Motors

Two new motor design types (BE and CE) were added throughout Art. 430.

The motor design types indicated in this Section allow the specifier or installer to ascertain a lot of information quickly if they are familiar with the design types. For example, if a person needs to buy a motor that is under load the second it starts (like a crane or a hoist), they will likely want a motor that is marked “Design D.” For an HVAC application, a “Design B” motor may be more appropriate.

Two new motor design types were added in the 2026 NEC, both added in response to the Department of Energy’s requirements for energy efficiency. It is important to note that, as of this writing, these motor types are still under development, and there is very little in the way of technical information about them. This technology and the associated requirements are sure to evolve over the next few years.

Multiple changes were made throughout Art. 430 for these new motors, including a new Sec. 430.22(H) and Table 430.251(C). One of the key differences with these new motors is the locked-rotor current — hence the new Table 430.251(C). When the motor is running, the current is not much different from that of an ordinary motor. Under locked-rotor conditions (startup), however, the current is much greater than shown in Table 430.251(B), which is why the new Table 430.251(C) was added.

Section 430.22(H) was added to give specific requirements for conductor sizing. If the motor is used in a continuous duty application, the conductors are sized at 125% of the motor’s FLC rating, just like a typical motor. If they are used in a different manner, such as intermittent, varying, or short-time duties, Sec. 430.22(E) applies, just like a typical motor.

But due to the very high inrush current (locked rotor), special requirements are needed to keep the conductors from experiencing excessive temperatures. The type of conductor medium (copper versus aluminum) as well as the insulation type (thermoset versus thermoplastic) need to be considered, as does the duration that the conductors are exposed to the starting current.

Protection from excessive heat can be achieved by employing an adjustable-speed drive system, a reduced startup voltage, or a wye-start delta-run configuration. If none of those are used, the equation in Sec. 430.22(H)(3) will need to be used. As that Section’s new Informational Note indicates, the equation could result in larger conductors than would otherwise be required.

Exception No. 4 to Sec. 430.24 provides a similar requirement for conductors serving multiple motors, one or more of which is Design BE or CE.

Table 430.52(C)(1) was also revised to include these new motor types. These motors are lumped in with Design B energy-efficient and Design B premium efficient motors. When using a fuse or inverse time circuit breaker, the ground-fault and short-circuit protective device ratings are still the same as most other motors.

However, if an instantaneous trip breaker (aka motor-circuit protector or magnetic only) is used in conjunction with a listed combination motor controller, the maximum rating can be 1,100% of the FLC instead of the standard 800% for other motors using the same protective device.

The “failure to start” Exception in that Section also allows a whopping 1,700% maximum if the table values will not allow the motor to start [Sec. 430.52(C)(3)(b)(2)]. Considering that the main concern with these motors is startup current, that allowance might prove necessary.

Section 430.132, GFCI and SPGFCI Between Motor and Power Conversion Equipment

A new Section was added to address GFCIs and SPGFCIs between the motor and the power conversion equipment.

The output voltage of an adjustable-speed drive, such as a variable-frequency drive (VFD), can be as much as 1.6 times the input voltage (e.g., a 120V input circuit for a VFD can result in 192V on the output circuit). When used with a variable speed motor, this is not concerning, as the motor is designed for this application. But what if a GFCI device is installed downstream of a VFD? A GFCI is not designed for that kind of increased voltage. This means the GFCI could be a fire or electric shock hazard. Due to this, the GFCI or SPGFCI must never be installed on the load side of a VFD.

Section 440.15, Split-System Disconnect Identification

New marking requirements were added for split-system HVAC installations.

As indicated in Sec. 440.8, a split-system HVAC setup is considered a single machine as it relates to the disconnecting means, so only one disconnect is required for the multiple components of the installation. That disconnecting means is typically located outdoors to satisfy Sec. 440.14. However, if there are multiple split-systems installed in the same building, an electrician or HVAC technician may need to work on the inside portion of the installation, and they need to know which disconnecting means controls the equipment they are going to service. This is already required by Sec. 110.22(A) but is often overlooked (Photo 4).

Section 495.2 Listing Requirements

New listing requirements were added for equipment exceeding 1,000V.

Few would argue against the need for listed equipment, especially equipment like medium-voltage switchgear, but most equipment used at these voltage levels is not listed. Why? Because there was no requirement for it. A manufacturer is not likely going to go through the expense of having their product listed if their competitor does not do it as well. Product safety standards for these types of equipment do exist, and getting listed equipment is currently possible.

However, manufacturers that have not had their equipment listed need time to do so. Additionally, suppliers and contractors need time to use up their existing inventory, hence the future effective dates for these requirements. The delayed enforcement dates give the industry time to transition without immediately making otherwise serviceable inventory unusable.