2026 NEC 250.122(F) Change: New Rules for Equipment Grounding Conductors in Parallel Raceways
250.122(F) in the 2026 NEC: Smarter EGC Sizing or a Step Away from Proven Protection?
One of the most discussed revisions in the 2026 NEC involves parallel raceways and the sizing of the equipment grounding conductor. While the new language offers a more practical outcome in the field, it also raises an important question: are we moving away from the long-standing conservative design philosophy that made Table 250.122 so dependable for decades?
For years, electricians, engineers, and inspectors have relied on Table 250.122 with very little controversy. Its concept was straightforward: size the equipment grounding conductor based on the rating or setting of the overcurrent protective device ahead of the circuit. That approach has been with us for decades, and although it sometimes produced results that seemed larger than expected, it carried with it a conservative level of confidence that the equipment grounding conductor would perform when fault conditions demanded it.
In the 2026 NEC, however, a notable revision to 250.122(F) changes the conversation for parallel installations. The new language now allows the equipment grounding conductor in each raceway or cable to be sized so that it is not required to be larger than the largest ungrounded conductor in that raceway or cable. From a practical standpoint, that change will be welcomed by many in the industry. From a design philosophy standpoint, it deserves a deeper discussion.
It is important to note that in many installations, certain raceways themselves may qualify as an effective equipment grounding conductor in accordance with the NEC. This discussion, however, is focused specifically on scenarios where a wire-type equipment grounding conductor is installed in parallel raceways or cables. The analysis presented here addresses the sizing considerations of that conductor under the revised language of 250.122(F) in the 2026 NEC.
🔍 What the 2023 NEC Required
Under the 2023 NEC, parallel raceways or cables containing conductors had to include an equipment grounding conductor in each raceway or cable. That was not the controversial part. The important detail was that the equipment grounding conductor in each raceway was sized in accordance with Table 250.122 based on the rating or setting of the overcurrent protective device protecting the overall circuit.
Because the sizing method was tied to the full overcurrent device, it was entirely possible for the equipment grounding conductor in each parallel raceway to be quite large, and in some cases to appear oversized when compared to the phase conductors installed in that same raceway.
Many in the field saw that as excessive. But from a pure protection standpoint, the logic was easy to defend. Table 250.122 was tied to the overcurrent device because the purpose of the equipment grounding conductor is to provide an effective ground-fault current path capable of facilitating the operation of the overcurrent protective device. The sizing was not historically tied to what simply looked proportionate in the raceway. It was tied to fault-clearing performance.
🛠️ What Changed in the 2026 NEC
The 2026 revision to 250.122(F) introduces an important limitation for parallel installations. While an equipment grounding conductor is still required in each raceway or cable, the new language now makes clear that the equipment grounding conductor in each individual raceway or cable is not required to be larger than the largest ungrounded conductor in that raceway or cable.
🟠 2023 NEC Approach
- Each parallel raceway or cable needed an equipment grounding conductor.
- The equipment grounding conductor in each raceway was sized from Table 250.122.
- The sizing was based on the overcurrent device protecting the full circuit.
- This could result in an equipment grounding conductor that was larger than the ungrounded conductors in that raceway.
🟢 2026 NEC Approach
- Each parallel raceway or cable still needs an equipment grounding conductor.
- Table 250.122 remains part of the discussion.
- However, the equipment grounding conductor in each raceway is now capped so it is not larger than the largest ungrounded conductor in that raceway or cable.
- The result is a more practical and often smaller equipment grounding conductor in parallel installations.
⚙️ Why Many Will Like This Change
Installers have long questioned situations where the equipment grounding conductor in a parallel raceway looked disproportionately large when compared with the phase conductors in that same raceway. The 2026 language addresses that concern directly.
On larger feeders and services installed in parallel raceways, copper adds up quickly. Any revision that eliminates what many view as excess conductor sizing will be seen as a cost-saving and labor-friendly improvement.
For many users of the Code, the new rule feels more intuitive. The idea that the equipment grounding conductor in a raceway should not exceed the largest ungrounded conductor in that raceway seems reasonable on its face, especially from an installation standpoint.
⚠️ Why This Change Still Deserves Healthy Debate
As someone involved in the code process, I can say plainly that the prior language was not some accidental oversight. The old approach existed because Table 250.122 has always been tied to overcurrent device performance. It has a long history behind it. The concern now is not whether the new rule is easier to install. The concern is whether it will always perform as reliably under severe fault conditions, especially where large overcurrent devices are involved.
The traditional concept behind Table 250.122 was simple: the equipment grounding conductor had to be sufficiently sized to carry fault current long enough to facilitate the operation of the protective device. That philosophy was conservative, but it was proven and understandable.
The issue with the 2026 revision is that it necessarily leans more heavily on the assumption that fault current in parallel paths will divide in a manner that still allows a smaller equipment grounding conductor in each raceway to do the job effectively. In theory, that may be entirely acceptable. In actual installations, however, theory and reality do not always align perfectly.
🚧 The Real-World Concern: Fault Current Does Not Always Behave Ideally
Parallel paths are often discussed as though current division will occur neatly and evenly. But the field teaches us otherwise. Small differences in conductor length, raceway geometry, termination quality, impedance, and installation conditions can influence how current divides during fault events.
- A fault may occur in one raceway and not across all raceways uniformly.
- The return path may not divide equally among the available parallel equipment grounding conductors.
- The overcurrent protective device still responds to the total current seen under the fault condition.
- The reduced size now permitted in each raceway may prove adequate, but the industry has less conservatism built into the rule than before.
That is why many experienced professionals are watching this change with interest. The revised language may be entirely workable, but it is fair to ask whether the new minimum will always provide the same dependable fault-clearing performance that the older, more conservative approach offered.
Example of the concern in plain language
Imagine a large feeder protected by a substantial overcurrent device and installed in parallel raceways. Under the earlier rule, the equipment grounding conductor in each raceway was sized from Table 250.122 based on that protective device. Under the new rule, the conductor in each raceway may now be limited by the size of the largest ungrounded conductor in that raceway.
The practical result is obvious: a smaller grounding conductor may now be installed in each raceway. The unanswered long-term question is equally obvious: if a severe fault occurs under less-than-ideal current-sharing conditions, will that reduced grounding conductor size always facilitate prompt operation of the large protective device with the same margin of confidence as before?
📚 Why This Is More Than Just a Sizing Detail
It would be easy to treat this revision as a simple cleanup item, but that would miss the larger point. This is not just about conductor proportions in a raceway. This is about whether the Code is subtly shifting from a historically conservative protection model toward a more optimized installation model.
That does not automatically make the change wrong. The NEC evolves, and not every long-standing rule should remain untouched forever. But where fault-clearing performance is concerned, the electrical industry has traditionally been cautious for good reason. Once the Code allows a reduction in grounding conductor size, the practical benefits are immediate. The long-term proof, however, will come only from experience in the field.
🧾 A Balanced Take on 250.122(F) in the 2026 NEC
- The 2026 revision is more practical for parallel raceway installations.
- It resolves the optics and cost concerns of having an equipment grounding conductor that may exceed the size of the largest ungrounded conductor in a raceway.
- It will likely be welcomed by installers, designers, and owners looking for efficiency.
- At the same time, it departs from a decades-old conservative relationship between equipment grounding conductor sizing and overcurrent device performance.
- The industry will now have to see whether the reduced sizing method proves equally dependable under real-world fault conditions involving large overcurrent devices.
🔚 Final Thought
The revision to 250.122(F) in the 2026 NEC is undeniably significant. It offers a more practical path for parallel installations and addresses a field concern that many have raised for years. But practicality and proven performance are not always the same thing.
Table 250.122 has stood the test of time because it was conservative and tied directly to the protective device that ultimately must clear the fault. The 2026 change introduces a more refined approach, but also a less conservative one. Whether that refinement proves just as reliable under high-level fault conditions is something the industry will answer over time, not in theory, but in the field.
That is what makes this code change worth watching.
📌 Authors Final Thoughts
The 2026 NEC revision to 250.122(F) changes how equipment grounding conductors are addressed in parallel raceways. While the new language brings practical relief by preventing the EGC from being larger than the largest ungrounded conductor in each raceway, it also raises an important industry question: will this reduced sizing method prove just as dependable in clearing large overcurrent devices during real-world fault conditions?
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1 Comment
great read, thanks paul.