2026 NEC Change to 250.122: What Electricians Need to Know About EGC Sizing

A Big Reorganisation of 250.122 for 2026

Section 250.122 — the rule that tells you how to size an equipment grounding conductor (EGC) — got a substantial rewrite in the 2026 edition of the NEC. The intent from Code-Making Panel 5 was to simplify the language and make the rules easier to apply. Whether they fully succeeded is debatable, but the result is now published, and every electrician working under the 2026 code needs to know what’s different.

This article walks through the structure of the new 250.122, with particular focus on the changes to parallel conductor sizing in 250.122(H), which is where the most consequential shift happens.

The General Rule and Table 250.122

The foundation hasn’t changed. The opening text now reads:

“Copper, aluminum, or copper-clad aluminum equipment grounding conductors of the wire type shall not be smaller than shown in Table 250.122 unless otherwise permitted by 250.122(A) through 250.122(I).”

That table is your starting point. You enter with the rating of the overcurrent protective device, and you read out the minimum EGC size:

• 60-amp OCPD → 10 AWG copper / 8 AWG aluminium
• 100-amp OCPD → 8 AWG copper / 6 AWG aluminium
• 200-amp OCPD → 6 AWG copper / 4 AWG aluminium

One reminder that’s worth repeating: if your OCPD doesn’t appear on the table, you round up. A 70-amp or 80-amp breaker uses the 100-amp row. A 150-amp breaker uses the 200-amp row. The gap above each listed rating belongs to the next row up.

250.122(A) — Never Larger Than the Circuit Conductor

The new (A) is short and direct: an EGC is not required to be larger than the circuit conductor supplying the equipment. The old language used the plural “circuit conductors,” which led to years of debate about whether, in a parallel installation, the EGC could legally be larger than any single ungrounded conductor (since all the paralleled A-phase conductors together formed “the circuit conductor”). The 2026 text leans toward the singular reading — though as we’ll see, that intent is muddier in 250.122(H) than it should be.

250.122(D) — Increased Conductor Size

If you upsize ungrounded conductors for any reason other than the adjustment and correction factors in 310.15(B) or (C), you must upsize the EGC proportionally to the increase in circular mil area.

The classic trigger here is voltage drop. Voltage drop isn’t a code mandate for general circuits — it’s good engineering practice, and it’s only required for things like sensitive electronic equipment and fire pumps. But the moment you bump conductors up from, say, 250 kcmil to 500 kcmil because of a long run, your EGC has to grow in the same ratio.

There’s an exception for qualified persons who can document an effective ground-fault current path under 250.4(A)(5) or 250.4(B)(4). In practice, most electricians won’t take that risk — if you upsized the ungrounded conductors, upsize the EGC.

A subtle gotcha: when you’re using a pre-made cable assembly like MC or tray cable, the manufacturer’s EGC is locked in by the cable’s UL listing. Bumping the cable up one trade size doesn’t guarantee the EGC will be proportionally larger. Be cautious here.

250.122(E) — Multiple Circuits in One Raceway

When several circuits share a single raceway, cable, trench, or cable tray, a single EGC can serve them all — provided it’s sized from Table 250.122 based on the largest overcurrent device feeding those circuits.

So if a raceway carries a 150-amp, a 100-amp, and an 80-amp circuit, the single shared EGC must be sized for the 150-amp device. Once those circuits split at a junction box, each branch can then drop down to its own properly sized EGC.

250.122(F) — Motor Circuits

Motor circuit EGCs follow either (F)(1) or (F)(2):

• (F)(1) — General: Size the EGC from Table 250.122 based on the rating of the branch-circuit short-circuit and ground-fault protective device (430.52). Remember, the overcurrent protection for a motor branch circuit doesn’t include overload — that’s handled separately by overload relays.
• (F)(2) — Instantaneous-trip breakers or motor short-circuit protectors: Use the maximum permitted rating of a dual-element time-delay fuse from 430.52(C)(1)(a) as your reference, then look up that value in Table 250.122.

The trick with (F)(2) is to mentally swap your instantaneous-trip breaker for the equivalent time-delay fuse, find the table value, and use that.

250.122(H) — The Big One: Conductors in Parallel

This is where the 2026 changes have the most real-world impact. (H) is now split into two parts.

(H)(1) — Parallel Conductors in a Single Raceway

When parallel conductors share one raceway, auxiliary gutter, or cable tray, a single wire-type EGC sized in accordance with 250.122 based on the OCPD for the feeder or branch circuit is permitted. Note that it points back to “250.122” in general — not specifically to the table — which leaves room for interpretation when you combine it with 250.122(A).

(H)(2) — Parallel Conductors in Multiple Raceways

When parallel circuit conductors are installed in two or more raceways:

1. A wire-type EGC must be installed in each raceway, sized per 250.122 based on the OCPD.
2. The EGC in each raceway is not required to be larger than the largest ungrounded conductor in that raceway.

That second item is the headline change. If you’re running, say, three 1/0 ungrounded conductors per phase across multiple raceways to feed a 4,000-amp piece of equipment, the EGC in each raceway never needs to be larger than 1/0 — regardless of what the table would otherwise dictate based on the OCPD.

(H)(1)(c) — Wire-Type EGCs in Cable Trays

Wire-type EGCs installed in cable trays must meet 392.10(B)(1)(c), which means they can be insulated, covered, or bare, but cannot be smaller than 4 AWG.

250.122 for Multiconductor Cables and Feeder Taps

A few more rules round out the section:

• Multiconductor cables in parallel: When you parallel multiconductor cables (MC, AC, TC, SE, NM), each cable’s internal EGC is usually undersized for the parallel application. The fix in 250.122(H)(2)(c) lets you run a single, properly-sized supplemental EGC alongside the cables in the raceway, gutter, trench, or tray — landed on the same bus at each end as the internal EGCs. That word “trench” was added for the 2026 cycle to close a small but real gap in the previous language.
• Sectioned EGCs (250.122(C)): Some multiconductor cables (often used for variable-frequency drives) divide the EGC across multiple internal conductors. As long as the combined circular mil area equals what Table 250.122 requires, it’s permitted.
• Feeder taps (250.122(I)): Size the EGC based on the OCPD ahead of the feeder on the supply side, but it never needs to be larger than the tap conductors themselves. If you tap with 6 AWG conductors, your EGC tops out at 6 AWG even if the upstream feeder OCPD would have called for larger.

The Bottom Line

The 2026 rewrite of 250.122 is genuinely an attempt to simplify, but the parallel rules in (H) introduce a meaningful change you need to internalise:

• In multiple-raceway parallel installations, the EGC in each raceway never has to exceed the largest ungrounded conductor in that raceway — full stop.
• In single-raceway parallel installations, the language sends you back to the table via the OCPD, but the interaction with 250.122(A) leaves room for interpretation.
• The general rule for upsizing EGCs proportionally when ungrounded conductors grow for voltage drop is unchanged.
• Motor, multiconductor cable, and feeder tap rules carry over with mostly cosmetic edits.

Whether you agreed with these changes during the public input cycle or not, they’re now the published rule. Install accordingly.

How NEC Mastery Fits Into This

Code changes like the rewrite of 250.122 are exactly the kind of thing that quietly trips up experienced electricians on exam day — the rule you’ve practised under for years has been reorganised, and the table reference you’re used to now lives in a different subsection. That’s where NEC Mastery earns its keep.

• 8,000+ exam-style questions updated to track the 2026 edition give you the repetition you need to reflex the new structure of 250.122 — including parallel sizing, motor circuits, and feeder taps
• Detailed explanations referencing specific NEC articles, sections, and tables mean every answer reinforces where the rule lives, not just what it says — so you can find it again under exam pressure
• Timed mock exams weighted to your exam type let you practise navigating the new 250.122(H) parallel rules under the clock, so the reorganisation works in your favour instead of against you
• No expensive prep course required — pair NEC Mastery directly with your 2026 NEC and build the structural familiarity that makes grounding and bonding questions feel routine