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NEC 2026 Changes: What's New for Wire Sizing
NEC 2026 (NFPA 70-2026) was published September 2025. Core ampacity values in Table 310.16 are unchanged. If you sized wire correctly under NEC 2023, the same sizing applies under NEC 2026.
PublishedSep 2025
Table 310.16Unchanged
Most statesStill NEC 2023
What changed in Article 310
Topic
NEC 2023
NEC 2026
Impact
Table 310.16 ampacity values
Current values
Identical
No change
Temperature correction
310.15(B)(1)(1)
Same section
No change
Bundling adjustment
310.15(C)(1)
Same section
No change
Termination limits
110.14(C)
110.14(C)
No change
Minimum conductor size
14 AWG copper min
16 AWG copper allowed
New
CCA conductors
Not listed
14 AWG CCA added (75C: 15A, 90C: 20A)
New
All WireRef ampacity tables and the ampacity calculator produce NEC 2026-valid results because Table 310.16 data is identical between editions.
Why 16 AWG is now allowed
NEC 2026 Section 310.5(A) lowers the minimum conductor size from 14 AWG to 16 AWG copper. This change addresses a practical gap: many HVAC control circuits, thermostat wiring, and equipment whips already use 16 AWG conductors per the manufacturer’s listing, but the NEC previously had no ampacity entry for them. The 2026 edition adds Table 310.16 values for 16 AWG copper: 10A at 60°C, 13A at 75°C, 18A at 90°C, with a maximum OCPD of 10A per 240.4(D).
This does not mean you should downsize branch circuits from 14 to 16 AWG. Standard 15A and 20A branch circuits still require 14 AWG or 12 AWG minimum. The 16 AWG allowance is primarily for control, signaling, and equipment circuits where the connected load is under 10A.
GFCI and AFCI updates
NEC 2023 was the big expansion cycle for GFCI (kitchens, basements, laundry). NEC 2026 adds refinements:
NewHigh-frequency GFCI
210.8 Informational Note now recognizes devices marked “HF” or “HF+” for VFD and inverter environments. Reduces nuisance tripping from high-frequency leakage.
ChangedEV charging (Art. 625)
GFCI trip threshold tightened to 5mA for EV circuits. Emergency shutoffs required for commercial/public EVSE. See EV charger guide.
Mandated on wider range of equipment, aligned with NFPA 70E-2024.
NewSurge protection
Dormitories and fire stations now require surge protection in sleeping areas.
ExpandedEnergy storage (Art. 706)
Significantly expanded for residential battery installations (Tesla Powerwall, Enphase IQ, etc.). New requirements for disconnect labeling, ventilation, and fire safety clearances.
ReorganizedCommunications (Ch. 8)
Chapters 1–4 now apply to communications installations. This integrates fire alarm, data, and low-voltage systems into the main NEC framework.
MovedLoad calculations (Art. 220 to 120)
Dwelling unit load calculations relocated from Article 220 to new Article 120. Methodology is unchanged but section numbers differ.
NewNon-road EVs (Art. 624)
New article covers electric vehicle equipment for boats, forklifts, golf carts, and other non-road vehicles. Separate from Art. 625 road vehicles.
State adoption status
NEC adoption varies by state. Most jurisdictions currently enforce NEC 2020 or NEC 2023. Adoption of NEC 2026 is expected to begin in 2026–2027 with early-adopter states. Always verify which edition your local AHJ enforces before starting electrical work.
Status
Typical states
WireRef data
NEC 2023
Majority of states (current cycle)
All values current ✓
NEC 2020
Some states still on prior cycle
Ampacity identical ✓
NEC 2026
No states adopted yet
Ampacity identical ✓
What this means for WireRef
Nothing changes for you right now. All ampacity values, derating factors, and termination limits on WireRef are valid under NEC 2023 and NEC 2026. WireRef will update section number references when NEC 2026 becomes the dominant adopted edition.
Requirements vary by state. NEC edition, licensing, permits, and GFCI rules differ by jurisdiction. Check your state or pick it below for personalized info across WireRef.