Checked against primary sources 2026-08-24
What is new in Article 430 this cycle
The motor sizing method is unchanged. One section is new, it is a flat prohibition rather than a calculation, and it is already in the printed book.
On this page
The one new section, and where it came from
A ground-fault circuit interrupter, or a special purpose ground-fault circuit interrupter, shall not be installed between the output terminals of power conversion equipment and the motor (NEC 430.132).
That is the whole section. It is a prohibition about a location, not a calculation, and it applies to the run between a drive output and the machine it turns.
It reached the book by tentative interim amendment. NFPA issued TIA 26-3 against the 2026 edition on 20 August 2025 with an effective date of 9 September 2025, and the amendment sheet records that the text was approved for incorporation into the document before printing.
So there is nothing to chase here. If you are holding a 2026 code book, 430.132 is printed in it. Checking the current amendment list for NFPA 70 is still worth doing before you rely on any section for real work, but you will not find this one waiting there.
Texas adopts the 2026 edition on September 1, 2026 under 16 TAC 73.100, which is the date the section starts deciding inspections here.
The method that did not change, and still catches people
Article 430 continues to use two different currents for two different jobs, and this is where most motor errors start (NEC 430.6).
- The table full-load current sizes conductors, switches, and short-circuit and ground-fault protection.
- The nameplate full-load amperes sizes overload protection, and nothing else in the common calculation.
They are usually close and almost never equal. Protecting the motor means nameplate. Protecting the wire means table.
The reason is not arbitrary. Overload protection is watching one specific motor, so it reads that motor. Short-circuit protection has to survive inrush, which is a property of the motor class, so the code standardizes it with a table.
Where the rounding rule reverses
On a general conductor, rounding the protective device up to the next standard size is permitted only when three conditions are met, one of which caps the selected rating at 800 amperes (NEC 240.4(B)).
On a motor branch circuit, rounding up is the expected path. The percentage from the branch-device table rarely lands on a standard rating and the code anticipates taking the next one (NEC 430.52).
Two rules that both say next higher standard size, pointing in different directions, used in the same problem. Knowing which article you are standing in is the whole thing.
The group rule that gets over-applied
For a feeder serving several motors, only one motor gets the 125 percent (NEC 430.24).
The sum has four parts. The highest rated motor is taken at 125 percent. Every other motor in the group is taken at its full-load current with no uplift. The non-motor load is added at its full value if it is noncontinuous, and at 125 percent if it is continuous.
Applying 125 percent to every motor produces a conductor that is oversized and a number that is wrong. The margin exists to cover one motor starting while the rest run, not all of them starting together.
Highest rated is settled by the section itself, which points at 430.6(A)(1) for the figure. That is the table current, so the largest motor in the group is the one with the largest table current, not the largest horsepower. On a mixed single-phase and three-phase group those can be different motors.
Reading Article 430 without getting lost
Article 430 is long and organized into parts by function rather than by workflow, which is why it reads badly front to back.
Figure 430.1 at the front of the article maps which part answers which question. It is the fastest navigation aid in the code and most people never open it.
Tab that figure rather than the start of the article. It will save more time than any other single tab in the book.
What this page cites
- NEC 430.132 New section, added to the 2026 edition by TIA 26-3, issued 20 August 2025 and effective 9 September 2025. The amendment sheet records that the text was incorporated before the edition was printed. source
- NEC 430.6 Which current applies to which calculation.
- NEC 430.24 Several motors on one feeder, and the four quantities the ampacity is built from.
- NEC 430.52 Branch-circuit short-circuit and ground-fault protection.
- NEC 240.4(B) The general next-higher rule, for contrast, and its 800 ampere ceiling.
- 16 TAC 73.100 Texas adoption of the 2026 National Electrical Code, effective September 1, 2026. source