Practice question · NEC Table 430.52

What Size Breaker for a 22A Motor?

By Mason Garry, Master Electrician · October 15, 2026 · 2 min read

What size breaker for a 22A motor is a round-up question in disguise. You do the Table 430.52 math first, then you check whether that number is even a breaker you can buy. Here, it is not, and that second step decides the answer.

Answer: A) 60A. 22 × 2.5 = 55A, and where the calculation does not land on a standard rating, the next higher standard rating is permitted, so you go to 60A.

Where to Find It

Open your Code book to Table 430.52 and read it together with 430.52(C)(1) Exception 1. Table 430.52 gives the inverse-time breaker percentage used in the stem: 250% of the 22A full-load current. That is 22 × 2.5 = 55A. Exception 1 then handles the problem the stem names directly: 55A is not a standard rating, so the next higher standard rating per 240.6 is permitted, which is 60A.

Why 60 Amps

Step one is the multiplication, and the stem has already done it for you: 22A at 250% is 55A. If you stop there, you pick option B, 55A. That is exactly the trap. There is no standard 55A breaker in this question, because the stem tells you 55A is not a standard rating.

Step two is the rule in 430.52(C)(1) Exception 1. Where the calculated value does not correspond to a standard rating, you are permitted to use the next higher standard rating per 240.6. Next higher from 55A is 60A, option A. You do not round down to 50A, and you do not jump past the next standard rating to 70A.

Tab Table 430.52 plus "430.52(C)(1) Ex. 1" in your book with a short note: calculate first, then round up to standard. That note turns a two-step question into a fast lookup on test day.

The Trap

Option B, 55A, is the math-only answer. Option C, 50A, is rounding in the wrong direction. Option D, 70A, goes higher than the next standard rating the Exception permits. The question asks for the maximum permitted breaker, and the permitted move from 55A is one step up to 60A, nothing more and nothing less.

Exam Tip

When a motor protection stem tells you the calculated value "is not a standard rating," it is handing you the second step. Do not re-do the math and move on. Look for the next higher standard rating, check it against 240.6, and pick that. We drill this same pattern on the fuse side in the 22A fuse question.

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