A 1/2-inch EMT nipple under 24 inches long carries four 12 AWG THHN conductors. What is the fill percentage, and does it comply?
Not quite. The answer is B: 17.5% — complies with the 60% nipple fill limit
Four 12 AWG THHN conductors occupy 4 × 0.0133 = 0.0532 sq in inside a 1/2-inch EMT's 0.304 sq in total area, or 17.5% fill. Because this run is a nipple under 24 inches, Chapter 9's 60% nipple allowance applies instead of the usual 40% cap for three or more conductors — a distinction people miss when they default to the general fill table without checking run length.
Reference: NEC 2023 Chapter 9, Table 1, Note 4 (Conduit Nipple Fill Exception)
Checked against multiple published sources
Two independent secondary sources agree on the requirement; neither is the code text. The 24-inch nipple allowance is Note 4 to Chapter 9, Table 1. One source is an older article that names no edition.
Trade Code Wizard is not affiliated with, endorsed by, or licensed by the International Code Council (ICC), the National Fire Protection Association (NFPA), IAPMO, the ESCO Institute, NATE, HVAC Excellence, NASCLA, NICET, the U.S. Environmental Protection Agency, PSI, Prov, Pearson VUE, or any state or local licensing board. Exam and code names are used only to identify which examination this study material prepares you for.
These are original practice questions written to publicly published exam content outlines. They are not actual exam questions, and they do not reproduce code text. Explanations cite code sections and state requirements in our own words — always verify against the code edition your jurisdiction has adopted, which may differ from the edition cited here.
Passing is not guaranteed. This is study material, not a substitute for the adopted code, for your licensing board's requirements, or for qualified instruction.