Table 4 - Dimensions and Percent Area of Conduit and Tubing

Oct 12, 2026

Uploaded by SANS

Table 4 presents dimensions and percent area calculations for electrical conduit and tubing types, aligned with allowable wire combinations referenced in Table 1 and Chapter 9. It lists metric designators and trade sizes with nominal internal diameters, then provides corresponding total internal area at 100% along with reduced percentages for 60%, 53%, 31%, and over-2-wires conditions. The table includes multiple conduit articles, including EMT, ENT, FMC, IMC, and LFNC-B, showing area values in both mm² and in.².

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Table 4 Dimensions and Percent Area of Conduit and Tubing

Article 358—Electrical Metallic Tubing (EMT)

Article 362—Electrical Nonmetallic Tubing (ENT)

Article 348—Flexible Metal Conduit (FMC)

Article 342—Intermediate Metal Conduit (IMC)

Article 356—Liquidtight Flexible Nonmetallic Conduit (LFNC-B*)

Table 4 Dimensions and Percent Area of Conduit and Tubing (Areas of Conduit or Tubing for the Combinations of Wires Permitted in Table 1, Chapter 9) | Article 358—Electrical Metallic Tubing (EMT) | | | | | | | | | | | | | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Metric
Designator | Trade
Size | Nominal
Internal
Diameter | | Total Area
100% | | 60% | | 1 Wire
53% | | 2 Wires
31% | | Over 2 Wires
40% | | | | | mm | in. | mm2 | in.2 | mm2 | in.2 | mm2 | in.2 | mm2 | in.2 | mm2 | in.2 | | 16 | 1⁄2 | 15.8 | 0.622 | 196 | 0.304 | 118 | 0.182 | 104 | 0.161 | 61 | 0.094 | 78 | 0.122 | | 21 | 3⁄4 | 20.9 | 0.824 | 343 | 0.533 | 206 | 0.320 | 182 | 0.283 | 106 | 0.165 | 137 | 0.213 | | 27 | 1 | 26.6 | 1.049 | 556 | 0.864 | 333 | 0.519 | 295 | 0.458 | 172 | 0.268 | 222 | 0.346 | | 35 | 11⁄4 | 35.1 | 1.380 | 968 | 1.496 | 581 | 0.897 | 513 | 0.793 | 300 | 0.464 | 387 | 0.598 | | 41 | 11⁄2 | 40.9 | 1.610 | 1314 | 2.036 | 788 | 1.221 | 696 | 1.079 | 407 | 0.631 | 526 | 0.814 | | 53 | 2 | 52.5 | 2.067 | 2165 | 3.356 | 1299 | 2.013 | 1147 | 1.778 | 671 | 1.040 | 866 | 1.342 | | 63 | 21⁄2 | 69.4 | 2.731 | 3783 | 5.858 | 2270 | 3.515 | 2005 | 3.105 | 1173 | 1.816 | 1513 | 2.343 | | 78 | 3 | 85.2 | 3.356 | 5701 | 8.846 | 3421 | 5.307 | 3022 | 4.688 | 1767 | 2.742 | 2280 | 3.538 | | 91 | 31⁄2 | 97.4 | 3.834 | 7451 | 11.545 | 4471 | 6.927 | 3949 | 6.119 | 2310 | 3.579 | 2980 | 4.618 | | 103 | 4 | 110.1 | 4.334 | 9521 | 14.753 | 5712 | 8.852 | 5046 | 7.819 | 2951 | 4.573 | 3808 | 5.901 | Article 362—Electrical Nonmetallic Tubing (ENT) Designator Designator | Metric | Trade
Size | Nominal
Internal
Diameter | | Total Area
100% | | 60% | | 1 Wire
53% | | 2 Wires
31% | | Over 2 Wires
40% | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | | mm | in. | mm2 | in.2 | mm2 | in.2 | mm2 | in.2 | mm2 | in.2 | mm2 | in.2 | | 16 | 1⁄2 | 14.2 | 0.560 | 158 | 0.246 | 95 | 0.148 | 84 | 0.131 | 49 | 0.076 | 63 | 0.099 | | 21 | 3⁄4 | 19.3 | 0.760 | 293 | 0.454 | 176 | 0.272 | 155 | 0.240 | 91 | 0.141 | 117 | 0.181 | | 27 | 1 | 25.4 | 1.000 | 507 | 0.785 | 304 | 0.471 | 269 | 0.416 | 157 | 0.243 | 203 | 0.314 | | 35 | 11⁄4 | 34.0 | 1.340 | 908 | 1.410 | 545 | 0.846 | 481 | 0.747 | 281 | 0.437 | 363 | 0.564 | | 41 | 11⁄2 | 39.9 | 1.570 | 1250 | 1.936 | 750 | 1.162 | 663 | 1.026 | 388 | 0.600 | 500 | 0.774 | | 53 | 2 | 51.3 | 2.020 | 2067 | 3.205 | 1240 | 1.923 | 1095 | 1.699 | 641 | 0.993 | 827 | 1.282 | | 63 | 21⁄2 | — | — | — | — | — | — | — | — | — | — | — | — | | 78 | 3 | — | — | — | — | — | — | — | — | — | — | — | — | | 91 | 31⁄2 | — | — | — | — | — | — | — | — | — | — | — | — | Article 348—Flexible Metal Conduit (FMC) | Metric | Trade
Size | Nominal
Internal
Diameter | | Total Area
100% | | 60% | | 1 Wire
53% | | 2 Wires
31% | | Over 2 Wires
40% | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | | | mm | in. | mm2 | in.2 | mm2 | in.2 | mm2 | in.2 | mm2 | in.2 | mm2 | in.2 | | 12 | 3⁄8 | 9.7 | 0.384 | 74 | 0.116 | 44 | 0.069 | 39 | 0.061 | 23 | 0.036 | 30 | 0.046 | | 16 | 1⁄2 | 16.1 | 0.635 | 204 | 0.317 | 122 | 0.190 | 108 | 0.168 | 63 | 0.098 | 81 | 0.127 | | 21 | 3⁄4 | 20.9 | 0.824 | 343 | 0.533 | 206 | 0.320 | 182 | 0.283 | 106 | 0.165 | 137 | 0.213 | | 27 | 1 | 25.9 | 1.020 | 527 | 0.817 | 316 | 0.490 | 279 | 0.433 | 163 | 0.253 | 211 | 0.327 | | 35 | 11⁄4 | 32.4 | 1.275 | 824 | 1.277 | 495 | 0.766 | 437 | 0.677 | 256 | 0.396 | 330 | 0.511 | | 41 | 11⁄2 | 39.1 | 1.538 | 1201 | 1.858 | 720 | 1.115 | 636 | 0.985 | 372 | 0.576 | 480 | 0.743 | | 53 | 2 | 51.8 | 2.040 | 2107 | 3.269 | 1264 | 1.961 | 1117 | 1.732 | 653 | 1.013 | 843 | 1.307 | | 63 | 21⁄2 | 63.5 | 2.500 | 3167 | 4.909 | 1900 | 2.945 | 1678 | 2.602 | 982 | 1.522 | 1267 | 1.963 | | 78 | 3 | 76.2 | 3.000 | 4560 | 7.069 | 2736 | 4.241 | 2417 | 3.746 | 1414

FAQs

What information does Table 4 provide for conduit and tubing?

It provides nominal internal diameters and internal area values for each conduit/tubing type, including total area at 100% and reduced percentages used for different wire fill scenarios.

Which percentage columns are included in the table?

The table includes total area at 100%, plus values for 60% and wire-related percentages such as 53%, 31%, and over 2 wires at 40%.

Which conduit article types are covered in this excerpt of Table 4?

The excerpt includes Article 358 (EMT), Article 362 (ENT), Article 348 (FMC), Article 342 (IMC), and Article 356 (LFNC-B*).

Oct 12, 2026

Uploaded by SANS