Components
Simplifying this formula results in the
formula used for wire ll calculation:
General Formula
Panduit Wiring Duct wire lls are calculated using the following general formula:
Why use a 50% Wire Fill?
As specied in NFPA79-2012 section 13.5.2, Percentage Fills of
Raceways (Ducts), a 50% wire ll is given as the maximum wire ll capacity in
all Panduit Wiring Ducts. This helps ensure general safe wiring practices are
followed. In actual practice, a 50% wire ll is the maximum amount of wiring
the duct can hold given the additional airspace created between cables by
non-uniform cable shapes, cable interlacing, and cable packing factors.
Wire Area
The wire area formula is converted
to allow calculation using the
cable diameter:
0
Formula Derivation
Inserting the elements from above into the
general formula results in the following:
Calculation of Internal Area
Air Space Allotment
What is the Usable Duct Area?
The usable area we dene as the calculation of
internal area that can be occupied by wires or
cables. Accounting for thickness of material, 90%
of the nominal area (WxH) is used in the formula.
Nominal Duct
Size
(W x H)
In.
Nominal
Area
In.²
Electrical Communication
8
AWG
10
AWG
12
AWG
14
AWG
16
AWG
18
AWG
22
AWG
23
AWG
23/24
AWG
24
AWG
Fiber
Cable
0.216 0.164 0.13 0.141 0.152 0.111 0.124 0.133 0.096 0.111 0.118 0.084 0.100 0.106 0.085 0.330 0.25 0.190 0.118
THHN THHN THHN MTW MTW THHN MTW MTW TFFN MTW MTW TFFN MTW MTW MTW
Cat.
6A
Cat.
6
Cat.
5e
3.0
mm
0.50 x 0.50 0.250 3 5 8 7 6 11 9 8 15 11 10 20 14 12 19 1 2 3 10
0.50 x 1.00 0.500 6 10 16 14 12 23 18 16 31 23 20 40 28 25 39 2 4 7 20
0.50 x 2.00 1.000 12 21 33 28 24 46 37 32 62 46 41 80 57 50 79 5 9 15 40
0.75 x 0.75 0.563 6 11 19 16 13 26 20 18 34 26 23 45 32 28 44 2 5 8 23
0.75 x 1.00 0.750 9 15 25 21 18 34 27 24 46 34 30 60 42 38 59 3 6 11 30
0.75 x 1.50 1.125 13 23 38 32 27 52 41 36 69 52 46 91 64 57 88 5 10 17 46
0.75 x 2.00 1.500 18 31 50 43 37 69 55 48 93 69 61 121 85 76 118 7 13 23 61
1.00 x 1.00 1.000 12 21 33 28 24 46 37 32 62 46 41 80 57 50 79 5 9 15 40
1.00 x 1.50 1.500 18 31 50 43 37 69 55 48 93 69 61 121 85 76 118 7 13 23 61
1.00 x 2.00 2.000 24 42 67 57 49 92 74 64 124 92 82 161 114 101 158 10 18 31 81
1.00 x 3.00 3.000 36 63 101 86 74 139 111 96 186 139 123 242 171 152 237 15 27 47 122
1.00 x 4.00 4.000 48 84 135 114 98 185 148 129 248 185 164 323 228 203 316 20 36 63 163
1.50 x 1.00 1.500 18 31 50 43 37 69 55 48 93 69 61 121 85 76 118 7 13 23 61
1.50 x 1.50 2.250 27 47 76 64 55 104 83 72 139 104 92 182 128 114 177 11 20 35 92
1.50 x 2.00 3.000 36 63 101 86 74 139 111 96 186 139 123 242 171 152 237 15 27 47 122
1.50 x 3.00 4.500 55 95 152 129 111 208 167 145 279 208
184 364 257 228 355 23 41 71 184
1.50 x 4.00 6.000 73 127 202 172 148 278 222 193 372 278 246 485 342 305 474 31 54 94 245
2.00 x 1.00 2.000 24 42 67 57 49 92 74 64 124 92 82 161 114 101 158 10 18 31 81
2.00 x 1.50 3.000 36 63 101 86 74 139 111 96 186 139 123 242 171 152 237 15 27 47 122
2.00 x 2.00 4.000 48 84 135 114 98 185 148 129 248 185 164 323 228 203 316 20 36 63 163
2.00 x 3.00 6.000 73 127 202 172 148 278 222 193 372 278 246 485 342 305 474 31 54 94 245
2.00 x 4.00 8.000 97 169 270 229 197 371 297 258 496 371 328 647 457 406 632 41 73 126 327
2.00 x 5.00 10.000 122 212 338 287 247 463 371 323 620 463 410 809 571 508 790 52 91 158 409
2.50 x 3.00 7.500 91 159 253 215 185 347 278 242 465 347 307 607 428 381 593 39 68 118 307
3.00 x 1.00 3.000 36 63 101 86 74 139 111 96 186 139 123 242 171 152 237 15 27 47 122
3.00 x 2.00 6.000 73 127 202 172 148 278 222 193 372 278 246 485 342 305 474 31 54 94 245
3.00 x 3.00 9.000 110 191 304 258 222 417 334 290 558 417 369 728 514 457 711 47 82 142 368
3.00 x 4.00 12.000 146 254 405 344 296 556 445 387 744 556 492 971 685 610 949 62 109 189 491
3.00 x 5.00 15.000 183 318 507 431 370 695 557 484 930 695 615 1214 857 762 1186 78 137 237 614
4.00 x 1.50 6.000 73 127 202 172 148 278 222 193 372 278 246 485 342 305 474 31 54 94 245
4.00 x 2.00 8.000 97 169 270 229 197 371 297 258 496 371 328 647 457 406 632 41 73 126 327
4.00 x 3.00 12.000 146 254 405 344 296 556 445 387 744 556 492 971 685 610 949 62 109 189 491
4.00 x 4.00 16.000 195 339 540 459 395 742 594 516 992 742 656 1295 914 813 1265 83 146 253 655
4.00 x 5.00 20.000 244 424 676 574 494 927 743 646 1240 927 820 1619 1142 1017 1581 104 182 316 819
6.00 x 4.00 24.000 293 509 811 689 593 1113 891 775 1488 1113 984
1943 1371 1220 1898 125 219 379 983
Panduct
®
Type D, G, F and FS Wiring Duct – Wire Fill Capacity
Note: When calculating wire ll capacity using the above formula, variables W, H, and D must be expressed in same units (i.e. mm or inches).
4