# 392.22 Number of Conductors or Cables

**Table 392.22(A) Allowable Cable Fill Area for Multiconductor Cables in Ladder, Ventilated Trough, or Solid Bottom Cable Trays for Cables Rated 2000 Volts or Less**

Inside Width of Cable Tray | Maximum Allowable Fill Area for Multiconductor Cables | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|

Ladder or Ventilated Trough or Wire Mesh Cable Trays, 392.22(A)(1) | Solid Bottom Cable Trays, 392.22(A)(3) | ||||||||||

Column 1 Applicable for 392.22(A)(1)(b) Only | Column 2^{a} Applicable for 392.22(A)(1)(c) Only |
Column 3 Applicable for 392.22(A)(3)(b) Only | Column 4^{a} Applicable for 392.22(A)(3)(c) Only |
||||||||

mm | in. | mm^{2} |
in.^{2} |
mm^{2} |
in.^{2} |
mm^{2} |
in.^{2} |
mm^{2} |
in.^{2} |
||

50 | 2.0 | 1,500 | 2.5 | 1,500 — (30 Sd)^{b} |
2.5 — (1.2 Sd)^{b} |
1,200 | 2.0 | 1,200 — (25 Sd)^{b} |
2.0 — Sd^{b} |
||

100 | 4.0 | 3,000 | 4.5 | 3,000 — (30 Sd)^{b} |
4.5 — (1.2 Sd) | 2,300 | 3.5 | 2,300 — (25 Sd) | 3.5 — Sd | ||

150 | 6.0 | 4,500 | 7.0 | 4,500 — (30 Sd)^{b} |
7 — (1.2 Sd) | 3,500 | 5.5 | 3,500 — (25 Sd)^{b} |
5.5—Sd | ||

200 | 8.0 | 6,000 | 9.5 | 6,000 — (30 Sd)^{b} |
9.5 — (1.2 Sd) | 4,500 | 7.0 | 4,500 — (25 Sd) | 7.0 — Sd | ||

225 | 9.0 | 6,800 | 10.5 | 6,800 — (30 Sd) | 10.5 — (1.2 Sd) | 5,100 | 8.0 | 5,100 — (25 Sd) | 8.0 — Sd | ||

300 | 12.0 | 9,000 | 14.0 | 9,000 — (30 Sd) | 14 — (1.2 Sd) | 7,100 | 11.0 | 7,100 — (25 Sd) | 11.0 — Sd | ||

400 | 16.0 | 12,000 | 18.5 | 12,000 — (30 Sd) | 18.5 — (1.2 Sd) | 9,400 | 14.5 | 9,400 — (25 Sd) | 14.5 — Sd | ||

450 | 18.0 | 13,500 | 21.0 | 13,500 — (30 Sd) | 21 — (1.2 Sd) | 10,600 | 16.5 | 10,600 — (25 Sd) | 16.5 — Sd | ||

500 | 20.0 | 15,000 | 23.5 | 15,000 — (30 Sd) | 23.5 — (1.2 Sd) | 11,800 | 18.5 | 11,800 — (25 Sd) | 18.5 — Sd | ||

600 | 24.0 | 18,000 | 28.0 | 18,000 — (30 Sd) | 28 — (1.2 Sd) | 14,200 | 22.0 | 14,200 — (25 Sd) | 22.0 — Sd | ||

750 | 30.0 | 22,500 | 35.0 | 22,500 — (30 Sd) | 35 — (1.2 Sd) | 17,700 | 27.5 | 17,700 — (25 Sd) | 27.5 — Sd | ||

900 | 36.0 | 27,000 | 42.0 | 27,000 — (30 Sd) | 42 — (1.2 Sd) | 21,300 | 33.0 | 21,300 — (25 Sd) | 33.0 — Sd | ||

^{a}The maximum allowable fill areas in Columns 2 and 4 shall be calculated. For example, the maximum allowable fill in mm^{2} for a 150-mm wide cable tray in Column 2 shall be 4500 minus (30 multiplied by Sd) [the maximum allowable fill, in square inches, for a 6-in. wide cable tray in Column 2 shall be 7 minus (1.2 multiplied by Sd)]. |
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^{b}The term Sd in Columns 2 and 4 is equal to the sum of the diameters, in mm, of all cables 107.2 mm (in inches, of all 4/0 AWG) and larger multiconductor cables in the same cable tray with smaller cables. |

(a) Where all of the cables are 4/0 AWG or larger, the sum of the diameters of all cables shall not exceed the cable tray width, and the cables shall be installed in a single layer. Where the cable ampacity is determined according to 392.80(A)(1)(c), the cable tray width shall not be less than the sum of the diameters of the cables and the sum of the required spacing widths between the cables.

(b) Where all of the cables are smaller than 4/0 AWG, the sum of the cross-sectional areas of all cables shall not exceed the maximum allowable cable fill area in Column 1 of Table 392.22(A) for the appropriate cable tray width.

(c) Where 4/0 AWG or larger cables are installed in the same cable tray with cables smaller than 4/0 AWG, the sum of the cross-sectional areas of all cables smaller than 4/0 AWG shall not exceed the maximum allowable fill area resulting from the calculation in Column 2 of Table 392.22(A) for the appropriate cable tray width. The 4/0 AWG and larger cables shall be installed in a single layer, and no other cables shall be placed on them.

(a) Where all of the cables are 4/0 AWG or larger, the sum of the diameters of all cables shall not exceed 90 percent of the cable tray width, and the cables shall be installed in a single layer.

(b) Where all of the cables are smaller than 4/0 AWG, the sum of the cross-sectional areas of all cables shall not exceed the maximum allowable cable fill area in Column 3 of Table 392.22(A) for the appropriate cable tray width.

(c) Where 4/0 AWG or larger cables are installed in the same cable tray with cables smaller than 4/0 AWG, the sum of the cross-sectional areas of all cables smaller than 4/0 AWG shall not exceed the maximum allowable fill area resulting from the computation in Column 4 of Table 392.22(A) for the appropriate cable tray width. The 4/0 AWG and larger cables shall be installed in a single layer, and no other cables shall be placed on them.

(a) Where only one multiconductor cable is installed, the cross-sectional area shall not exceed the value specified in Column 1 of Table 392.22(A)(5).

(b) Where more than one multiconductor cable is installed, the sum of the cross-sectional area of all cables shall not exceed the value specified in Column 2 of Table 392.22(A)(5).

**Table 392.22(A)(5) Allowable Cable Fill Area for Multiconductor Cables in Ventilated Channel Cable Trays for Cables Rated 2000 Volts or Less**

Inside Width of Cable Tray | Maximum Allowable Fill Area for Multiconductor Cables | ||||
---|---|---|---|---|---|

Column 1 One Cable | Column 2 More Than One Cable | ||||

mm | in. | mm^{2} |
in.^{2} |
mm^{2} |
in.^{2} |

75 | 3 | 1500 | 2.3 | 850 | 1.3 |

100 | 4 | 2900 | 4.5 | 1600 | 2.5 |

150 | 6 | 4500 | 7.0 | 2450 | 3.8 |

(a) Where only one multiconductor cable is installed, the cross-sectional area of the cable shall not exceed the value specified in Column 1 of Table 392.22(A)(6).

(b) Where more than one multiconductor cable is installed, the sum of the cross-sectional area of all cable shall not exceed the value specified in Column 2 of Table 392.22(A)(6).

**Table 392.22(A)(6) Allowable Cable Fill Area for Multiconductor Cables in Solid Channel Cable Trays for Cables Rated 2000 Volts or Less**

Inside Width of Cable Tray | Column 1 One Cable | Column 2 More Than One Cable | |||||
---|---|---|---|---|---|---|---|

mm | in. | mm^{2} | in.^{2} | mm^{2} | in.^{2} | ||

50 | 2 | 850 | 1.3 | 500 | 0.8 | ||

75 | 3 | 1300 | 2.0 | 700 | 1.1 | ||

100 | 4 | 2400 | 3.7 | 1400 | 2.1 | ||

150 | 6 | 3600 | 5.5 | 2100 | 3.2 |

(a) Where all of the cables are 1000 kcmil or larger, the sum of the diameters of all single-conductor cables shall not exceed the cable tray width, and the cables shall be installed in a single layer. Conductors that are bound together to comprise each circuit group shall be permitted to be installed in other than a single layer.

(b) Where all of the cables are from 250 kcmil through 900 kcmil, the sum of the cross-sectional areas of all single-conductor cables shall not exceed the maximum allowable cable fill area in Column 1 of Table 392.22(B)(1) for the appropriate cable tray width.

(c) Where 1000 kcmil or larger single-conductor cables are installed in the same cable tray with single-conductor cables smaller than 1000 kcmil, the sum of the cross sectional areas of all cables smaller than 1000 kcmil shall not exceed the maximum allowable fill area resulting from the computation in Column 2 of Table 392.22(B)(1) for the appropriate cable tray width.

(d) Where any of the single conductor cables are 1/0 through 4/0 AWG, the sum of the diameters of all single conductor cables shall not exceed the cable tray width.

**Table 392.22(B)(1) Allowable Cable Fill Area for Single-Conductor Cables in Ladder, Ventilated Trough, or Wire Mesh Cable Trays for Cables Rated 2000 Volts or Less**

Inside Width of Cable Tray | Maximum Allowable Fill Area for Single-Conductor Cables in Ladder, Ventilated Trough, or Wire Mesh Cable Trays | ||||||||
---|---|---|---|---|---|---|---|---|---|

Column 1 Applicable for 392.22(B)(1)(b) Only | Column 2^{a} Applicable for 392.22(B)(1)(c) Only | ||||||||

mm | in. | mm^{2} | in.^{2} | mm^{2} | in.^{2} | ||||

50 | 2 | 1,400 | 2.0 | 1,400 — (28 Sd)^{b} | 2.0 — (1.1 Sd)^{b} | ||||

100 | 4 | 2,800 | 4.5 | 2,800 — (28 Sd) | 4.5 — (1.1 Sd) | ||||

150 | 6 | 4,200 | 6.5 | 4,200 — (28 Sd)^{b} | 6.5 — (1.1 Sd)^{b} | ||||

200 | 8 | 5,600 | 8.5 | 5,600 — (28 Sd) | 8.5 — (1.1 Sd) | ||||

225 | 9 | 6,100 | 9.5 | 6,100 — (28 Sd) | 9.5 — (1.1 Sd) | ||||

300 | 12 | 8,400 | 13.0 | 8,400 — (28 Sd) | 13.0 — (1.1 Sd) | ||||

400 | 16 | 11,200 | 17.5 | 11,200 — (28 Sd) | 17.5 — (1.1 Sd) | ||||

450 | 18 | 12,600 | 19.5 | 12,600 — (28 Sd) | 19.5 — (1.1 Sd) | ||||

500 | 20 | 14,000 | 21.5 | 14,000 — (28 Sd) | 21.5 — (1.1 Sd) | ||||

600 | 24 | 16,800 | 26.0 | 16,800 — (28 Sd) | 26.0 — (1.1 Sd) | ||||

750 | 30 | 21,000 | 32.5 | 21,000 — (28 Sd) | 32.5 — (1.1 Sd) | ||||

900 | 36 | 25,200 | 39.0 | 25,200 — (28 Sd) | 39.0 — (1.1 Sd) | ||||

^{a}The maximum allowable fill areas in Column 2 shall be calculated. For example, the maximum allowable fill, in mm^{2}, for a 150-mm wide cable tray in Column 2 shall be 4200 minus (28 multiplied by Sd) [the maximum allowable fill, in square inches, for a 6-in. wide cable tray in Column 2 shall be 6.5 minus (1.1 multiplied by Sd)]. | |||||||||

^{b}The term Sd in Column 2 is equal to the sum of the diameters, in mm, of all cables 507 mm^{2} (in inches, of all 1000 kcmil) and larger single-conductor cables in the same cable tray with small cables. |

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