Page 87 - IS-Rayfast Catalogue - Issue 9, 2017
P. 87

Wire and Cable
                                                      Custom Cable Designs
                                                               Technical Information
                                                              Multi-conductor cables

       Wire Bundle Multiplication Factors       Number of Wires  Multiplication Factor  1
       Equal Size Wires
                                                      1               1.00
       The table right provides multiplication factors
       for wire bundles of 1 to 61. To determine the   2              2.00        2
       approximate diameter of a wire bundle when
                                                      3               2.16
       the wires are all the same size, find the factor
                                                      4               2.41        3
       for the number of wires in the bundle and
       multiply the wire diameter by that factor.     5               2.70
                                                     6, 7             3.00        4
       Calculation of Wire Bundle
                                                      8               3.60
       Different Size Wires
                                                  9, 10, 11, 12       4.00
       To determine the wire bundle diameter when                                 5
       using wires of different sizes, follow steps:  13, 14          4.41
        1.  Determine the number of wires in the wire   15, 16        4.70        6
          bundle.
                                                   17, 18, 19         5.00
        2.  Find the diameter of the wires in the Wire
          and Cable section of this catalogue.      20, 21            5.31        7
        3.  Calculate the cable bundle outside     22, 23, 24         5.61
          diameter by using the example below.
                                                   25, 26, 27         6.00
                                                                                  8
                                                   28, 29, 30         6.41
       Example: A bundle of wires containing:
       •   3 wires of 44A0111-22 (@ 1.19mm dia.)   31, 32, 33         6.70
       •   5 wires of 44A0111-20 (@ 1.40mm dia.)  34, 35, 36, 37      7.00        9
       •   1 wire of 44A0111-18 (@ 1.65mm dia.)
                                                   38, 39 40          7.31
                                                                                 10
                                                  41, 42, 43, 44      7.61
       D = 1.2 √ (3 x 1.19  + 5 x 1.40  + 1 x 1.65 )
                    2
                                     2
                             2
       D = 1.2 √ (3 x 1.42 + 5 x 1.96 + 1 x 2.72)  45, 46, 47, 48     8.00
       D = 1.2 √ (4.26 + 9.80 + 2.72)             49, 50, 51, 52      8.41       11
       D = 1.2 √ (16.78)
                                                  53, 54, 55, 56      8.70
       D = 1.2 x 4.10
       D = 4.92mm                                57, 58, 59, 60, 61   9.00       12
                                                                                 13
       Resistance and Current Carrying Capacity
       Conductor Size (AWG) Tinned Cu  30  28  26  24  22  20   18  16   14  12  14
       Max Resistance Ohms/km @ 20ºC  356  225  135  86.0  53.2  32.4  20.4  15.8  9.9  6.6
                                                                                 15
       Current Carrying Capacity (amps)   2.2  2.9  4.1  5.5  7.4  10.  14.0  15.5  21.0  28.0
       Current carrying capacity for 30ºC rise above 20ºC ambient
                                                                                 16
       Current Carrying Capacity Multiplying Factor for multicore cables of the same size
                                                                                 17
       Number of Cores  2   3   4    7    9   12  15   18  21   24  27   30  37
                                                                                 18
       Derating Factor  0.825 0.73  0.66  0.54  0.49  0.43  0.39  0.36  0.33  0.31  0.29  0.28  0.26


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