MIL-HDBK-1004/10
Table 11
M Factors for Determining Economic Wire Size
(Cost of losses in 100 feet of copper cable at 1 cent per kW
CURRENT (amps)
CABLE
SIZE
10
20
30
40
50
60
70
80
10
0.893
3.57
8.04
8
0.561
2.25
5.05
9.00
14.00
6
0.360
1.44
3.24
5.76
9.00
13.00
17.64
4
0.226
0.905
2.03
3.62
5.65
8.14
11.08
14.46
2
0.1424
0.570
1.08
2.28
3.56
5.13
6.98
9.11
1
0.113
0.451
1.02
1.81
2.82
4.06
5.54
7.24
1/0
0.0893
0.357
0.804
1.425
2.23
3.21
4.47
5.71
2/0
0.0710
0.284
0.639
1.135
1.77
2.56
3.48
4.55
3/0
0.0562
0.257
0.506
0.900
1.40
2.03
2.76
3.60
4/0
0.0446
0.178
0.401
0.715
1.115
1.61
2.19
2.86
250 MCM 0.0378
0.151
0.340
0.605
0.945
1.36
1.85
2.42
300
0.0316
0.1265 0.284
0.506
0.790
1.14
1.55
2.02
350
0.0270
0.108
0.243
0.432
0.675
0.972
1.32
1.73
400
0.0237
0.0948 0.213
0.379
0.593
0.854
1.16
1.52
450
0.0210
0.0840 0.189
0.336
0.525
0.755
1.03
1.342
500
0.0189
0.0755 0.170
0.302
0.472
0.680
0.925
1.21
550
0.0172
0.0689 0.155
0.275
0.430
0.619
0.842
1.10
600
0.0158
0.0632 0.142
0.253
0.395
0.569
0.775
1.01
650
0.0145
0.0580 0.1305 0.232
0.362
0.522
0.710
0.928
700
0.0135
0.0540 0.1215 0.216
0.338
0.486
0.661
0.865
750
0.0126
0.0504 0.1132 0.202
0.315
0.454
0.616
0.805
1000
0.00945 0.0378 0.0970 0.151
0.236
0.340
0.463
0.605
connections and thermo-weld connections are used in the installation of
cathodic protection systems. Mechanical connections are less expensive t
thermo-weld connections but often have higher resistance and are more
susceptible to corrosion and mechanical damage. All connections must be
carefully insulated, particularly in the anode-to-power supply portion of
the circuit where any loss of insulation integrity will result in rapid
system failure. All connections in the power source to anode bed portion
the circuit and all cable-to-cable connections should be insulated by
encapsulation in epoxy using commercially available kits made expressly f
this purpose. The cable-to-structure connection is less critical and eit
epoxy encapsulation or insulation with hot coal-tar enamel followed by
wrapping with pipeline felt may be used on this connection. The followin
connections are required for impressed current systems:
a)
Connection between power source and structure
b)
Connection between anode bed(s) and power source (anode head
cable)
95
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