Substation Design Data

BUS DESIGN
Bus Size (IPS) 1 1-1/2 2 2-1/2 3 3-1/2 4 5 6
Outside Diameter 1.315 1.9 2.375 2.875 3.5 4 4.5 5.563 6.625
Copper, Sch 40, 48" Spacing, 24kA
1 Span, 1 Fixed 9 15 19 25 32 39 43 52 52
2 Spans, Middle Fixed 7 12 15 20 26 32 35 43 42
3+ Spans, 1 Fixed 8 13 17 22 28 34 38 46 46

Aluminum, 6063-T6 Alloy, Sch 40, 48" Spacing, 24kA

1 Span, 1 Fixed 9 14 19 26 33 38 44 57 70
2 Spans, Middle Fixed 8 12 16 21 27 32 36 47 57
3+ Spans, 1 Fixed 8 13 17 23 29 34 39 50 61

Ampacity @ 40°C rise over 30°C, 2fps wind

Cu 850 1270 1570 1990 2540 3020 3365
Al, 6063-T6 Alloy 681 984 1234 1663 2040 2347 2664 3348 4064
Note: Spans should be applied only to specified conditions.

Ampacities 1 2 3 Note:
1/4"x4" Al Bar 980 1760 2462 Current ratings based on 30°C temperature rise over 40°C
ambient horizontally mounted conductors with a 2ft/sec
1/4"x5" Al Bar 1184 2092 2905 crosswind.
3-1/4"x3-1/4"x1/4" Al Angle 1902
4"x4"x1/4" Al Angle 2236
4"x4" IWCB 3360
4"x6" IWCB 4470
8"x8" IWCB 7550
1 - 500 MCM CU 810 1296
1 - 750 MCM CU 1040 1664
1 -1000 MCM CU 1240 1984

NEMA Clearances for Outdoor Substations

Nom. Voltage (kV) 15 25 34.5 46 69 115 161
BIL (kV) 110 150 200 250 350 550 750
Cond Spacing
Ph-Ph (Cl to Cl) 2'0" 2'6" 3'0" 4'0" 5'0" 7'0" 9'0"
Ph-Ground 10" 12" 15" 1'6" 2'5" 3'7.5" 4'10"
Clearance above Grade 9' 10' 10' 10' 11' 12' 14'
Switch Spacing (Cl to Cl)
Horngap 3'0" 4'0" 5'0" 6'0" 7'0" 10'0" 14'0"
Vert. Break Disc. 2'0" 2'6" 3'0" 4'0" 5'0" 7'0" 9'0"
Hor. Break Disc. 2'6" 3'0" 4'0" 5'0" 6'0" 9'0" 13'0"
Min. Phase Spacing
Metal to Metal 12" 15" 18" 21" 31" 53" 72"
Strain Insulators 10" Dia.
Number per String 2 3 4 4 5 8 12

Station Post Insulators

Upright Underhung Bottom

Cantilever Cantilever Top BC BC Height Leakage
BIL KV TR No (lbs) (Lbs) (in) (in) (in) (in)
95 202 2000 2000 3 3 7.5 10.5
95 222 4000 4000 5 5 7.5 10.5
110 205 2000 2000 3 3 10 15.5
110 225 4000 4000 5 5 12 15.5
150 208 2000 2000 3 3 14 24
150 227 4000 4000 5 5 15 24
200 210 2000 2000 3 3 18 37
200 231 4000 4000 5 5 20 37
250 214 2000 2000 3 3 22 43
250 267 4000 4000 5 5 24 43
350 216 1500 1500 3 3 30 72
350 278 3000 3000 5 5 30 72
550 286 1700 1700 5 5 45 99
550 287 2600 2600 5 5 45 99
650 288 1400 1400 5 5 54 116
650 289 2200 2200 5 5 54 116
750 291 1200 1200 5 5 62 132
750 295 1850 1850 5 5 62 132
900 304 950 950 5 5 80 165
900 308 1450 1450 5 5 80 165
 NESC Loading Zone Heavy (Heavy, Medium or Light) Wind, psf: 4 Radial Ice (In.):
Bus Material 6061-T6 (6063-T6, 6061-T6,Cu) Mod of Elast E: 1.0E+07 Max Fiber Stress Fb:
Pipe Schedule 40
Max Short Circuit 24000
Ø-Ø Spacing (In.) 48
Support Type 2 (1-5) Kse: 0.82 Kde: 9.34

Vibration
Sect SS Red Mom of Short Ice Wind Dampening Total Bus
Mod Factor Wgt of Bus Inertia Circuit Loading Loading Weight Loading
Size OD S Ksc Wc I Fsc Wi Fw Dw Ft
1 1.315 0.1328 0.67 0.581 0.0873 30.070 1.125 0.769 0 30.885
1.5 1.900 0.3262 0.67 0.94 0.3099 30.070 1.488 0.963 0 31.127
2 2.375 0.5606 0.67 1.264 0.6657 30.070 1.783 1.121 0.367 31.376
2.5 2.875 1.064 0.67 2.004 1.53 30.070 2.093 1.287 0.367 31.672
3 3.500 1.724 0.67 2.621 3.017 30.070 2.480 1.494 0.367 32.034
3.5 4.000 2.394 0.67 3.151 4.788 30.070 2.790 1.660 0.546 32.386
4 4.500 3.214 0.67 3.733 7.232 30.070 3.100 1.826 1.093 32.866
5 5.563 5.451 0.67 5.057 15.16 30.070 3.759 2.179 1.611 33.892
6 6.625 8.498 0.67 6.564 28.15 30.070 4.418 2.532 1.79 35.013
8 8.625 16.813 0.67 9.878 72.51 30.070 5.658 3.196 1.79 37.507
3x3 3.000 0.54 0.67 1.68 1.18 34.733 3.400 1.328 0 36.417

Note: For all equations, see RUS Bulletin 1724E-300 Design Guide for Rural Substations , Chapter 4 Section 4.11 - Rigid B
 Radial Ice (In.): 0.5
Max Fiber Stress Fb: 28000

Min Cant Max Bus

Strength Span Bus Defl (RUS)
Ws Lm Ld 1/150 y (RUS) Ld 1/200 (RUS) y 1 Span 2 Spans 3+ Spans
1806 9.0 23 1.874 0.120 15 0.892 0.890 Err:522 9 8
2362 14.0 30 2.435 0.285 20 1.209 1.207 Err:522 14 Err:522
2775 18.3 36 2.847 0.484 24 1.447 1.444 Err:522 18 Err:522
3157 25.1 40 3.222 1.000 29 1.730 1.727 Err:522 25 Err:522
3644 31.8 46 3.695 1.621 34 2.016 2.013 Err:522 32 Err:522
4019 37.3 51 4.053 2.245 37 2.235 2.232 Err:522 37 Err:522
4380 42.9 55 4.395 2.991 41 2.448 2.444 Err:522 43 Err:522
5123 55.0 64 5.083 4.980 48 2.877 2.873 Err:522 55 Err:522
5835 67.6 72 5.727 7.608 55 3.287 3.282 Err:522 68 Err:522
7122 91.9 86 6.851 14.254 67 4.014 4.008 Err:522 92 Err:522
3531 16.7 39 3.134 0.313 25 1.476 1.474 Err:522 17 Err:522

Chapter 4 Section 4.11 - Rigid Bus Design.

 6063-T6 12KV 48" Ø-Ø 161KV 108" Ø-Ø
9 8 8 10.2 8.4 9.0 Err:522 -0.6 0.8 15.0 12.3
14 12 13 16.3 13.3 14.3 Err:522 -0.7 Err:522 23.8 19.5
19 16 17 21.6 17.7 19.0 Err:522 -0.7 Err:522 31.2 25.6
26 21 23 29.0 23.8 25.5 Err:522 -1.3 Err:522 41.5 34.1
33 27 29 37.2 30.5 32.7 Err:522 -1.4 Err:522 52.5 43.0
38 32 34 43.9 36.0 38.6 Err:522 -1.3 Err:522 61.0 50.0
44 36 39 50.7 41.6 44.6 Err:522 -1.3 Err:522 69.2 56.7
57 47 50 65.5 53.7 57.7 Err:522 -1.3 Err:522 86.2 70.7
70 57 61 82.0 67.3 72.2 Err:522 -0.3 Err:522 104.0 85.3
95 78 83 110.5 90.6 97.3 Err:522 -1.2 Err:522 132.6 108.7
17 14 15 17.2 14.1 15.2 Err:522 -2.6 Err:522 24.8 20.4
61KV 108" Ø-Ø
13.2 8.96 (0.04)
20.9 13.99 (0.06)
27.5 18.26 (0.08)
36.6 25.04 (0.11)
46.2 31.70 (0.14)
53.7 37.15 (0.16)
60.9 42.73 (0.18)
75.9 54.79 (0.24)
91.5 67.31 (0.29)
116.7 91.48 (0.39)
21.9 16.64 (0.07)
 Schedule 40 Schedule 80

Nominal Unit Section Moment Unit Section

Bus Size Weight Modulus of Inertia Weight Modulus
(in) OD (lb/ft) (in3) (in4) (lb/ft) (in3)
1 1.315 0.581 0.1328 0.0873 0.751 0.1606
1.5 1.900 0.94 0.3262 0.3099 1.256 0.4118
2 2.375 1.264 0.5606 0.6657 1.737 0.7309
2.5 2.875 2.004 1.064 1.53 2.65 1.339
3 3.500 2.621 1.724 3.017 3.547 2.225
3.5 4.000 3.151 2.394 4.788 4.326 3.14
4 4.500 3.733 3.214 7.232 5.183 4.272
5 5.563 5.057 5.451 15.16 7.188 7.432
6 6.625 6.564 8.498 28.15 9.884 12.227
8 8.625 9.878 16.813 72.51 15.008 24.52

Schedule 40 Schedule 80

Nominal Unit Section Moment Unit Section

Bus Size Weight Modulus of Inertia Weight Modulus
(in) OD (lb/ft) (in3) (in4) (lb/ft) (in3)
1 1.315 1.83 0.1283 0.08434 2.5 0.1622
1.5 1.9 3.19 0.3347 0.318 4.18 0.416
2 2.375 4.21 0.5679 0.6744 5.78 0.7381
2.5 2.875 6.12 0.9991 1.436 8.82 1.352
3 3.5 8.72 1.743 3.051 11.79 2.247
3.5 4 11.38 2.6 5.2 14.34 3.162
4 4.5 12.9 3.361 7.563 17.22 4.31
4.5 5 14.42 4.22 10.55 21.05 5.866
5 5.563 16.12 5.305 14.76 23.62 7.431

Max Fiber
Support Stress
Type KSE KDE Material Fb
Fixed Both
Ends 1 1 4.5 Cu 20000

Fixed One
End-Simply
Supported 2 0.82 9.34 6061-T6 28000
Simply
Supported
Both Ends
(single
span) 3 0.82 22.5 6063-T6 20000

Simply
Support
(two equal
spans) 4 0.82 9.34

Simply
Supported
(three or
more equal
spans) 5 0.88 11.9

UPRIGHT UNDERHUNG BOLT CIRCLE

CANTILEVER CANTILEVER
BIL TR STRENGTH STRENGTH HEIGHT LEAKAGE
kV NO. (LBS) (LBS) TOP IN. BOTTOM IN. IN. DISTANCE IN.
95 202 2000 2000 3 3 7.5 10.5
95 202 4000 4000 5 5 7.5 10.5
110 205 2000 2000 3 3 10 15.5
110 225 4000 4000 5 5 12 15.5
150 208 2000 2000 3 3 14 24
150 227 4000 4000 5 5 15 24
200 210 2000 2000 3 3 18 37
200 231 4000 4000 5 5 20 37
250 214 2000 2000 3 3 22 43
250 267 4000 4000 5 5 24 43
350 216 1500 1500 3 3 30 72
350 278 3000 3000 5 5 30 72
550 286 1700 1700 5 5 45 99
550 287 2600 2600 5 5 45 99
650 288 1400 1400 5 5 54 116
650 289 2200 2200 5 5 54 116
750 291 1200 1200 5 5 62 132
750 295 1850 1850 5 5 62 132
900 304 950 950 5 5 80 165
900 308 1450 1450 5 5 80 165
1050 312 800 800 5 5 92 198
1050 316 1250 1250 5 5 92 198
1050 362 2300 2300 7 7 92 198
1300 324 1000 1000 5 5 106 231
1300 367 1450 1450 5 7 106 231
 1300 368 2000 2000 7 7 106 231
1300 369 2050 2050 5 7 106 231

Outside lnside
Nominal Diameter Diameter
Size (Inches) (Inches) CURRENT RATINGS IN AMPERES*
30° C Rise 40° C Rise 50° C Rise
STANDARD PIPE SIZES
1 1.315 1.062 850 975 1,080
1.5 1.9 1.6 1,270 1,445 1,600
2 2.375 2.062 1,570 1,780 1,980
2.5 2.875 2.5 1,990 2,275 2,525
3 3.5 3.062 2,540 2,870 3,225
4% 4 3.5 3,020 3,465 3,860
4 4.5 4 3,365 3,810 4,305
EXTRA HEAVY PIPE SIZES
1 1.315 0.951 1,000 1,140 1,255
31-Dec 1.9 1.494 1,445 1,650 1,830
2 2.375 1.933 1,830 2,080 2,325
2.5 2.875 2.315 2,365 2,720 3,020
3 3.5 2.892 2,970 3,365 3,710
3.5 4 3.358 3,380 3,860 4,255
4 4.5 3.818 3,840 4,350 4,850
* 40°C Ambient, 98% Conductivity, 60Hz, 2fps horizontal wind
chedule 80 Aluminum Single Angle (L) Conductors

Moment Section
of Inertia Angle Size Thickness Section Area Weight Moment of Modulus Radius of
(in4) (in.) (in.) (in.2) (Ibs./ft) Inertia (in.4) (in.3) Gyration (in.)
0.1056 2 /2 x 2 1/2
1
1/4 1.19 1.40 0.69 0.39 0.76

0.3912 2 1/2 x 2 1/2 3/8 1.74 2.05 0.98 0.56 0.75

0.8679 3x3 1/4 1.43 1.68 1.18 0.54 0.91
1.924 3x3 3/8 2.10 2.47 1.70 0.80 0.90
3.894 3x3 1/2 2.74 3.23 2.16 1.04 0.89
6.281 4x4 1/4 1.94 2.28 2.94 1.00 1.23
9.611 4x4 3/8 2.86 3.38 4.26 1.48 1.22
20.67 4x4 1/2 3.75 4.41 5.46 1.93 1.21
40.501 4x4 5/8 4.61 5.42 6.56 2.36 1.19
105.743

chedule 80

Moment
of Inertia
(in4)
0.1066
0.3952
0.8765
1.944
3.932
6.325
9.698
14.62
20.67
 Recommended ACSR Size to Prevcent Vibration

Recommended
Nominal Maximum Min. Size of Weight
Bus Size Safe Span ACSR Per Foot
in Length MCM lbs
1 5 0
1.5 7 0
2 9 266.8 0.367
2.5 10.75 266.8 0.367
3 13.25 266.8 0.367
3.5 15.25 397.5 0.546
4 17 795 1.093
5 21.25 1431 1.611
6 25.25 1590 1.79
8 1590 1.79
 Physical & Electrical Properties of Alum

6063-T6

A B
Outside Inductive
Diameter Wall reactance 1 DC
of Tube in Thickness ft spacing 60 Resistance 60 Hz
Nominal in Area Weight Hz microhm/ at 20°C Rac/RDC
Size in sq in Ibs/ft ft microhms/ ft at 70°C
Schedule 40 Pipe
1 1.315 0.133 0.494 0.581 68.24 31.120 1.00039
1 1/2 1.900 0.145 0.800 0.940 59.45 19.220 1.00064
2 2.375 0.154 1.075 1.264 54.15 14.300 1.00082
2 1/2 2.875 0.203 1.704 2.004 49.85 9.019 1.00220
3 3.500 0.216 2.228 2.621 45.19 6.897 1.00300
3 1/2 4.000 0.226 2.680 3.151 42.05 5.736 1.00380
4 4.500 0.237 3.174 3.733 39.28 4.842 1.00470
5 5.563 0.258 4.300 5.057 34.31 3.574 1.00680
6 6.625 0.280 3.381 6.364 30.23 2.754 1.00950
Schedule 80 Pipe
1 1.315 0.179 0.639 0.751 68.81 24.060 1.00100
1 1/2 1.900 0.200 1.068 1.256 39.89 14.390 1.00200
2 2.375 0.218 1.477 1.737 34.56 10.400 1.00280
2 1/2 2.875 0.276 2.254 2.650 50.23 6.820 1.00720
3 3.500 0.300 3.016 3.547 45.55 5.096 1.01030
3 1/2 4.000 0.318 3.678 4.326 42.39 4.178 1.01380
4 4.300 0.337 4.407 3.183 39.61 3.487 1.01710
5 5.563 0.375 6.112 7.188 34.63 2.515 1.02600
6 6.625 0.432 8.405 9.884 30.58 1.829 1.04570

Notes:
1
Current ratings listed in the Tables are based on 30°C temperature rise over 40°C ambient horizontally
effects, generally assumed not to be significant if spacing is 18 in. or over. Conduction of heat by supp
2 Conductors with a 2ft/sec crosswind. Nominal oxidized surface (e=0.50)
3
Current Ratings for direct current are close to those of alternating current for all except the larger size
4
NEMA Standard SG1-3.02 (7/13/60) lists current rating for tubes of 57%-61 % IACS conductivity, but w
53% IACS conductivity of 6063-T6 alloy (and 43% for 6061-T6 alloy), the ratings differ somewhat from

Physical & Electrical Properties of Integral-Web Channel

Bus Conductors - 6101-T6 Alloy 55.0% IACS Conductivity (minimum)
 Wall
Size Thickness Moment of Inertia, in4 DC
Resistance
Rdc-20°C
Area sq Weight microhms
A in B in T in in Ib/ft Ix-x Iy-y per ft
4 4 0.156 2.439 2.87 3.876 6.213 6.88
4 4 0.250 3.781 4.45 5.788 9.213 4.42
4 4 0.312 4.460 5.25 6.892 10.94 3.75
6 4 0.250 4.780 5.62 16.35 12.74 3.50
6 4 0.375 6.020 7.10 14.50 14.00 2.78
6 4 0.375 6.950 8.17 22.91 17.45 2.41
6 5 0.375 7.600 8.94 25.19 29.78 2.20
6 6 0.375 8.600 10.15 29.73 45.98 1.95
6 6 0.550 11.22 13.19 40.05 60.86 1.49
7 7 0.500 12.84 15.10 64.83 95.67 1.30
8 5 0.375 9.080 10.68 52.88 37.59 1.84
8 5 0.500 11.75 13.82 66.84 46.67 1.42
8 8 0.500 16.12 18.96 103.5 152.3 1.04
9 9 0.625 20.04 23.57 162.3 240.1 0.83
10 10 0.625 23.50 27.64 255.6 362.4 0.71

Notes:

1. Current ratings are based on 6101-T61 alloy with standard vent-holes in web. For 6101-T6 reduce the rating by
40°C ambient in still but unconfined air, normally oxidized surface (e=0.35) and similarly for outdoor ratings, except 2
assumed with spacing sufficient to eliminate proximity effects, generally assumed to be 18-in. or over. For temperatu
for 30°C may be increased about 30 percent. Indoor ratings (D-C and A-C) calculated by computer and verified by te

2. For vent and notch arrangements, consult your AFL Sales Representative. The interior perimeter varies accordi
as to their location per NEMA spacing. The 12 in. x 12 in. size is a opposite of two symmetric extrusions bolted toge

Stranded Copper Conductor

Diameter (mils) Hard Drawn

DC
Resistance
Weight (ohms/100
Size Stranding (lbs/1000 Individua Complete Rated 0 ft)
(AWG) Stranding Class ft) l Wires Conductor Strength (lbs) @20°C
STRANDED
1/0 7 A. AA 326.1 123 368 4752 1042
2/0 7 A. AA 410.9 138 414 5926 08267
2/0 19 B 410.9 B4 418 5690 08267
 3/0 7 A. AA 518.1 155 464 7366 06556
4/0 7 A. AA 553.3 174 522 9154 05199
4/0 19 B 553.3 106 528 9617 05199
250 19 A 771.9 115 574 11360 04400
250 37 B 771.9 B2 575 11600 04400
300 19 A 926.2 126 628 13510 03667
350 19 A 1080.6 136 679 15590 03143
500 37 AB 1543.8 116 814 22510 02200
600 37 AAA 1852.5 127 891 27020 01834
750 61 AB 2315.6 111 998 34090 01467
1000 61 AB 3087.5 128 1152 45030 01100

■Ampacity based on 75*C conductor temperature; 25*C ambient temperature; 2 ft./sec. wind in sun.
Current Rating of Rectangular Alumi
Amperes, for 6101-T61 Alloy 57% I A

Copper Pipe Bus

Outside lnside
Nominal Diameter Diameter Size
Size (Inches) (Inches) CURRENT RATINGS IN AMPERES* (Inches)
30° C Rise 40° C Rise 50° C Rise ¼X1
STANDARD PIPE SIZES 1½
1 1.315 1.062 850 975 1,080 2
1.5 1.9 1.6 1,270 1,445 1,600 3
2 2.375 2.062 1,570 1,780 1,980 4
2.5 2.875 2.5 1,990 2,275 2,525 5
3 3.5 3.062 2,540 2,870 3,225 6
4% 4 3.5 3,020 3,465 3,860 7
4 4.5 4 3,365 3,810 4,305 ⅜X2
EXTRA HEAVY PIPE SIZES 3
1 1.315 0.951 1,000 1,140 1,255 4
31-Dec 1.9 1.494 1,445 1,650 1,830 5
2 2.375 1.933 1,830 2,080 2,325 6
2.5 2.875 2.315 2,365 2,720 3,020 8
3 3.5 2.892 2,970 3,365 3,710 10
3.5 4 3.358 3,380 3,860 4,255 ½X3
4 4.5 3.818 3,840 4,350 4,850 4
* 40°C Ambient, 98% Conductivity, 60Hz, 2fps horizontal wind 5
6
8
10

Size
(Inches)
 ¼X1
1½
2
3
4
5
6
7
⅜X2
3
4
5
6
8
10
½X3
5
6
8

Notes:
1

2
3
4

Physical & Electrical Properties of Uniform-Thickness

Angle BUS Conductors - 6101-T6 alloy 55.0% lACS Conductivity (minimum)
Minimum Distance to
Size (3) Moment of Inertia in4 Neutral Axis
Weight
W in T in Area sq in Ib/ft lx or y Iz x or y z
3 1/4 1/4 1.57 1.83 1.60 0.65 0.91 1.30
 4 1/4 1.93 2.27 3.02 1.18 1.09 1.51
4 3/8 2.85 3.36 4.35 1.75 1.14 1.60
4 1/2 3/8 3.23 3.80 6.31 2.61 1.26 1.77
5 3/8 3.60 4.24 8.75 3.50 1.39 1.96

Notes:
1 Indoor current ratings are based on 30°C rise over 40°C ambient in still but unconfined air, normally oxidized surfac
crosswind (e=0.50). Horizontal mounting is assumed with spacing sufficient to eliminate proximity effects, generally
and Tuttle. Outdoor ratings from IEEE paper by Prager, Pemberton, Craig and Bleshman.

2 Back-to-back angles are to be considered as separate members; not as a composite.

3 Alignment grooves are extruded to facilitate centering of holes according to NEMA standard spacings.
4 A modification of this design has a lug at top that does not interfere with bolting, yet it strengthens the shape again
lateral short circuit forces. For equal weight of shape, the z-z radius of gyration is increased by 20 percent. The stres
al Properties of Aluminum

6063-T6 6061-T6

Current
Ratings Current
AC Amp at 60 DC AC Ratings
Resistance Hz (1) (2) Resistance 60 Hz Resistance Amp at 60 Hz
at 70°C 60 Hz (3) (4) at 20°C Rac/RDC at 70°C 60 Hz (1) (2) (3) (4)
microhms/ft Outdoor microhms/ft at 70°C microhms/ft Outdoor
hedule 40 Pipe
36.580 681 38.360 1.00032 43.820 622
22.600 984 23.690 1.00046 27.070 900
16.820 1234 17.630 1.00055 20.140 1128
10.620 1663 11.170 1.00150 12.710 1520
8.126 2040 8.500 1.00180 9.725 1865
6.761 2347 7.070 1.00220 8.091 2145
5.712 2664 5.968 1.00270 6.834 2436
4.224 3348 4.406 1.00400 5.051 3063
3.263 4064 3.394 1.00540 3.897 3719
hedule 80 Pipe
28.300 774 29.650 1.00075 33.840 707
16.940 1137 17.730 1.00150 20.280 1039
12.260 1446 12.820 1.00210 14.670 1322
8.071 1907 8.406 1.00390 9.647 1746
6.050 2363 6.281 1.00490 7.225 2199
4.972 2735 5.150 1.00750 5.935 2507
4.168 3118 4.298 1.00950 4.965 2862
3.032 3949 3.099 1.01650 3.604 3631
2.247 4891 2.254 1.02120 2.656 4532

se over 40°C ambient horizontally mounted conductors, with spacing sufficient to eliminate proximity
over. Conduction of heat by supporting structures and taps can appreciably affect the ratings.
50)

rrent for all except the larger sizes; and for them, the increase for dc bus is about 1.5 percent.
7%-61 % IACS conductivity, but without stated emissivity factors. However, even after adjustment for the
he ratings differ somewhat from those of this table.
 Inductive AC 60 Hz
Reactance Resistanc
Xa-60Hz 1 e Rac-
Current Rating ft spacing Rac/ 70°C Current Rating AC-60HZ
DC 70°C e=0.35 microhms RDC70°C microhms Outdoor
Indoors per ft 60HZ per ft Indoor e=0.35 e= 0.50
2260 39.02 1.020 7.017 2240 2520
2810 39,76 1.035 4.579 2276 3115
3050 40.80 1.050 3.940 2980 3360
3480 34.80 1.050 3.670 3400 3780
3900 36.60 1.080 3.000 3760 4180
4200 .... 1.090 2.630 4020 4470
4500 32.50 1.110 2.440 4320 4800
5020 27.60 1.110 2.160 4760 5270
5730 31.40 1.220 1.820 5190 5740
6530 27.60 1.210 1.570 5940 6540
5350 29.10 1.120 2.064 5060 5560
6090 30.00 1.280 1.820 5380 5910
7740 24.70 1.260 1.310 6890 7550
9060 21.60 1.370 1.140 7740 8450
10260 19.10 1.420 1.010 8610 9350

6101-T6 reduce the rating by 2 percent. Indoor ratings are based on 30°C rise over
rly for outdoor ratings, except 2 ft/sec cross wind (e=0.50). Horizontal mounting is
e 18-in. or over. For temperature rise of 50°C above 40°C ambient, the indoor ratings
by computer and verified by test rounded. Outdoor ratings are calculations only.

terior perimeter varies according to the washer diameters that are to be accommodated, and
mmetric extrusions bolted together.

r Conductor
Medium-Hard Drawn Soft-Drawn (Annealed)

DC DC
Resistanc Resistanc
e e
(ohms/100 (ohms/100
Rated Strength 0 ft) Rated 0 ft) Allowable
(lbs) @20°C Strength (lbs) @20°C Ampacity
ED
3705 .1037 3221 .1002 310
4640 .08224 4062 07949 355
4765 .08224 4024 07949 355
 5812 .06522 5118 06304 410
7278 .05172 5459 04999 480
7479 .05172 5453 04999 480
8836 .04378 7627 04231 530
8952 .04378 7940 04231 530
10530 .03648 9160 03526 590
12200 .03127 10680 03022 650
17550 .02189 15240 02116 810
21060 .01825 18300 01763 910
26510 .01459 22890 01410 1040
35100 .01094 30500 01058 1240

c. wind in sun.
urrent Rating of Rectangular Aluminum Bus-Bar Arrangements
Amperes, for 6101-T61 Alloy 57% I ACS Conductivity (see footnotes!

[] 1 Bar [][] 2 Bars [][][] 3 Bars [][][][]

308 601 887 1168
429 817 1194 1561
545 1021 1480 1915
768 1410 2000 2530
980 1760 2462 3081
1184 2092 2905 3625
1381 2413 3338 4146
1760 3034 4183 5152
678 1278 1831 2332
941 1709 2384 2946
1191 2099 2893 3574
1429 2483 3387 4178
1657 2347 3857 4765
2098 3569 4774 5875
2534 4239 5632 6941
1074 1991 2742 3297
1369 2416 3264 3940
1634 2828 3778 4580
1892 3230 4284 5210
2393 4014 5276 6246
2880 4779 6256 7579
[][][][]
[][][]
[][]

1 Bar 2 Bars 3 Bars

[]
 300 580 765 880
416 785 1020 1180
530 980 1280 1460
735 1310 1700 1940
930 1600 2050 2330
1120 1830 2330 2610
1270 2010 2540 2800
1520 2320 2840 3080
660 1170 1490 1700
905 1550 1960 2220
1130 1860 2340 2630
1340 2110 2650 2940
1520 2330 2940 3200
1820 2700 3270 3490
1050 1650 2080 2340
1300 1960 2470 2750
1520 2240 2780 3090
1710 2490 3050 3330
2050 2900 3490 3720

Ratings based on 30°C rise over 40°C ambient in still but confined air (e=0.35), corresponding to usual
indoor temperature. Vertical bar ampacity based on work by House and Tuttle. Horizontal bar ampacity
from industry sources.
Space between bars is assumed equal bar thickness.
For ac phase spacings less than 18 inches an allowance for proximity effect must be made.
Ratings are based on horizontal mounting, in air with no attachments.

vity (minimum)

Inductive Resistanc e at 70°C AC Current Rating 60 Hz

Reactance 1 -ft e at 20°C 60Hz Amp (1)
Spacing microhms Rac/Rdc at microhms Indoor
microhms/ft /ft 70°C 60 Hz /ft e=0.35 Outdoor e=0.50
51.41 11.20 1.024 11.49 1300 1902
 46.60 9.07 1.045 9.46 1550 2236
46.62 6.14 1.115 6.85 1850 2654
43.93 5.42 1.145 6.20 2050 2885
41.52 4.86 1.175 5.71 2250 3130

ned air, normally oxidized surface (e=0.35). Outdoor ratings are based similarly, but with 2 ft/sec
inate proximity effects, generally assumed to be 18-in. or over. Indoor ratings based on work by House
hman.

e.
standard spacings.
et it strengthens the shape against tendency to roll-over to the z-z axis in long spans subjected to large
ncreased by 20 percent. The stress that causes roll-over is thereby increased about 40 percent.
 4 Bars
1168
1561
1915
2530
3081
3625
4146
5152
2332
2946
3574
4178
4765
5875
6941
3297
3940
4580
5210
6246
7579

4 Bars
 880
1180
1460
1940
2330
2610
2800
3080
1700
2220
2630
2940
3200
3490
2340
2750
3090
3330
3720

sponding to usual
ntal bar ampacity