BUSBAR SIZE SELECTOR

 

Required
Ampacity,*
(Range)
Amp

Bus Bar Dimensions, In.**

30 C° Rise

50 C° Rise

65 C° Rise

100 (100-149)

1/16x1/2,1/16x3/4

1/16x1/2

 

150 (150-199)

1/16x1
1/8x1/2
3/16x1/2

1/16x3/4

1/16x1/2

200 (200-249)

1/8x3/4
1/4x1/2

1/8x1/2

1/16x3/4
1/8x1/2

250 (250-299)

1/16x1 1/2
1/8x1
3/16x3/4

1/16x1
1/8x3/4
3/16x1/2

1/16x1

300 (300-349)

1/16x2
3/16x1
1/4x3/4

1/4x1/2

1/8x3/4
3/16x1/2

350 (350-399)

1/8x1 1/2

1/16x1 1/2
1/8x1
3/16x3/4

1/4x1/2

400 (400-449)

1/4x3/4
3/8x3/4

1/4x3/4

1/4x1/2

400 (400-449)

1/4x1
3/8x3/4

1/4x3/4

1/16x1 1/2
1/8x1
3/16x3/4

450 (450-499)

1/8x2
3/16x1/2

1/16x2
3/16x1

1/4x3/4

500 (500-599)

1/4x1 1/2
3/8x1

1/8x1 1/2
1/4x1
3/8x3/4

1/16x2
1/8x1 1/2
3/16x1

600 (600-699)

1/8x2 1/2
3/16x2
1/2x1
1/2x1

1/8x2
3/16x1 1/2
1/4x1

1/4x1
3/8x3/4

700 (700-799)

1/8x3
3/16x2 1/2
1/4x2
3/8x1 1/2

1/4x1 1/2

1/8x2
3/16x1 1/2
3/8x1

800 (800-899)

1/8x3 1/2
3/16x3
1/4x2 1/2
3/8x2

1/8x2 1/2
3/16x2
1/2x1

1/4x1 1/2

900 (900-999)

1/8x4
3/16x3 1/2
1/4x3

1/8x3
3/16x2 1/2
1/4x2
3/8x1 1/2

1/8x2 1/2
1/2x1

1000 (1000-1249)

3/16x4
1/4x3 1/2
3/8x2 1/2, 3/8x3
1/2x2, 1/2x2 1/2

1/8x4
3/16x3
1/4x2 1/2
3/8x2

1/8x3
3/16x2 1/2
1/4x2
3/8x1 1/2

1250 (1250-1499)

1/4x4
3/8x3 1/2
1/2x3

3/16x3 1/2, 3/16x4
1/4x3
3/8x2 1/2
1/2x2

1/8x4
3/16x3
1/4x2 1/2
3/8x2  

1500 (1500-1749)

1/4x5
3/8x4
1/2x3 1/2, 1/2x4

1/4x3 1/2

1/4x4
3/8x3
1/2x2 1/2

3/16x3 1/2 3/16x4
1/4x3
3/8x2 1/2
1/2x2

1750 (1750-1999)

1/4x6
3/8x5

 
3/8x3 1/2
1/2x3

1/4x3 1/2, 1/4x4
3/8x3
1/2x2 1/2

2000 (2000-2499)

1/4x8
3/8x6
1/2x5, 1/2x6
3/4x4, 3/4x5

1/4x6
3/8x5
1/2x4

1/4x5
3/8x4
1/2x3 1/2

2500 (2500-2999)

1/4x10
3/8x8
3/4x6

3/8x6
1/2x5
3/4x4

1/4x6
3/8x5
1/2x4

3000 (3000-3499)

1/4x12
3/8x10
1/2x8

1/4x8
1/2x6
3/4x5

1/4x8
3/8x6
1/2x5
3/4x4

3500 (3500-3999)

 
3/8x12
1/2x10
3/4x8

1/4x10
3/8x8
 3/4x6

1/2x6
3/4x5

4000 (4000-4499)

 1/2x12
3/4x10

1/4x12
3/8x10
1/2x8

1/4x10
3/8x8
3/4x6

4500 (4500-4999)

3/4x12

1/2x10
3/4x8

1/4x12
3/8x10
1/2x8

5000 (5000-5999)

 

3/8x12
1/2x12
3/4x10

3/8x12
1/2x10
3/4x8

* For 60 Hz systems

 

** Table gives bus bar cross sections which will probably be large enough for ampacities within each range.

 

 

 

Cross Reference

 

Dimensions,
In.

Area

Weight
Per
Foot,
Lb

DC
Resistance
at 20° C,
Microhms
Per Ft

30 C° Rise

50 C° Rise

65 C° Rise

Square In.

Circular
Mils,
Thousands

Skin Effect
Ratio at
70° C

60-Hz
Ampacity,*
Amp

Skin Effect
Ratio at
90° C

60-Hz
Ampacity,*
Amp

Skin Effect
Ratio at
105° C

60-Hz
Ampacity,*
Amp

1/16 x 1/2
1/16 x 3/4
1/16 x 1
1/16 x 1 1/2
1/16 x 2

0.0312
0.0469
0.0625
0.0938
0.125  

39.7
59.7
79.6
119   
159   

0.121
0.181
0.241
0.362
0.483

264.0    
175.0    
132.0    
87.7    
65.8    

1.00
1.00
1.00
1.00
1.01

103
145
187
270
345

1.00
1.00
1.00
1.00
1.01

136
193
250
355
460

1.00
1.00
1.00
1.00
1.01

157
225
285
410
530

1/8 x 1/2
1/8 x 3/4
1/8 x 1
1/8 x 1 1/2
1/8 x 2
1/8 x 2 1/2
1/8 x 3
1/8 x 3 1/2
1/8 x 4

0.0625
0.0938
0.125  
0.188  
0.250  
0.312  
0.375  
0.438  
0.500  

79.6
119   
159   
239   
318   
397   
477   
558   
636   

0.241
0.362
0.483
0.726
0.966
1.21  
1.45  
1.69  
1.93  

132.0    
87.7    
65.8    
43.8    
32.9    
26.4    
21.9    
18.8    
16.5    

1.00
1.00
1.01
1.01
1.02
1.02
1.03
1.04
1.04

153
215
270
385
495
600
710
810
910

1.00
1.00
1.01
1.01
1.02
1.02
1.03
1.03
1.04

205
285
360
510
660
800
940
1,100
1,200

1.00
1.00
1.01
1.01
1.02
1.02
1.03
1.03
1.04

235
325
415
590
760
920
1,100
1,250
1,400

3/16 x 1/2
3/16 x 3/4
3/16 x 1
3/16 x 1 1/2
3/16 x 2
3/16 x 2 1/2
3/16 x 3
3/16 x 3 1/2
3/16 x 4

0.0938
0.141  
0.188  
0.281  
0.375  
0.469  
0.562  
0.656  
0.750  

119   
179   
239   
358   
477   
597   
715   
835   
955   

0.362
0.545
0.726
1.09  
1.45  
1.81  
2.17  
2.53  
2.90  

87.7    
58.4    
43.8    
29.3    
21.9    
17.5    
14.6    
12.5    
11.0    

1.00
1.01
1.01
1.02
1.03
1.04
1.05
1.07
1.09

195
270
340
480
610
740
870
990
1,100

1.00
1.01
1.01
1.02
1.03
1.04
1.05
1.06
1.08

260
360
455
630
810
980
1,150
1,300
1,450

1.00
1.01
1.01
1.02
1.03
1.03
1.04
1.06
1.07

300
415
520
730
940
1,150
1,350
1,500
1,700

1/4 x 1/2
1/4 x 3/4
1/4 x 1
1/4 x 1 1/2
1/4 x 2
1/4 x 2 1/2
1/4 x 3
1/4 x 3 1/2
1/4 x 4
1/4 x 5
1/4 x 6
1/4 x 8
1/4 x 10
1/4 x 12

0.125  
0.188  
0.250  
0.375  
0.500  
0.625  
0.750  
0.875  
1.00    
1.25    
1.50    
2.00    
2.50    
3.00    

159   
239   
318   
477   
637   
796   
955   
1,110   
1,270   
1,590   
1,910   
2,550   
3,180   
3,820   

0.483
0.726
0.966
1.45  
1.93  
2.41  
2.90  
3.38  
3.86  
4.83  
5.80  
7.73  
9.66  
11.6    

65.8    
43.8    
32.9    
21.9    
16.5    
13.2    
11.0    
9.40  
8.23  
6.58  
5.49  
4.11  
3.29  
2.74  

1.01
1.01
1.02
1.03
1.04
1.06
1.08
1.10
1.12
1.16
1.18
1.23
1.27
1.31

240
320
400
560
710
850
990
1,150
1,250
1,500
1,750
2,250
2,700
3,150

1.01
1.01
1.02
1.03
1.04
1.06
1.08
1.09
1.11
1.15
1.17
1.22
1.26
1.30

315
425
530
740
940
1,150
1,300
1,500
1,700
2,000
2,350
3,000
3,600
4,200

1.01
1.01
1.02
1.03
1.04
1.06
1.07
1.09
1.10
1.14
1.17
1.21
1.25
1.28

360
490
620
860
1,100
1,300
1,550
1,750
1,950
2,350
2,700
3,450
4,200
4,900

3/8 x 3/4
3/8 x 1
3/8 x 1 1/2
3/8 x 2
3/8 x 2 1/2
3/8 x 3
3/8 x 3 1/2
3/8 x 4
3/8 x 5
3/8 x 6
3/8 x 8
3/8 x 10
3/8 x 12

0.281  
0.375  
0.562  
0.750  
0.938  
1.12    
1.31    
1.50    
1.88    
2.25    
3.00    
3.75    
4.50    

358   
477   
715   
955   
1,190   
1,430   
1,670   
1,910   
2,390   
2,860   
3,820   
4,770   
5,730   

1.09  
1.45  
2.17  
2.90  
3.62  
4.35  
5.06  
5.80  
7.26  
8.69  
11.6    
14.5    
17.4    

29.3    
21.9    
14.6    
11.0    
8.77  
7.35  
6.28  
5.49  
4.38  
3.66  
2.74  
2.19  
1.83  

1.02
1.03
1.05
1.08
1.12
1.15
1.18
1.20
1.24
1.27
1.33
1.38
1.42

415
510
710
880
1,050
1,200
1,350
1,500
1,800
2,100
2,650
3,200
3,700

1.02
1.03
1.04
1.08
1.10
1.14
1.16
1.19
1.23
1.26
1.31
1.36
1.40

550
680
940
1,150
1,400
1,600
1,800
2,000
2,400
2,800
3,550
4,300
5,000

1.02
1.03
1.04
1.07
1.09
1.13
1.15
1.18
1.22
1.24
1.30
1.35
1.38

630
790
1,100
1,350
1,600
1,850
2,100
2,350
2,800
3,250
4,100
4,900
5,800

1/2 x 1
1/2 x 1 1/2
1/2 x 2
1/2 x 2 1/2
1/2 x 3
1/2 x 3 1/2
1/2 x 4
1/2 x 5
1/2 x 6
1/2 x 8
1/2 x 10
1/2 x 12

0.500  
0.750  
1.00    
1.25    
1.50    
1.75    
2.00    
2.50    
3.00    
4.00    
5.00    
6.00    

637   
955   
1,270   
1,590   
1,910   
2,230   
2,550   
3,180   
3,820   
5,090   
6,360   
7,640   

1.93  
2.90  
3.86  
4.83  
5.80  
6.76  
7.73  
9.66  
11.6    
15.5    
19.3    
23.2    

16.5    
11.0    
8.23  
6.58  
5.49  
4.70  
4.11  
3.29  
2.74  
2.06  
1.65  
1.37  

1.04
1.08
1.12
1.16
1.20
1.24
1.26
1.32
1.36
1.42
1.47
1.52

620
830
1,000
1,200
1,400
1,550
1,700
2,050
2,400
3,000
3,600
4,200

1.04
1.08
1.11
1.15
1.19
1.22
1.25
1.30
1.34
1.40
1.45
1.51

820
1,100
1,350
1,600
1,850
2,100
2,300
2,750
3,150
4,000
4,800
5,600

1.04
1.07
1.10
1.14
1.18
1.21
1.24
1.29
1.33
1.39
1.44
1.50

940
1,250
1,550
1,850
2,150
2,400
2,650
3,150
3,650
4,600
5,500
6,400

3/4 x 4
3/4 x 5
3/4 x 6
3/4 x 8
3/4 x 10
3/4 x 12

3.00    
3.75    
4.50    
6.00    
7.50    
9.00    

3,820   
4,770   
5,730   
7,640   
9,550   
11,500   

11.6    
14.5    
17.4    
23.2    
29.0    
34.8    

2.74  
2.19  
1.83  
1.37  
1.10  
0.914

1.42
1.48
1.52
1.60
1.67
1.72

2,050
2,400
2,800
3,500
4,200
4,900

1.40
1.46
1.50
1.58
1.64
1.69

2,750
3,250
3,750
4,700
5,600
6,500

1.38
1.44
1.48
1.56
1.62
1.67

3,150
3,750
4,300
5,400
6,500
7,500

* Applicable to typical in-service conditions (indoors, 40C° ambient temperature), horizontal run on edge, and free from external magnetic influences.

 

 

 

Copyright 1995-2002 SELCO USA, Inc.