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Busbar Profile vs. Current Density

The following chart shows the impact of changes in busbar size to the overall current density of the conductor.

Dimension, In.

Area

Weight Per Ft
in Lbs

Amperage

DC Resistance
at 20° C
 

30° C Rise

50° C Rise

65° C Rise

 

Sq. In

Circ Mils
Thousands

 

Amps/
Circ Mils

Amps
Per Sq. Ft.

Microhms
Per Sq. Ft.

Skin Effect
Ratio
at 90° C

60 Hz
Ampacity
Amp*

Skin Effect
Ratio
at 90° C

60 Hz
Ampacity
Amp*

Skin Effect
Ratio
at 90° C

60 Hz
Ampacity
Amp*

1/16 x 1/2

.0312

39.7

.121

385

3209

264.0

1.00

103

1.00

136

1.00

157

1/16 x 2

.125

159

.483

460

2760

65.8

1.01

345

1.01

460

1.01

530

1/8 x 1

.125

159

.483

589

2160

65.8

1.01

270

1.01

360

1.01

415

1/8 x 3 1/2

.438

558

1.69

688

1849

18.8

1.04

810

1.03

1100

1.03

1250

3/16 x 1

.188

239

.726

702

1808

43.8

1.01

340

1.01

455

1.01

520

3/16 x 3

.562

715

2.17

821

1548

14.6

1.05

870

1.05

1150

1.04

1350

1/4 x 3/4

.188

239

.726

746

1702

43.8

1.01

320

1.01

425

1.01

490

1/4 x 3

.750

955

2.90

965

1320

11.0

1.08

990

1.08

1300

1.07

1550

3/8 x 2 1/2

.938

1190

3.62

1133

1119

8.77

1.12

1050

1.10

1400

1.09

1600

1/2 x 1 1/2

.750

955

2.90

1150

1107

11.0

1.08

830

1.08

1100

1.07

1250

1/2 x 4

2.00

2550

7.73

1500

850

4.11

1.26

1700

1.25

2300

1.24

2650

1/2 x 10

5.00

4770

14.5

1998

640

1.65

1.48

3250

1.46

4800

1.44

3750

3/4 x 10

7.50

9550

7.73

2274

560

1.10

1.67

5600

1.64

5600

1.62

6500