Bus Bar Design Considerations

Busbar Design Considerations

TABLE 2. QUICK BUSBAR SIZE SELECTOR

Required Ampacity* Busbar Dimension, Inches**
  30 °C Rise 50 °C Rise 65 °C Rise
       
100-149 1/16 x 1/2
1/16 x 3/4
1/16 x 1/2  
150-199 16 x 1
1/8 x 1/2
3/16 x 1/2
1/16 x 3/4 1/16 x 1/2
200-249 1/8 x 3/4
1/4 x 1/2
1/8 x 1/2 1/16 x 3/4
1/8 x 1/2
250-299 1/16 x 1 1/2
1/8 x 1
3/16 x 3/4
1/16 x 1
1/8 x 3/4
3/16 x 1/2
1/16 x 1
300-349 1/16 x 2
3/16 x 1
1/4 x 3/4
1/4 x 1/2 1/8 x 3/4
3/16 x 1/2
350-399 1/8 x 1 1/2 1/8 x 1
3/16 x 3/4
1/4 x 1/2
400-449 1/4 x 1
3/8 x 3/4
1/4 x 3/4 1/16 x 1 1/2
1/8 x 1
3/16 x 3/4
450-499 1/8 x 2
3/16 x 1 1/2
1/16 x 2
3/16 x 1
1/4 x 3/4
500-599 1/4 x 1 1/2
3/8 x 1
1/8 x 1 1/2
1/4 x 1
3/8 x 3/4
1/16 x 2
1/8 x 1 1/2
3/16 x 1
600-699 1/8 x 2 1/2
3/16 x 2
1/2 x 1
1/8 x 2
3/16 x 1 1/2
3/8 x 1
1/4 x 1
3/8 x 3/4
700-799 1/8 x 3
3/16 x 2 1/2
1/4 x 2
3/8 1 1/2
1/4 x 1 1/2 1/8 x 2
3/16 x 1 1/2
3/8 x 1
800-899 1/8 x 3 1/2
3/16 x 3
1/4 x 2 1/2
3/8 x 2
1/8 x 2 1/2
3/16 x 2
1/2 x 1
1/4 x 1 1/2
900-999 3/16 x 3 1/2
1/4 x 3
3/16 x 2 1/2
1/4 x 2
3/8 x 1 1/2
3/16 x 2
1/2 x1
1000-1249 3/16 x 4
1/4 x 3 1/2
3/8 x 2 1/2
3/8 x 3
1/2 x 2
1/2 x 2 1/2
1/8 x 4
3/16 x 3
1/4 x 2 1/2
3/8 x 2
1/8 x 3
3/16 x 2 1/2
1/4 x 2
3/8 x 1 1/2
1250-14999 1/4 x 4
3/8 x 3 1/2
1/2 x 3
3/16 x 3 1/2
3/16 x 4
1/4 x 3
3/8 x 2 1/2
1/2 x 2
1/8 x 4
3/16 x 3
1/4 2 1/2
3/8 x 2
1500-1749 1/4 x 5
3/8 x 4
1/2 x 3 1/2
1/2 x 4
1/4 x 3 1/2
1/4 x 4
3/8 x 3
1/2 x 2 1/2
3/16 x 3 1/2
3/16 x 4
1/4 x 3
3/8 x 2 1/2
1/2 x 2
1750-1999 1/4 x 6
3/8 x 5
3/8 x 3 1/2
1/2 x 3
1/4 x 3 1/2
1/4 x 4
3/8 x 3
1/2 x 2 1/2
2000-2499 1/4 x 8
3/8 x 6
1/2 x 5
1/2 x 6
1/4 x 6
3/8 x 5
1/2 x 4
1/4 x 5
3/8 x 4
1/2 x 3 1/2
2500-2999 1/4 x 10
3/8 x 8
3/8 x 6
1/2 x 5
1/4 x 6
3/8 x 5
1/2 x 4

* For 60 Hz current.

** Table gives busbar cross section which will probably be large enough for Ampacities within each range. Knowing required ampacity, determine possible busbar dimensions from the table. Then check Table 1 to verify that size selected has the necessary ampacity. Example: Assume that required ampacity is 185 amps at 30 °C rise. Table 2 indicates that 1/16 x 1 in. size would probably be adequate. This is confirmed by Table 1 which lists the ampacity of 1/6 x 1 in. busbar as 187 amps.