Electrical Bus Bar Size Calculation

Consultant challenged contractor that.

Electrical bus bar size calculation.

Now you have to make a cable connection with busbar. The total current carrying capacity of the busbar is 1 2 area 1000 sqmm 1 2 1200 amps. When you are calculating the size of a busbar then you have to keep in mind its height and thickness of conductor plate that you use. Then check previous table to verify that size selected has the necessary ampacity.

Assume that required ampacity is 185 amps at 30 c rise. Calculate bus bar cross section area calculate current rating of bus bar calculate peak elector magnetic force between phase conductors calculate force on insulator of bus bar support. So for our load 80 x 5 or 40 x 10 or 50 x 8 sqmm busbar enough is enough. Example of busbar calculation.

Consultant recommended busbar size based on the thumb rule we noticed busbar size is low to carry 6300a. Let s consider we have a 600kva power transformer or a generator which have 400v as line voltage. So the bus bar 100x25x1 5 is suitable for 100 25 1 5 0 8 3000a incomer current. Calculation of busbar will denote by millimeter.

Knowing required ampacity determine possible bus bar dimensions from the table. Dc current when dealing with dc power the biggest concern is resistance per foot and the resulting voltage drop. Table 2 indicates that 1 16 x 1 in. Busbar size should be equal or more than of 6300a.

Required ampacity range amp. Typical size of the busbar available in the market. Size would probably be adequate. In case of copper bus bar the current carrying capacity is 1 2 max.

7 responses to panel design calculate size of bus bar excel prudhvi raju. Now total ampere we can get. Bus bar cross section area as per short circuit 626 sq mm select higher size for bus bar cross section area between 436 sq mm and 626 sq mm final calculated bus bar cross section area 626 sq mm actual selected bus bar size is 75 10 750 sq mm. 25 x 5 25 x 8 25 x 10 30 x 5 30 x 8 30 x 10 40 x 5 40 x 8 50 x 5 50 x 8 50 x 10 80 x 5 80 x 8 80 x 10 100 x 20 110 x 10 sqmm etc.

Ampacity of the bus bar selected must then be verified by checking table 1. Which means take a copper bus bar of 100 mm width and 10 mm thickness the area of the copper bus bar is 10 100 sqmm. Why star delta starters are preferred for higher hp motor. For example a 1 16 x 1 2 inch bus bar has an area of 0 0312 inches square and the equivalent circular area of 39 7 circular mils.