Use the 3-phase power formula, rearranged for current: Example: For a 500 kW load at 400V with 0. 9 PF, the design current (Ib) is 801 A. Busbars in hot or enclosed environments can't carry as much current. The busbar sizing calculator determines the required busbar dimensions based on the continuous current rating, short circuit withstand, and thermal limits for switchgear assemblies. The current rating is calculated from the conductor cross-sectional area, material (copper or aluminium), and maximum. Quick Busbar Selector - Knowing the ampacity, designers and estimators can get the approximate bus bar size. Ampacity of the bus bar selected must then be verified by checking Table 1. For busbar sizing, the primary references are IEC 61439 (for low-voltage switchgear and controlgear assemblies) and IEC 60287 (for current-carrying. Below is a practical busbar size chart commonly used in electrical engineering applications. Enter your system's parameters (e.
[PDF Version]