BusBar Amps Calculator

Determine the current capacity of busbars

BusBar Amps Calculator

Compliant with IEC 60439 Standards (for busbar assemblies)

Results:

Cross-sectional Area (mm²): 0.00

Current Density Used (A/mm²): 0.00

Current Carrying Capacity (A): 0.00

How to Use the Calculator

Input Dimensions

  1. Enter the Width (mm) of the bus bar.
  2. Enter the Thickness (mm) of the bus bar.
  3. The calculator will compute the cross-sectional area.

Select Material

  1. Choose between "Copper" or "Aluminum" for the bus bar material.
  2. Copper has higher conductivity, allowing for greater current capacity for the same dimensions.

Set Temperature Rise Limit

  1. Select the maximum allowable temperature rise (e.g., 30°C or 50°C) above ambient.
  2. A higher temperature rise limit allows for a higher current density and thus more current.

Bus Bar Fundamentals

Bus Bar Ampacity

Ampacity refers to the maximum current a conductor can continuously carry without exceeding its temperature rating. For bus bars, this is crucial to prevent overheating and damage to insulation or adjacent components.

Factors Affecting Ampacity

  • Cross-sectional Area: Larger area means lower resistance and higher current capacity.
  • Material: Copper has better conductivity than aluminum.
  • Temperature Rise: The allowable temperature increase above ambient, influencing the current density.
  • Ventilation/Cooling: Natural convection or forced air cooling affects heat dissipation.
  • Number of Bars: Multiple bars in parallel can carry more current, but proximity effects must be considered.

Key Formula:

Current (A) = Cross-sectional Area (mm²) × Current Density (A/mm²)

Current density values used in this calculator are approximate and based on common engineering practices for natural air cooling [^2][^3].

Calculation Formulas

Cross-sectional Area (A_cs):
A_cs = Width × Thickness

Current Carrying Capacity (I):
I = A_cs × J

Where:

  • A_cs = Cross-sectional Area in square millimeters (mm²)
  • J = Current Density in Amps per square millimeter (A/mm²)

Example Calculation

Calculate current capacity for a 50mm x 6mm Copper bus bar with 30°C temperature rise:

Width: 50 mm

Thickness: 6 mm

Material: Copper

Temp Rise: 30°C

1. Calculate Cross-sectional Area:

Area = 50 mm × 6 mm = 300 mm²

2. Determine Current Density (Copper, 30°C):

Current Density (J) = 1.4 A/mm²

3. Calculate Current Carrying Capacity:

Current (I) = 300 mm² × 1.4 A/mm² = 420 A

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