Force on a Current-Carrying Wire Calculator

What this tool does

This single equation is the reason electric motors turn and loudspeakers make sound: put a current in a field and the wire is pushed sideways. The force per metre is the figure that matters in busbar design, where a short-circuit current in a strong field can tear conductors off their supports.

Formula

F = B × I × L × sin θ

Variables

Worked example

Limitations

• The formula assumes ideal conditions: no friction losses, no air resistance and no efficiency losses unless you enter them.
• Electrical installations are governed by national wiring rules. Cable sizing also depends on installation method, grouping, ambient temperature and protection devices, which this calculator does not evaluate.