The Physics

Exact AC Voltage Drop

DC formulas ($V = IR$) are strictly for direct current. In modern AC systems, we must account for the changing magnetic fields and alternating flow.

Effective Impedance ($Z_eff$)

In AC circuits, resistance ($R$) is only half the story. We also have reactance ($X_L$), which is the opposition to current flow caused by inductance.

Impedance combines both vectors. This result gets more noticeable as wire size increases, because larger wires have more self-inductance ("Skin Effect").

Power Factor Matters

The Power Factor ($PF$) of your load determines how much the current lags behind the voltage. A lower PF increases the effective voltage drop.

Standard calculators often ignore PF or assume it is 1.0 (unity). ConduitLab allows you to specify the PF for exact results.

Raceway Type

Steel conduit (magnetic) increases the inductance of the circuit compared to PVC or Aluminum (non-magnetic). This physics phenomenon is accounted for in our AC calculation method.