Maximum Circuit Length Calculator

*The following calculator is for reference only.

$$ L_{\max}\ =\frac{0.8U_{\circ}S_{ph}S_{pe}}{I_aρ(S_{ph}+S_{pe})} $$
Uo , nominal phase volts (230 V)

\( \rho \)

, resistivity at normal working temperature, in

\( \Omega \)

(22.5 x 10-3 for copper, 36 x 10-3 for aluminium)
Circuit breaker size(A)
Select Circuit breaker type : Type B, Type C, Type D
I(rated current)*


= Ia , trip current setting for the instantaneous operation of a circuit breaker or the current that assures operation of the protective fuse concerned, in the specified time
Sph , cross-sectional area of the active conductor of the circuit concerned, in mm2
Spe , cross-sectional area of the protective earthing conductor concerned, in mm2
Lmax , maximum route length, in meters