To enable many of the normal busbar configuration inductances to be calculated for self and mutual inductances, the following formulae have been included.It should be noted that self inductance LS is the inductance due to a single conductor, assuming that it is effectively outside the flux range of all other conductors. Mutual inductance M is the inductance resulting from the flux from other conductors. Rectangular strip Single Conductor 
where Ls = self inductance, ?H Ds = 0.2235 (a + b) = g.m.d. (geometric mean distance from itself), cm l = length of busbar, cm Two Parallel Conductors 
where M = Mutual inductance, ?H Dm = g.m.d between bars l = length of busbar, cm Geometric Mean Distance Formulae Rectangular Bars 
For three Phase conductors we can write: 
