the magnetic field generated by the coupling transformer can impinge upon nearby traces and cables, and the parasitic capacitance between the primary and the secondary acts as a bypass for any CM noise.

Conversions along the network
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PLNs are characterized by many sources of unbalance, since many are the devices that constitute the network: power cables, junction boxes, power strips, plugs, sockets and the devices therein branched. Some of the common mechanisms giving rise to mode conversion have already been analyzed in the literature [@1629710; @Arteche:722106; @trcvel14055] and we present them below.

### Conversion to common mode along the line

A typical power line cable, in both longitudinal and transverse directions, is far from being regular and uniform. Differences in the dielectric material thickness, radius of the copper conductor, relative position of the cables, are usual in this type of network. Also simple cable bends can perturb the symmetry of a line. Each of these discontinuities results in a localized variation of the cable electrical characteristics, which produces mode conversion.

Moreover, inside junction boxes, power strips, plugs and sockets, the three conductors of a power line are generally unwrapped from the outer sheath. The different conductors are then differently 