To mitigate the effects of magnetic induction heating in a three phase AC system, it is common practice to group the conductors and to keep them in the same raceway. Also, three phase power is generated with each phase is 120 degrees out of phase from the others. Since Three phase power is generated by a rotating assembly (generator), and each conductor has a rotating magnetic field which surrounds it along the length of the conductor, are the magnetic induction effects reduced by the action of combining the three rotating magnetic fields into a 360 degree rotating flux envelope when grouping the conductors?
The magnetic field around each individual conductor does not "rotate".
And when the three conductors are bundled together, the net current through the bundle is zero, which means that there's negligible field outside the bundle. This is why power circuits are always routed together.