Induced currents in grounding conductors

An exception to the recommendations given in IEEE Green Book - Recommended Practice for Grounding of Industrial and Commercial Power Systems - is proposed in this paper. The exception addresses the location of the grounding conductor in cable trays, in the presence of single-conductor cables with parallel runs. It is shown in this paper the need to reach a balance between the reduction of the grounding circuit impedance and the reduction of the induced currents in the grounding conductor. An investigation carried out in an automotive manufacturing facility demonstrates that the induced ground current could become high enough to pose a safety risk. In spite of this potential risk, there are no specific rules governing the exact location of the grounding conductors on cable trays.