In the construction of power cables, steel brackets are used, steel protection tubes are used, and cable cards and overhead cables are used. Any galvanic (iron) closed loop is formed around the power cable, and eddy currents may form. Especially in high current power cable systems, eddy currents are greater. Once there was a section of a 10 kV overhead cable of about 0.4km. The steel strand was used as an overhead support. The post and cable used cable clamps to fix the cable. A ground fault occurred shortly after the commissioning. After inspection, the cable clamp and the strand were closed. The eddy current circuit burns the cable insulation after heating, causing a ground fault. After analysis and testing, after the cable clamp and the stranded wire are separated by an insulation layer (such as a stripped cable insulation sheath), there is no eddy current phenomenon, and the operation will be normal for many years without similar failure. It can be seen that in the construction of power cables, measures must be taken to prevent the formation of steel (iron) closed loops around the cables to prevent eddy currents from occurring.