(1) Separately set a ground lead wire of the iron core clamp. Because if the iron core touches the upper clamp to cause a multi-point ground fault, the ground current only flows inside the iron core clamp, and no current flows through the core ground lead, which will cause the staff to mistakenly believe that the iron core has not failed; After setting, no matter where the iron core touches the clamp, it will form a loop through two grounding external leads, so that the grounding current can be correctly detected externally.
(2) The core grounding piece is placed in the middle of the cross section of the iron yoke. Placed in this way, no matter where the iron yoke pulls the insulated bolts and where the fault ground point is, the maximum induced voltage of the loop is only 1/4 of the turn voltage, and the maximum ground current at this time is only a few amperes, which is more The grounding lugs are much smaller when placed in other locations.
(3) If it is indeed necessary to place the iron core grounding plate at another location due to inconveniences such as on-site installation, the insulation bolts of the iron yoke strap and the grounding plate should also be placed diagonally to prevent large currents.