In order to accurately analyze the earthing switch failure causes in windy weather, through the onsite inspection, action process analysis, material analysis of structural parts and the stress condition analysis, this paper confirms that the failure reason of the abnormal closing of this earthing switch is the loosened bolt caused by the unreasonable size design of the crank arm bolt and the unqualified material. Furthermore, the targeted validation tests and preventive measures are carried out to ensure the safe operation of the equipment.
