The helical suspension clamp is widely used in terms of structure performance

energy conservation. The failure helical suspension clamp in a ± 800 k V transmission line was investigated by means of material property testing

mechanical strength test and mechanical calculation. It was found that the suspension angle of the clamp is 10 degrees

which do not conform to the requirements of the DL/T 763—2013. The tension tests indicated that the ultimate strength of the clamp is about38 k N while the outlet angle is 40 degrees. When the clamp’s suspension angle is a constant value

the greater the outlet angle of clamp

the smaller its ultimate strength. The dynamic response of ice shedding-caused vibration was analyzed by finite element method（ FEM）. The results showed that when ice shedding occurs on 80% and above length of the front span groundwire

the outlet angle of back clamp will increase

and the corresponding tension of ground wire would reach the ultimate strength of clamp. It was pointed out that clamp’s fracture is the result of the ice shedding and its small suspension angle. It was suggested that the deformation inspection of helical suspension clamp should be carried out in heavy icing area.