PURPOSE: To prevent a corrugated stainless steel sheath from giving a weld crack and a buckling phenomenon even when the sheath is subjected to twisting and bending stress by keeping the radius of sheath bottom within the specific ratio of a corrugation pitch.

CONSTITUTION: The radius R1 of the corrugated stainless steel sheath of a power cable is made small and taken within a range of 8% to 14% of a corrugation pitch P. In this case, when the radius R1 is less than 8% of the pitch P, a buckling phenomenon appears when the sheath is bent. And when the radius R1 exceeds 14%, twisting performance drops. On the other hand, the application of 8% to 14% of the pitch P to the radius R1 ensures freedom from a weld crack and a buckling phenomenon, thereby enabling the improvement of cable reliability.