The paper presents the determination of circular currents in the sheaths of single-core cables during asymmetric operation. These are single-core cables arranged in a triangular bundle and with sheaths grounded at both ends. Appropriate theoretical bases of calculations are given. They are based on the current load coefficient of the cable sheath and the method of symmetrical components. The application of the respective theory is presented on examples of asymmetric loading of a cable line with a nominal voltage of 110 kV, which consists of three single-core cables of type AXLJ 1x1000/95 mm2.