(For more, see electromagnetic interference). The shield minimizes capacitively coupled noise from other electrical sources. The shield must be applied across cable splices. In shielded signal cables the shield may act as the return path for the signal, or may act as screening only.High voltage power cables with solid insulation are shielded to protect the cable insulation, people and equipment.For more, see electromagnetic interference). The shield minimizes capacitively coupled noise from other electrical sources. The shield must be applied across cable splices. In shielded signal cables the shield may act as the return path for the signal, or may act as screening only.