An overhead electric conductor comprises a central tubular metal core, at least one layer of helically wound bare metal wires surrounding the core and, loosely housed in the bore of the core, at least one optical fibre element. The optical fibre element comprises a flexible tube of elongate transverse cross-section in which is loosely housed an optical fibre ribbon structure and which is resiliently set in such a form that it follows a path of smoothly curved undulations, the axes of curvature of which lie parallel to one another and normal to the axis of the tube. Should a tensile force applied to the overhead conductor be transferred to the loosely housed optical fibre element, the flexible tube of the element will tend to straighten in a lengthwise direction against the action of its resilient set thereby to reduce any tensile force that might otherwise be applied to the optical fibres and, when the tensile force is removed, the tube will return under the action of its resilient set towards its original form.