Abstract: An optical fibre cable based on a known structure includes at least one electrical lead having an elongation on break less than or approximately equal to that of the optical fibres. This lead is inserted for example in a groove of the grooved cylinder of a cable core. The electrical lead is subject to irreversible deformation to act as a mechanical "fuse". It may be fractured in the vicinity of a crack or break in an optical fibre of the cable that has been subjected to a tensile force greater than or approximately equal to that corresponding to its elongation on break. This arrangement enables the break location in the optical fibre to be determined by measuring the capacitance between the electrical lead and a metallic member included in the cable.