US Patent 7829792 Fire-resistant safety cable provided with a single insulating covering

A fire-resistant safety cable may include at least two electrical conductors separated from each other by at least one space. The cable may include a common insulating layer surrounding the at least two electrical conductors, the common insulating layer being formed from at least one polymeric material that is adapted to be converted, at least on a surface of the at least one polymeric material, to a ceramic state at high temperatures in a fire. The cable may include an outer jacket. The outer jacket may surround the common insulating layer. The cable may have, in cross-section, at least two substantially plane faces that are substantially parallel to a plane in which axes of the at least two electrical conductors lie. A process for manufacturing the cable may include feeding the at least two electrical conductors into an extrusion head and extruding the at least one polymeric material over them.