Fire-resistant coaxial cables are described as well as methods to manufacture them. The
dielectric between the coax cable's central conductor and outer coaxial conductor ceramify under
high heat, such as those specified by common
fire test standards (e.g., 1850° F. / 1010° C. for two hours). The
dielectric can be composed of ceramifiable
silicone rubber, such as that having a polysiloxane matrix with inorganic flux and
refractory particles. Because thick
layers of uncured ceramifiable
silicone rubber deform under their own weight when curing, multiple thinner
layers are coated and serially cured in order to build up the required thickness. A sacrificial sheath mold is used to hold each layer of uncured ceramifiable
silicone rubber in place around the central conductor while curing. The outer conductor can be a
metal foil,
metal braid, and / or corrugated
metal. Another layer of extruded ceramifiable silicone
dielectric or an outer wrap of
ceramic fiber yarn surrounds the outer conductor and continues to insulate it from the outside if a
low smoke zero halogen jacket burns away. Methods of testing and installation are described.