All insulations shall be a moisture- and heat-resistant type carrying a temperature rating of 90°C (194°F). 2* All conductors for underground trainways or stations, except radio antennas, train control (signaling). rial environments. The cable is suitable for both indoor and ou door installation. The outer sheath is made from black UV-stabilized and weather resistant material which is SHF1 classified, and may be exposed for shorter periods to fluids such as diese and mineral oils. In addition, also with water spray and. Corning Optical Communications manufactures quality flame retardant optical fiber cables for indoor applications, which comply with the requirements of the National Electric Code® (NEC® 2023) published by the National Fire Protection Agency (NFPA). Applications for approval or extension of approval submitted after February 22, 1994 shall meet the requirements of this subpart. The. (1) Only Rural Utilities Service (RUS) accepted filled cable and splicing materials shall be used on outside plant projects financed by RUS.