a cable rack arm and support system suitable for underground power and communication service is made from a non - metallic polymer that will not rust or corrode . the cable rack arm is adapted for mounting to existing underground stanchions or for stanchions of a more modern design . each cable rack arm is securely mounted to the stanchion . each cable rack arm then supports one or more cables in cable rests or saddles molded atop the arm , thus keeping the cables accessibly organized in a manhole , tunnel or vault . plastic cable ties may be used to secure the cables to the cable rack arms . nonmetallic pins may also be used to secure the cable rack arms to the stanchions . the stanchions may be made of nonmetallic composite material that includes a fiberglass cross - layered knitted apertured mat for increased strength .