I am a low voltage installer, and have encountered an install on the roof of a commercial building for a network radio that communicates with another building downtown. Per the NEC the radios and the lightning arrestors associated with them need to be properly grounded. Section 800 says the length shall not be more than 20ft and if more than 20ft install another ground rod and bond to the electrical system with not less than a #6 ground wire. This being a roof I can't install a ground rod obviously, but can a roof tie off point like in the picture below be used as a connection to building steel and would I still need to bond with a #6 to an electrical ground in the building? My only pathway is the conduit for the low voltage cables, and per the NEC you should maintain at least 6ft of separation from the communications cables. Also, where PVC pipe is installed on the roof for the purposes of physical protection and attachment of cabling, is it a requirement to glue all fittings if the cabling is outdoor rated?