16. Fibre Rating NEC – National Electrical Code – for all Premises cables Low Smoke Density OFN-LS Plenum rated for use in air handling plenums OFNP or OFCP Riser Rated for vertical runs OFNR or OFCR General Purpose OFNG or OFCG Optical Fibre Conductive OFC Optical Fibre Non-conductive OFN Description NEC Rating