NYM-J & NYM-O BVV Multi-core Copper Wire PVC Insulated PVC Sheath Electric Wire and Cables. The NYM Cable is for fixed wiring, available as NYM-J (with green/yellow core) and NYM-O (without green/yellow - part numbers with an -O as a suffix). As with many fixed wiring cables, it has a Class 1 solid or Class 2 stranded copper conductor. Available as a single core or in multicore variants, it is readily available in configurations up to 12 cores. Frequently specified in building and construction projects across Europe, it is used in both domestic, commercial and industrial applications and can be installed directly into concrete.