Concentricobjects share the same center, axis or origin with one inside the other. Circles, tubes, cylindrical shafts, disks, and spheres may be concentric to one another. Concentric objects do not necessarily have the same radius.
Concentric circles
Concentriccable is a cable type used in TN-C-Searthing systems where the combined neutral and earth core completely surrounds the live core(s). This minimises the risk of completely cutting through the combined neutral and earth without first completely cutting through the live cores.