Always roll the cable off the spool instead of spinning it off the spool end. Make sure your fiber cable is long enough for the run. This damage can take several forms, including micro-bending, macro-bending, and stress-induced attenuation. Unshielded Twisted Pair Cable: Cables without shields are called. Imagine what happens when you twist a piece of wire, and compare that to what happens if you twist a piece of glass. It's probably obvious that the glass fiber is more fragile, and should be treated with more care. It can occur during installation, handling, or operation of the cable.