ABB REL650 - Line Distance Protection REL650 2.2 IEC Commissioning Manual; Checking Optical Connections

4.11 Checking optical connections
M16022-2 v7
Check that the Tx and Rx optical connections are correct.
An IED equipped with optical connections has an minimum space
requirement of 180 mm for plastic fiber cables and 275 mm for
glass fiber cables. Check the allowed minimum bending radius
from the optical cable manufacturer.
Section 4 1MRK 506 383-UEN A
Starting up
44 Line distance protection REL650 2.2 IEC
Commissioning manual