Fibre optic cabling is highly reliable, but when it does fault the symptoms usually fall into a handful of predictable categories.
Common fault types
- Bend loss — the fibre has been kinked or bent tighter than its minimum radius.
- Dirty connectors — dust or fingerprint contamination on the endfaces.
- Damaged termination — a chipped ferrule or a poor splice.
- Physical break — the cable has been cut, crushed or pulled apart.
How testing narrows it down
A power meter and light source measure end-to-end loss. An OTDR sends pulses down the fibre and shows a trace with the distance to each event, which helps pinpoint where a break or high-loss point is along the run.
What test results tell you
- Whether the link is within loss budget for its length and connector count.
- Which specific end or splice is contributing high loss.
- The distance to a break, so trenching or ceiling work can be targeted.