To prevent thunder failures generated in a user terminal and the like via a reinforcement line of an optical fiber at the time of thunder stroke with ease and with certainty.
Optical communication facilities have: an installed supporting line 1; an optical fiber line 3 arranged in parallel to the supporting line 1 and communicating information; a reinforcement line 4 for reinforcement of the optical fiber line 3; and a plurality of hanger lines 2 for hanging the optical fiber line 3 from the supporting line 1 to support the optical fiber line 3. The reinforcement line 4 has one end directly grounded and the other end grounded via a capacitor 5. In the plurality of hanger lines 2, the hanger lines 2 adjacent to each other are connected via a capacitor 6 to form a long connection hanger line 7. The connection hanger line 7 has one end directly grounded and the other end grounded via a capacitor 8. Thereby, at the time of thunder stroke, each of the reinforcement line 4 and the connection hanger line 7 is grounded equivalently at both ends, and a closed circuit via the ground is formed to make mutual induction act between the reinforcement line 4 and the connection hanger line 7 and to generate parallel resonance at the reinforcement line 4.
HIGUCHI HIROBUMI
TOSHIN ELECTRIC
Tsuyoshi Kumano
Shinichi Tomohiro