3.11　The Earthing of Centralized Monitoring System and the Interface Protection

3.11.1　At middle keraunic zones or above，the monitoring equipment with higher surge immunity and endurance capacity shall be adopted.

3.11.2　Within the scope of telecommunication bureaus（stations），overhead lines must not be used in the outdoor environment.

3.11.3　The interface of the key equipments required for lightning protection shall be equipped with corresponding SPDs.

3.11.4　Laying of monitoring cables and trunkings shall not be close to columns or beams of buildings.In case inevitable，the laying length along columns or beams shall be as less as possible.

3.11.5　Laying of various cables shall be far away from structures possibly suffering from direct lightning flash，such as telecommunication towers and so on.Such cables shall not be laid along the corners of buildings.

3.11.6　Laying of various indoor monitoring cables should be gathered at the middle part of buildings.

3.11.7　Various monitoring cables should be shielded cables or run through metal conduits.

3.11.8　Two ends of cable shielding layers，shielding casing pipes or shielding trenches and the like shall be earthed.

3.11.9　The cable shielding layers shall maintain whole-course electric connection.Multipoint earthing in the vicinity should be adopted.And shield connectors and junctions shall be well connected；meanwhile the shields shall be well earthed.