3.1　General Requirements

3.1.1　Common earthing must be adopted for the earthing system of telecommunication bureaus（stations）.

3.1.2　Large-size or middle-size telecommunication bureaus（stations）must adopt TN-S or TN-CS power system.

3.1.3　Small-size telecommunication bureaus（stations），mobile telecommunication base stations and small-size stations may adopt TT power system.

3.1.4　The safety of power supply systems inside civil buildings shall be ensured for various wireless stations mounted on such buildings.

3.1.5　The design of lightning over-voltage protection shall meet the requirements stipulated in chapter 9 of this code，and the installation of SPDs shall meet the requirements of annex C of this code.