3.4　Earthing Connection

3.4.1　Earthing connection shall be anti-corrosion treated.

3.4.2　40mm×4mm or 50mm×5mm hot dip galvanized steel flats or multistrand copper wires with a sectional area not less than 95mm2 and a length not exceeding 30m should be adopted for earthing connection.

3.4.3　Earthing connection should not be laid together with heating pipes in the same trench.The connections being laid shall keep far away from sewage pipes and gutterway.For the portions out of the earth，protective measures to prevent mechanical damage shall be taken and insulation and anticorrosion treatments shall be performed.

3.4.4　The earthing connection connected with the main earthing conductor shall be led in from two sides of the earth grid nearby.

3.4.5　The multistrand copper wires with a sectional area not less than 240mm2 shall be adopted for the earthing connection between the earth grid of the high-rise telecommunication building and the vertical riser，which shall be led in from two different directions of the earth grid.

3.4.6　The earthing connection shall not be led in from the vicinity of the pillar of the lightning downconductor system.

3.4.7　The pillar rebars being used as earthing points at buildings shall be rebars that are wholly welded and connected.