14.2　General Items

14.2.1　The span line in mine is semi-fixed.Usually wooden pole is used with the setting depth of 1-1.5m.At least 1 pole is used for each bench and it shall be at least 5m from the edge of mining bench.

14.2.2　The height above ground of the wire at bottom layer of distribution line for open pit mine shall be:

1　Not less than 5.5m for circle line.

2　Not less than 6.5m for span line.

3　Not less than 5.5m for longitudinal line.

4　The point where the line crisscross spans shall be in accordance with those specified in Item 3 of Article 13.2.8 of this code.

14.2.3　For span line，the length of cable on the high-voltage side of mobile electrical substation should not be more than 100m，and the length of cable for mobile electrical shovel should not be more than 250m.

14.2.4　For longitudinal line，the length of cable on the high-voltage side of mobile electrical substation should not be more than 50m，and the length of cable for mobile electrical shovel should not be more than 200m.

14.2.5　The surface of high-voltage porcelain component must not have defects like crack，damage and burned enamel.Porcelain cross arm shall not be used for the lines in mine.

14.2.6　The wire must be securely connected，and the joint must be free from broken strands and damage.The connecting pipe for the wire must be free from cracks after compression joint.