Grounding system notes
1. Unless otherwise noted, PVC insulated ground wire shall be used for grounding circuit.
2. Grounding wire shall be installed a minimum of 600mm below finished grade.
3. Abovegound connections shall be made using rigid clamp type ground connectors and bolts.
4. Ground rods shall be copperclad steel, 18mm diameter, and a minimum of 2400mm long.
5. Locations of ground rods are approximate, where rods are grouped , place rods a minimum of 3m apart.
6. Provide conduit protection for ground cable where it emerges from ground, ream ends of conduit to remove any burrs.
7. Wherever conduits terminate at cable tray, use grounding bushing and make connection to the main ground loop.
8. All equipment and structure grounding connections are to be painted with corrosive resisting paint immediately after installation.
9. Minimum grounding cable and protective conduit size shall be as follows, unless otherwise noted.
-main grouding loop:120mm2
- taps to electrical equipment in substations as switch gear, MCC etc. :70mm2
- taps to motors
A. Low voltage moter
Up to 11.25KW: 10mm2
Up to 22.5KW: 16mm2
Up to 40KW :35mm2
Up to 70KW :70mm2
Up to 90KW :120mm2
110KW to 150KW : 185mm2
B. High voltage motor : 50mm2
-Taps to transformer neutral :150mm2
-Taps to power/lighting panelboards: 25mm2
-Taps to local control panel :25mm2
-Taps to welding receptacles :25mm2
-Taps to pushbutton station :6mm2
-Taps to pipe rack :25mm2
-Taps to process equipment for static grounding :25mm2
-Taps to structure grounding for lightning protection :95mm2
10. Steel structures and similar installations shall be grounded at every 30m(at least two points per structure) including pipe rack.
11. Tank, vessels and steel towers shall be grounded at least two points per tan or vessel.
12. The main ground loop shall be provided with ground wells including testing rod at strategic locations for testing purpose.
13. Ground for utility equipment shall be connected main grounding wire in cable tray