Protect bolted connections against corrosion either hy filling with vaseline or coating with a special anti-corrosion compound and proper capping (Denso tape / grease caps).
Comply with the General Conditions, Supplementary Conditions and the requirements in various Sections of the Electrical Specification. In addition read and conform to all Electrical Sections of these specifications. The installation shall comprise air networks connected to roof and down conductors and finally terminated in earth electrodes, via structural re-bars and suitable test points in accordance with the details included on the attached drawings or in the Specification Section.
The metallic sheath and armour of multicore cables shall be bonded together and earthed.
Cable earthing conductors shall be copper strip with appropriate section laid in formed cable trenches or ducts, or fixed to walls, concrete or steel work, by means of clamps or claw type cleats, appropriately secured into suitable wall plugs or tapped holes. The spacing of fixings shall not be greater than 1 m. Where earth strip is buried or laid in positions in which there is danger of corrosion it shall be provided with a corrosion-proof serving of extruded thermo-plastic or self-adhesive PVC tape which for short lengths may be hand applied on Site.
Continuity: Ensure that complete earthing system is electrically continuous and mechanically secure. Locations of main earth bars in substations, electrical rooms, mechanical rooms, hub (Technical) rooms, etc., to be clearly identified by 100mm X 100mm white traffolyte labels, with red lettering, to Engineer's approval.
Main earthing bar is to be provided in main distribution room and connected to earth electrode by 2 insulated conductors (minimum 150 mm2) via testing joints. Earthing bars of main distribution boards are to be connected, by insulated earthing conductor, directly to main earthing bar at main distribution room.
Compound Demarcation or separations of compounds may use metallic fences sometimes for saving money or aesthetic reasons. Architects and owner of the project decide whether their property protected by compound wall or it needs only fencing. If fencing considered, most cases it will be metallic fence. In the electrical point of view and as a safety measure, metallic fence shall be separately earthed unless they come within 1.8 m of any equipment or structure above the surface of the ground, which is connected to the main earthing system. If the separation of 1.8 m cannot be obtained the fence shall be bonded to the earthing system. Here is how compound fences connecting to the earthing system.
PVC insulated copper strip conductors or PVC insulated stranded copper cables with cross-section min 70 mm2 or as per earthing calculation.
PVC insulated copper conductor as described in the Specification for the particular application.
Clean earth grounding or low noise earth shall be provided as required, to ensure that the level of induced or conducted interference from external sources, including the facility power grounding system, does not produce incidence of malfunction of the equipment, which is unacceptable for the operating system. The electronics systems must be protected by providing a network path having low impedance for interconnecting its equipment.
Proper routing, zoning and shielding of the cables / earth wires are important and must serve the purpose of preventing sources of electrical disturbances from the operation of electrical equipment.
Earthing or Grounding Electrode for an effective and reliable electrical earthing system requires proper survey and analysis of project location, type of structures installed and electrical / electronic equipment used in the entire system. The design calculation of the earth electrode systems shall be based on the approved earth resistivity data and the system's fault currents and their duration.
Earthing / Grounding work has to comply with the requirements of General and Technical Conditions of the Project including statutory obligations and regulations. Submittals to be approved by project consultant prior execution of the actual work. Regulations and rules of supply authority also to be considered when preparing the submittals for the local in which installation is being constructed.