INPEX Operations Australia Pty Ltd COMPANY Doc. No. L780-AE-PHI-0003 ICHTHYS ONSHORE LNG FACILITIES JKC Doc. No. S-0780-1384-0101 Rev.1 EARTHING AND LIGHTNING PHILOSOPHY Sheet No. 9 of 13
(3) The metal framework of modules, structures, buildings and housings.
(4) Tanks and process vessels containing flammable liquid or gas.
(5) Exposed conductive materials enclosing electrical conductors, such as metallic armor and sheaths of cable, metallic shields of cable, cable ladder/trays and racks, and bus duct enclosures.
(6) The earthing strip in switchboards shall be connected via two independent earth cables.
Earthing conductors leaving the ground shall be PVC insulated and protected by rigid PVC conduit to prevent mechanical damage at the point of exit, as defined by L780-DE-DTL-0004.001 “ELECTRICAL TYPICAL INSTALLATION DETAILS EARTHING WORKS”..
Equipment fixing or anchor bolts shall not be used for Protective Earthing purposes.
3.9 Earthing Electrode for Protective Earth
Earth electrodes may consist of a number of rod sections coupled together and driven vertically into the ground. The earth rods shall be made of stainless steel (Grade 316).
Alternatively, buried copper cables, which are installed in accordance with the requirements of AS/NZS 3000 Section 5.3.6, and Section 3.10 of this document, maybe used for Process, LER, and LIR areas.
Earth electrodes shall be mainly installed in the vicinity of the substations/LER/LIR and if necessary at intervals along the earth grid to obtain a combined earthing resistance of not exceeding 1 ohm. This value is to be confirmed during detail design to ensure that earth impedance is able to generate sufficient current to cause the operation of the protection devices within the time required (AS/NZS 3000 Section 5.7.1).
The depth and size of the electrodes are to be calculated based upon measured soil resistivity values. Where required the use of Ground Enhancement Material is to be considered in order to meet the required Earth Impedance Levels.
Connections of earth grid to electrodes shall be in concrete hand holes (with removable
covers) to facilitate termination and testing.
3.10 Equipotential Bonding and Static Electricity control
General principle for bonding of various apparatus or systems to the earthing network is shown in L780-DE-DTL-0002.001 “TYPICAL EARTHING PHILOSOPHY DETAIL DRAWING”. The earthing network shall form mesh/grid type as much as possible.
Bonding network shall be meshed configuration (M) instead of star configuration (S).
Modules shall be connected to main earth grid at a minimum two Main Earth Bars located at diagonally opposite corners using 70 sqmm PVC insulated earthing cable. In order to enable testing of the connection to earth, each Main Earth bar shall be connected to main earth grid by two earthing cables. To utilize module steel structure as part of the LPS, additional earthing points shall be provided by no more than 20m interval around the base of the structure.
Process equipment i.e. storage tanks, filters, etc., shall be fitted with at least two welded lugs or bosses, which are to be connected to the main earth grid, electrode, or to an internal earth loop.
Electrical equipment mounted on package skids shall be connected to the skid structure via a