Guidelines on earthing/grounding/bonding in the …

1 Guidelines on earthing / grounding / bonding in the oil and gas industryGUIDELINES ON earthing / grounding / bonding IN THE OIL AND GAS INDUSTRYF irst editionSeptember 2016 Published byENERGY INSTITUTE, LONDONThe Energy Institute is a professional membership body incorporated by Royal Charter 2003 Registered charity number 1097899 The Energy Institute (EI) is the chartered professional membership body for the energy industry, supporting over 23 000 individuals working in or studying energy and 250 energy companies worldwide. The EI provides learning and networking opportunities to support professional development, as well as professional recognition and technical and scientific knowledge resources on energy in all its forms and EI s purpose is to develop and disseminate knowledge, skills and good practice towards a safe, secure and sustainable energy system.

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6 7 Foreword ..81 Introduction, scope and Introduction ..9 Scope ..10 Application ..102 Functional performance requirements of earthing / grounding / bonding electrical power earthing / grounding arrangements ..14 TT TN-C TN-S systems ..16 TN-C-S (PME) systems ..16 IT (unearthed) systems ..18 Ship s systems earthing / grounding ..21 Summary of LV system supply AC substations ..22 HV/LV interfaces ..22 electrical equipment classification ..24 Static The likelihood of a strike, and risk Physical damage and life Circulating Cathodic Electromagnetic interactions between Power lines.

7 33 RF earthing / grounding / bonding interconnections as a Hazardous areas, Ex certified apparatus and ignition Earth/ground electrode resistance Touch and step voltages ..37 Temporary installations ..385 Applications ..39 electrical machines and power systems ..39 Machine sets with non-electric Ex I systems and apparatus ..41 Above ground tanks and fixed storage units ..42 Note on cathodic protection (CP) of tanks ..45 Cross-country pipelines ..45 Guidelines ON earthing / grounding / bonding IN THE OIL AND GAS INDUSTRY4 Contents continued Page Tankers and fuel transfer/dispensing Road tanker loading and unloading facilities.

8 46 Bulk railcar loading and unloading facilities ..47 Sea tanker loading Aircraft fuelling Filling Stations ..516 Detailed design/constructional requirements ..54 Field cables ..54 Protective conductors ..55 CPCs ..56 Power supply system earthing / grounding bonding Instrument and telecommunications systems, and intrinsically safe system cables ..58 Lightning protection system earth/ground conductors and down Static electricity ..58 Cable tray ..60 Earth/ground electrode Above ground floating roof storage tanks.

9 63 Steel structures (onshore) ..64 Metallic stacks and Non-metallic structures ..65 Metallic guy Operations ..66 Portable container filling ..66 Tank cleaning ..66 Scaffolding ..67 Connecting/disconnecting conductive paths ..68 Operations during lightning storms ..68 Radio silence during product Welding ..69 Tank dipping ..698 Maintenance and Permanently installed earthing / grounding / bonding Portable earthing / grounding equipment for power system maintenance ..709 Current tests (using clamp meters).

10 72 Earth/ground fault loop impedance testing ..72 Example method ..74 Measurement of Rmain see Figure 22 ..75 Measurement of R1 see Figure 24 ..75 Measurement of R1 + R2 see Figure ON earthing / grounding / bonding IN THE OIL AND GAS INDUSTRY5 Contents continued Page Determination of Rtotal see Figure 23 ..76 Completion of test Alternate methodology ..76 Existing installations (with MV transformers) where Ze is not Existing installations (without MV transformers) where Ze is not known ..77 Modifications/additions to existing installations.