ENA ER S34 : ISSUE 1 AMD 2 1988

1 INTRODUCTION
2 SCOPE
3 SYMBOLS AND DESCRIPTIONS OF SYSTEMS
4 ESTIMATION OF THE RESISTANCE OF
  INDIVIDUAL EARTH ELECTRODES AND
  THE IMPEDANCE OF INTEGRATED
  EARTHING SYSTEM
5 THE DISTRIBUTION OF EARTH-FAULT
  CURRENT IN RELATION TO RISE OF
  EARTH POTENTIAL
6 TECHNIQUES FOR ASSESSING RISE OF
  EARTH POTENTIAL
7 ESTIMATION OF THE ZONE OF RISE OF
  EARTH POTENTIAL IN RELATION TO
  LIMITS CONCERNING ELECTRICAL INTERFERENCE
8 EXAMPLES OF PRACTICAL CALCULATIONS
APPENDIX A: MEASUREMENT OF SOIL RESISTIVITY
APPENDIX B: FORMULAE FOR DETERMINING THE
            PROPORTION OF CURRENT RETURNING IN
            THE GROUND FOR EARTH-FAULTS ON POWER
            CABLES WITH METALLIC SHEATHS EARTHED
            AT THEIR TERMINAL ENDS
APPENDIX C: THE DETERMINATION OF CCITT
            VOLTAGE LIMIT CONTOURS FOR SUBSTATIONS
APPENDIX D: REFERENCES

Specifies methods which should be used to assess the maximum rise of earth potential and the local ground potential which can occur at transmission, grid supply points and primary and distribution substations operating at 6.6 kV and above. It also prescribes methods for determining the value of the resistance/impedance of earth electrode systems. It may be used in conjunction with Technical Specification 41-24 (Guidelines for the design, installation, test and maintenance of main earthing systems in substations) which recently replaced Engineering Recommendation S5/1 (Earthing installations in substations).