P = coefficient given in Table 5 for Two lengths at 90° electrode arrangement =4 Q = coefficient given in Table 5 for Two lengths at 90° electrode arrangement = 0.9 Then, the resistance R for the round conductor electrode = 0.206 ohm. W = diameter of 240 mm2 bare copper conductor Earth round conductor electrode: For the round conductor electrode the resistance R, in ohms is given by the following equation: Then, The combined resistance of all earth rod electrodes in parallel Rn =0.394 ohm.Ĭ. So, n = 7 and s = 41 m R = earthing resistivity for one earthing rod The total number of electrodes around the rectangle = 24 rods each of the length of 9.6 m. Ρ = wet Soil resistivity (according to the design report) Then, R = 2.486 ohm for one earthing rod.
L = Effective Length of the electrode exist in the wet soil = 4.2 m d =Diameter of the earthing rod So the effective length of the electrode rod through the wet soil (10 ohm.m resistivity) will be =4.2 m, where the total length of electrode rod 3*2.4 = 7.2 m. Load Centre A - Structural floor level is 7m above MSL with the design water table level at 4m above MSL, this level is based on recommendations of HUTA and is subject to final confirmation by them. Earth electrode rods: The resistance to earth of a rod or pipe electrode R, in ohms, is given by the following equation: Current Density at Surface of Earth Electrode.ī.Combined earth resistance interconnection of the MV and LV networks. Length of Earth round conductor electrode. Number of earth electrode rods per each loop. All the formulas and tables are copied from BS 7430:1998 and BS 7354:1990 This study is to be used to aid in specifying the following: Įarth electrode rod length.
#Bs 7430 earthing calculation code
Purpose/Scope The purpose of this report to obtain the MV&LV earthing calculation study for load centre A of KAIA project according to BS Code books (BS 7430:1998), (BS 7354:1990) and the design report. 15Ĭurrent Density at Surface of Earth Electrode.
12Ĭalculation of Touch and Step Potentials. 10Įarth rod with round conductor electrodes combination earthing network.
0 kommentar(er)
