## 7 Conclusions  
The soil resistivity value is a key requirement for GS designs. Although some tables of the relationship between the type of soil and its resistivity, geological maps and graphs from which general resistivity ranges can be determined are available in the literature, the resistivity must be measured in the location where the components of a GS are to be installed. LRMs were installed in each of the vertical rods of the designs studied here (see Figure 4) to assess how they affected the GR as a function of both the GS design and the ground resistivity. Premixed and dry LRMs were used, considering the variations in costs, building methods and compactness. The GR of the LRMs was measured using the three aforementioned methods 28 days after installation due to the contact between the rods (including the LRM) and the ground. The results show that the GR of the LRM markedly decreased in the high-resistivity soils. Conversely, in the low-resistivity soils, no significant changes occurred. Similarly, the LRMs showed a better effect for the simple GS designs, such as the one-rod (1R) design, than for the complex GS designs, such as the rectangular grid of six vertical rods (6 RR) (see Table 11). This article presents the most important results from the experimental plots in eight locations, each of which contained several GS designs with LRMs in both low- (such as S1 with a resistivity of 24 \(\Omega\cdot\)m), and high-resistivity (such as S8 with a resistivity of 302 \(\Omega\cdot\)m) soils. Practical aspects of the application of standard procedures in GS engineering are presented: application of the Wenner method, soil interpretation using the results from the Wenner method, GR calculation of the designed GSs and GR measurements. Experimental studies on the effects of LRMs are generally based on laboratory and/or small-scale tests. The main findings of this study, which was based on a combination of calculations and measurements and the use of LRMs, are presented in Table 12. This table outlines the percentage values of the reduction in the GR when the LRMs were used compared to the original values. These percentages varied for the GS design and the ground resistivity. Through the formulation of Section 3.4, the GR can be calculated by modifying the different variables involved, and later, depending on the design chosen, apply the reduction percentage when LRM is applied to the vertical rods. Thus obtaining the calculation and design of the grounding mesh with LRM; the higher the resistivity, the greater the number of rods and conductor wire can be reduced. Although it is true that Table 12 is limited to 250 \(\Omega\cdot\)m, the study can be extended to soils with higher resistivity, achieving a greater percentage reduction in GR, and above all relating the grounding configurations land with the theoretical calculation. Likewise, additional studies could be carried out by implementing LRM in the conductor cable buried horizontally, taking into account that this would require significant financing. The entire study was conducted following guidelines and recommendations, primarily IEEE standard 80-2013 [3] and IEEE standard 81-2012 [26]. Electrical engineers, electricians, researchers, and people associated with the area of earth leakage protection can easily use the results from this study to design GSs according to the required GR, either using common materials or LRMs. Conceptualization, A.B.-E.; Data curation, A.B.-E. and F.Q.-P.; Funding acquisition, A.B.-E. and F.Q.-P.; Investigation, F.S.-S.; Methodology, F.S.-S. and C.C.-N.; Project administration, A.B.-E.; Resources, F.Q.-P.; Software, F.S.-S. and C.C.-N.; Supervision, A.B.-E.; Validation, F.S.-S. and C.C.-N.; Visualization, F.Q.-P.; Writing--original draft, F.S.-S.; Writing--review & editing, A.B.-E. All authors have read and agreed to the published version of the manuscript. This research was funded by the Energy Research Group (GIE) of the Salesian Polytechnic University, Cuenca, Ecuador under resolution N\({}^{\circ}\) 003-005-2019-07-18.