The article shows that a steady tendency toward reduction in the polarization shielding potential of underground metallic constructions (UMCs) is observed with an increase in soil resistivity and defect sizes. It is noted, that this phenomenon presents the most danger in zones with the lowest shielding polarization potential (determined in accordance with the requirements of the GOST 9.602 – 2005 standard). We have described athe complex of measures, aimed at decreasing the potential risks of insufficient cathodic protection of UMCs, among which it is worth mentioning the following: constantly monitoring the state of UMC isolation both during construction and in operation, with the focus of attention on zones with increased soil resistivity, and immediate repairs carried out, in case any isolation flaws are detected; positioning the drainage point of the shielding current in the conduit, if it is possible to do so in zones with increased soil resistivity and reduced isolation quality.