This paper analyses reliability metrics against surges affecting insulation of " Cable -Submersible Electric Motor" system of electric submersible pump equipment. The paper contains assessment methods of reliability metrics based on statistical laws superposition of mean time between failures (MTBF) of the "Cable - Submersible Electric Motor" system elements, and of estimation of insulation resource consumption of submersible electric motor against surges. Submersible Electric Motor (SEM) resource consumption calculation is included. Calculation results are presented in the form of electric motor survival probability dynamic pattern as a function of resource consumption. Actions to protect submersible electric motors against surges are offered.