Power utilities are pursuing ways to improve the utilization and efficiency of network infrastructure, and to develop a strategic maintenance and replacement plan for their infrastructure. Underground cables require a significant time on such maintenance and replacement planning. Utilities could increase their network utilization and operation efficiency by employing the intrinsic ability of cables to tolerate emergency ratings. This ability comes from the thermal inertia of the cable system, which significantly delays the increase in cable temperature after an increase in current. This paper introduces a new network reliability evaluation coupled with cable electrothermal modelling. Thus, it captures cable system properties in combination with its surroundings (soil) conditions to allow the evaluation of cable emergency ratings within reliability assessments. This approach can help utilities to identify the critical loaded cables and provide a network-wide thermal loading map enabling more informed decisions on optimal cable maintenance and replacement.