Currently, the operation of modern industrial processes depends on many different components (systems and plant devices) all of which are tied together through communication systems. In large-scale systems, due to the difficulty of monitoring the communication infrastructure, the latter is vulnerable to external physical intervention, which could have, as a consequence, the loss of communication among process components. In some cases, to avoid loss of communication, redundancies or alternative paths are implemented, but this is not necessarily the most efficient solution. In this paper, a fault diagnosis approach based on structural analysis that makes effective use of its infrastructure in a communication-loss condition is proposed. This is accomplished by considering the communication structure in the proposed approach to apply optimization methods guaranteeing optimal use of the available communication structure. For this, diagnosers choose the best communication paths or, if necessary, change their design. The proposed approach is applied to a power distribution system achieving diagnosis goals in a communication-loss condition.