Cable circuit faults often manifest themselves in signal anomalies that interfere with nuclear power plant operation, cause problems in other equipment, produce false alarms, and cause erroneous safety system actuations. As NPPs and other industrial facilities age, identifying, locating, and mitigating degradation in safety and control systems and their associated cables is becoming a higher priority for long-term plant reliability. A cable circuit consists of three basic components: (1) a sensor or end-device, (2) cables that connect the end device to processing electronics or power source, and (3) connections such as splices, junction boxes, and structural penetrations. Any sensor that transmits small amplitude signals across long cable lengths are susceptible to noise interference and signal spiking. Electrical noise coupling into the signal cables is often the result of degradation in the cable shield or connectors. Various electrical measurements are used to identify configuration anomalies, others test the integrity of connectors and shielding, and some validate the health of the attached end device. This approach to condition assessments reduces outage time and maintenance costs, which in turn reduces the cost to the electrical utility. The focus of this paper is describing a holistic methodology for testing cables, connectors, shielding, and end devices in NPPs.