Recently, the world is witnessing a vast daily development in technology accompanied with more and more complex electronic systems. They are hosting cumulated lengths of electrical cables that are subject one day or another to the occurrence of wiring faults. Accordingly, wire diagnosis became essentially important for ensuring safety, security, integrity and optimal performance. On the other hand, the emergence of sensor networks and connected objects have created the need for embedded and non invasive fault diagnosis solutions. Notably, multi-carrier reflectometry methods have shown promising and efficient results in locating upcoming defects on wires in an online manner. Nevertheless, their precision stays within the physical limits of their components, especially the sampling frequency of their analog/digital transitions. In this paper, we will propose several approaches combining multi-carrier reflectometry with phase analysis techniques to overcome this limit. Accordingly, an improvement in the precision of the fault localization and a high spatial resolution is obtained. Based on an FPGA implementation, our novel methods and the resulting systems have proven a fivetimes better accuracy than state-of-the-art methods on the same platform.