Reliability and dependability challenges within the aerospace, military and civil aviation industries are driving the need for advances in health and usage monitoring technology. One promising method with the potential to complement conventional inspection and electrical test techniques for wiring is acoustic methods. In this paper modelling and experimental results for acoustic signal propagation in various wire systems is reported that includes methods for locating mechanical, electrical and thermal discontinuities in wiring. Simulation results for the pulse echo mode of propagation has provided us a new perspective on the sensitivity achievable. Experimental results support these conclusions. An optimization of the acoustic mode of propagation in a wire by using shear longitudinal and shear transverse excitation are also discussed.(12)