In recent years carbon nanotubes (CNTs) have been widely used for the realization of polymeric matrix nanocomposites for strain monitoring applications in civil, biomedical and aerospace engineering. In fact, by embedding CNTs in an insulated polymer matrix, it is possible to realize a conductive nanocomposite with piezoresistive behaviour which allows to monitor the occurring strains through an electrical resistance change. In this work a conductive coating made of Multi-Walled Carbon Nanotubes (MWNTs) and PolymethylMethacrilate (PMMA) is fabricated and is applied onto a fiberglass structure surface. In order to characterize the electrical behaviour of the coating and its capability to sense strain, an experimental campaign is carried out by applying a voltage to the manufactured coating. Its variations throughout the surface in the longitudinal and transverse directions are then evaluated to identify the electric field distribution and its dependence on strain.