This paper presents a new measurement method that enables investigating the degradations of protection networks under cumulative ESD pulses. The setup is based on a Transmission Line Pulse (TLP) combined with Time Domain Reflectometry (TDR) to get access to the complex impedance of the device under test. One of the advantages of the technique is that the frequency behaviour of the DUT is extracted as the same time the device is aged. The method is validated on a stable component and different devices are tested. Results show that after a certain number of pulses, the characteristic of the device have changed significantly. The extracted impedances can then be used into system design flow to investigate the impact of ESD stresses on sustainability of ESD protection network. Observations on the deviations of these input protection networks could also have impact on the electromagnetic immunity networks.