Abstract: The aim of research is to study the interaction between electrical tree and nonlinear barrier. The propagation of electrical tree in solid insulation is of great particular concern for power engineering industry as it is regarded as most significant mechanism for dielectric breakdown in high voltage equipment. Composite material with barriers and surrounding matrix polymers are used to extend the breakdown time of the insulation. The major influence of barriers on propagation of electrical trees is investigated in this study with experiments and software simulation. The very low conductivities of modern insulating material do not permit the dissipation of accumulated space charge and charge at the extremities of the propagating electrical tree channel. High field non-linear conductivity characteristics of SiC were employed at the barrier to influence the electrical tree growth as they impinge upon on the barrier. The electrical tree growth was greatly reduced and time to breakdown extended. The tree propagation characteristics were studied by needle plane electrode geometry with five different concentration of SiC at the barrier (5, 10, 20, 40 and 60% by weight). The results show that propagating electrical tree channels did not penetrate the barrier when SiC has high field non-linear conductivity characteristics i.e., percolation threshold >35% SiC. As a result of this phenomenon, the tree growth and barrier penetration is inhibited, leading to extended lifetime of insulation.