Percolating carbon conduction network is not only a long-time pursued scientific topic but also becomes more and more technologically important. Yet no established diagnostic tool is available. A simple two-wire transmission line (TL) model with symmetric boundary condition is suggested as working equivalent circuit model for the percolating carbon network in the insulating matrix such as polymer materials. Spatially distributed shunt capacitors of TL network are determined by the spacing between percolating backbone pathways of resistors. Deviation from the ideal RC TL behavior of the real network due to the non-uniform geometry, dangling network, random distribution of carbon fillers between the backbone pathways, etc. can be represented by modified yet parametric TL models featured by the generalization of the shunt capacitors to constant phase elements. (C) 2012 Elsevier Ltd. All rights reserved.