The effect of swelling in kerosene on the electrical conductance of 60, 80, and 100 part per hundred parts of rubber by weight of Fast Extrusion Furnace (FEF) carbon black-loaded styrene-butadiene rubber (SBR, 1502) was studied. It was found that there is a characteristic time of swelling after which a sudden decrease in conductivity appears. An ideal and simple model is suggested to calculate the carbon-carbon interspacing distance, D, in the carbon/rubber matrix. The dependence of D on the swelling time is also discussed.