The thermal state at a solid-solid contact with interfacial heat generation requires the knowledge of two macroscopic contact parameters: the thermal contact resistance (R-TC) and the heat generation factor (alpha). R-TC is already well defined by many theoretical models, on the other hand, alpha remains poorly known and was never studied in the case of electrothermal contact. On the basis of a microscopic analysis of the coupled electrical and thermal phenomena in a current tube crossing two asperities in contact, we propose a model of the heat generation factor. This one is a combination of electrical resistivities and thermal conductivities of both materials in contact. Comparison of model to experimental data are presented and discussed. (c) 2005 Elsevier Ltd. All rights reserved.