 This paper proposes an equation to estimate Lorenz number, L, which is used to calculate the electronic component of thermal conductivity, Kappa E. The equation takes into account the measured thermal power, S, and can be used for non-degenerate semiconductors where L deviates significantly from the degenerate limit. The proposed equation is accurate within 5% for single parabolic band slash acoustic phonon scattering assumption and within 20% for PbC, PbS, PbT, C0.8 to 0.2. Using this equation instead of a constant value will significantly improve the estimation of lattice thermal conductivity when detailed band structure and scattering mechanism is not known. This article was authored by Hyunsik Kim, Sakri M. Gibbs, Englutang, and others. We are article.tv, links in the description below.