In this article we have introduced a new approach to describe the electro-hydrodynamic (EHD) natural convection enhancement for isothermal, horizontal axisymmetric bodies, which are immersed in a liquid metal under the effects of uniform electric fields. The approach is based on a class of power series expansions introduced by Saville and Churchill for free convection in laminar boundary layers. These power series expansions have been extended to analyze the average electric Nusselt number linked to low Prandtl number fluids when the leading, and the next-to-leading, order terms are included in the approximate calculation of the temperature and the stream velocity profiles. The obtained series solutions are universal with respect to body contours. As an example, we applied this approach to calculate the average electric Nusselt numbers for horizontal circular cylinders immersed in the low Prandtl number fluids. The most important outcome of this work is that when external electric fields are applied to liquid metals the average Nusselt number may be enhanced by up to 55% of the corresponding value inherent to free convection without external electric fields. (C) 2015 Elsevier Ltd. All rights reserved.