Effective quantifier elimination procedures for the reals allow to solve problems that can be encoded into corresponding first-order formulas including ordering constraints. In contrast to constraint logic programming, which is often used in similar areas, this encoding is straightforward. A quantifier elimination procedure using test point ideas is part of the package redlog by the author et al. redlog is part of reduce 3.7. We discuss how this method can be used for analysis, sizing, and error diagnosis of physical networks. The focus is on electrical networks.