Summary: A. Bejan’s constructal theory [Shape and Structure, from Engineering to Nature, Cambridge University Press, Cambridge (2000; Zbl 0983.74002)] is explored for a paradigm problem in electrical theory, analogue of a wide range of transport problems involving flow subject to a Ohm’s Law model. The equi-potential optimisation is derived and generalised to further functional behaviour of resistances. The original case illustrates the power of Bejan’s asymptotic-intersection method.