  Potential equivalence transformations (PETs) are effectively applied to a
class of nonlinear diffusion-convection equations. For this class all possible
potential symmetries are classified and a theorem on connection of them with
point ones via PETs is also proved. It is shown that the known non-local
transformations between equations under consideration are nothing but PETs.
Action of PETs on sets of exact solutions of a fast diffusion equation is
investigated.
