Summary: The notion of configurational force in mechanics and thermomechanics can be readily extended to electromagnetic elastic materials. By invariance arguments and through variational procedures, the Maxwell equations are transformed into a Lagrangian (or material) form and thus consistently coupled with the mechanical balance laws. In this context, the configurational forces and momenta depend also on the electromagnetic fields and specifically on the Lagrangian electromagnetic potentials. The question then arises as to whether the classical gauge conditions are still appropriate to the Lagrangian potentials. Eventually, gauge transformations for these potentials are examined for the full set of equations of interest.