In power engineering the eddy current approximation of the Maxwell equations has been widely used. For a class of problems with low 
penetration depth the behaviour of the electromagnetic fields inside a conductor can approximately be described by impedance boundary conditions, making the problem an exterior one. Then by using a formulation in the magnetic field the whole problem becomes scalar. It is shown how the problem reduces to a hypersingular boundary integral equation with a nonsymmetric, strongly elliptic associated operator. The problem is discretised by a Galerkin BEM. An example is given.

* Research of this author is supported by the ABB Corporate Research Center Heidelberg, Germany.