Eddy current coil signals due to a crack at the edge of a right angled conductive wedge have been calculated using a boundary element scheme based on an electric field integral equation with a quarter space kernel. We consider the case in which the edge is perpendicular to plane of a crack which intersects both horizontal and vertical surfaces of the conductive wedge. The properties of the kernel mean that numerical solutions based on boundary or volume elements, can be found by using discrete approximation of the field in the domain of the flaw. Here we describe in general terms the development of a quarter space kernel for finding the quasi-static field due to a corner crack. Coil impedance variations due to the flaw have been calculated from the field and compared with experimental measurements to validate the predictions.