Numerical modeling of electromagnetic nondestructive testing problems has become in the last few years common enough to be considered an integral part of the engineering design practice. In particular, eddy current modeling activity has been on the increase because of the benefits afforded by such models and their relative simplicity and availability. This is certainly true for two dimensional and axisymmetric modeling where both general [1] and NDT models [2] exist. In many such cases, little more than a small computer and a reasonably trained person are needed.Three-dimensional models for general field problems and for NDT applications present a totally different situation. The formulation of Maxwell's equations is in itself more complex and the type of formulation has important implications. Formulations rang ing from single and double scalar potentials [3] through magnetic vector potentials [4] to combinations of scalar and vector potentials [5] abound. Far more significant than the choice available is the fact that these formulations are not necessarily equivalent and their applicability is not universal.