Electrical engineering often deals with global quantities as current, magnetic flux, difference of potentials, power or torque. Previous works have shown that spectral stochastic finite element method makes it possible to spread input data uncertainties (material characteristics) to the local output which are now random. The next step consists in deriving the random global quantities from the random distribution of the fields. It has been implemented in the extended stochastic version of a 3D FEM software. The approach has been successfully validated on a 3D electrical current density problem by comparing with Monte Carlo simulation method. Finally, this method has been applied to an industrial device.