Measurements and studies developed to mitigate harmonic and flicker emission to public networks are presented in this paper. Two different real cases are analyzed. The first one is a new electric furnace with low power factor, which is added to the load consisting of other existing furnaces. The installation had a reactive compensation bank which, according to measurements and studies, would cause harmonic resonance with weak public networks. As technical solution, a dumped C-type filter was designed, taking advantage of the existing bank, to comply with limits established by ENRE 99/97 and IEEE 519/1992. The other case deals with a 2.5 MW electric arc furnace fed from the public MV network. The carried out measurements harmonics, voltage and current unbalances, active and reactive power, power factor and flicker determined that the high flicker level was the most critical disturbance. In addition, the compensation factors required to comply with reference levels and also to determine the dimension of the suitable static compensator were calculated