The van Allen radiation belts are regions in the terrestrial space environment that present energetic ions and electrons trapped by the geomagnetic field.The increase of fluxes for these energetic particles during geomagnetic storms has a major interest for Space Weather, mainly due to the impact on satellites and human activities in space. A detailed knowledge of the extreme fluxes reached for different electron energies as well as the frequencies of occurrence is essential for the specific design of satellites and for the development of satellite technologies.The main purpose of the present work is to study the extreme electron fluxes in the terrestrial radiation belts, for an energy range between 0.249 MeV and 0.802 MeV at 660 km of altitude above the Earth surface, using measurements made by the detector ICARE-NG/Carmen-1 on board the polar Argentinean satellite SAC-D.A statistical analysis based on the extreme value theory was implemented for the daily average electron flux in the outer radiation belt and in the South Atlantic Magnetic Anomaly (SAMA).We found that the cumulative distribution function of the daily averaged electron flux is likely to have a finite upper limit in the core of the outer radiation belt (4.0<L<4.5) and for electron energies between E>0.270 MeV and E>0.413 MeV. The extreme electron flux value expected in 1, 10, 50 and 100 years were computed at L=4.5, showing a general decreasing trend with increasing energy. Although the results in the SAMA suggest that the cumulative distribution function of the electron flux is likely to not have a finite upper limit, this result is not statistically significant.The results presented in this work are important for the satellite engineers to improve devices and materials for the development of future satellites. Also, the likely magnitude of an extreme event in the outer radiation belt is of interest to the satellite insurers to help them evaluate potential disaster scenarios.