The damage rate (electrical resistivity increase per fluence unit δρ/δΦ) has been measured in cubic tantalum carbides TaC0.99and TaC0.80, during irradiation at 21 K by electrons of energiesEranging from 0.4 to 2.7 MeV. Both experimental δρ/δΦ versusEcurves clearly display two thresholds atE< 0.35 MeV andE< 1.5 MeV. Comparison with theoretical displacement cross-sections calculated for TaC allowed us to attribute unambiguously the first threshold to carbon displacements and the second one to tantalum. Surprisingly, in the largely substoichiometric TaC0.80sample, irradiation still creates carbon Frenkel pair type defects. Taking into account the real irradiation conditions, the deduced parameters areTCd= 28 ± 6eV andTdTa= 42 ± 2eV for the threshold displacement energies in TaC0.99(resp. 28 ± 6 and 32 ± 2eV in TaC0.80), and ρCF= 26 ± 5 μΩ-cm/at.%. for the specific mean resistivity of carbon Frenkel pair in TaC0·99.