  In the context of $SU(2)_L\times U(1)$ dimension six operators we study the
potential of the LHeC to provide information on top quark effective
interactions. We focus on single antitop production and how it is affected not
only by the effective $tbW$ coupling but also by four-fermion operators.
Compared to the LHC, the LHeC provides a cleaner environment to make a precise
measurement of the top quark production cross section. Therefore, this machine
would give a much better assesment of $V_{tb}$ in the context of the SM or
$V_L$ in the context of higher dimension operators. The LHeC could also give a
slightly better measurement for $V_R$. For $g_R$ the HL-LHC precise
measurements of $F_L$ and $F_R$ (the $W$-boson helicity decay ratios of top)
would yield better constraints than those obtained by the LHeC. Lepton-quark
contact interactions would also be significantly better probed by the LHeC,
since the only way of measuring them at the LHC would be through leptonic top
decay which is hardly sensitive to these interactions.
