This paper concerns a time-independent thermoelectric model with two different boundary conditions. The model is a nonlinear coupled system of the Maxwell equations and an elliptic equation. By analysing carefully the nonlinear structure of the equations, and with the help of the De Giorgi-Nash estimate for elliptic equations, we obtain weak solutions in Lipschitz domains for general boundary data. Using Campanato's method, we obtain regularity results for the weak solutions.