Is carbon tetrachloride an electrolyte?
No, $\ce{CCl4}$ is not an electrolye.  An electrolye is a material that causes ions (charged entities) to form in the solvent.  Carbon tetrachloride neither dissociates into ions nor induces ion formation in the solvent.

The reason is that the $\ce{C-Cl}$ bond is rather strong and won't break under
normal solution conditions.  Nor does the molecule have any net dipole moment.