I would seriously question the overall competence of any electrician who ran any low voltage cable in direct contact with AC power cables. This practice is not permitted by the electrical code. An electrician who does not respect that code requirement might be cutting corners with the code in other areas, too.

While the level of knowledge among electricians regarding network wiring is gradually increasing, the conventional wisdom for anyone who wants network wiring installed professionally is to hire a contractor that specializes in low voltage wiring.