Tito, please. People spend a lot of time and money to understand what I'm telling you. You can't just read the book and take it at face value.
Reread 800.133(A)(2) with particular attention to Exception #1. You need to understand that
conductors are the individual current carrying cunductors such as THHN within a raceway, conduit or cable, NOT the cable itself. So, per 800.133(A)you cannot run LV communications cables in the same raceway or conduit (or enclosure) that also contains Class 1 or power conductors unless there is a suitable barrier to separate the line voltage from the low voltage.
Now, Exception #1 allows an exception and that is if the Class 1 or power conductors are within a listed cable assembly such as MC, AC, Romex, etc. no separation needs to be maintained. Alternatively, the communications cables could be enclosed in a raceway.
In Article 800 page 70-669 a communications circuit is defined as:
"The circuit that extends voice, audio, video, DATA, interactive services, telegraph (except radio), from the communications utility to the customer's communications equipment up to and including terminal equipment such as telephone, fax machine, or answering machine."
Here you need to know that it has been interpreted that the operative phrase is
from the communications utility to the customer's communications equipment meaning that a communications circuit orginates outside the premises from a utility or common carrier. Thus only certain data circuits such as T1 etc. would fall into that category. Since ethernet and even voice or digital circuits out of a PBX or system do not originate outside the premises it was determined that they are not communications circuits per the NEC. Like I said, I don't agree and I believe that the NEC needs an updating in areas of technology.
-Hal
