No subject

low-voltage wiring such as CAT5.  Therefore, it's not even considered
electrical wiring in the elctrical inspection.  As far as the electrical
inspector is concerned, it's as irrelevant as a water pipe.[1]

It's possible that local jurisdictions have additional rules governing
low-voltage wiring, but unlikely.  Most just follow the NEC.

Now, it is of course necessary that any modifications you make not
interfere with wiring, structural integrity, etc.  (The low-voltage wiring
must be totally separate from the electrical wiring.)  And you should
follow guidelines such as box height, and of course follow fire safety
guidelines.  (The main fire safety guideline is to use "plenum" rated
cable if you run it through air ducts or plenums.  Don't use the cheaper
PVC, since it will release deadly chlorine gas if burned in a fire.)

Hope this helps,

Jeremy

[1] Well, electrical inspectors do care about metal water pipes if they're
part of the house's grounding system.  But this isn't used in new homes.