Re: Network Cable Interference
If the 18 AWG you speak of has a class 1 power supply then by code you cannot run CAT 5 or 6 cable in the same conduit. Class 2 or 3 OK.
In any event it is not wise to run Cat 5 0r 6 closely grouped with any conductors (like conduit) including Cat 5 or 6. For best performance they sould be seperated.