Briefly, Article 800.52 (A)(2) of the 2002 NEC code states “Communications wires and cables shall be separated at least 50 mm (2″) from conductors of any electric light, power, Class 1, non-power limited fire alarm, or medium power network-powered broadband communications circuits.” There are two exceptions 1) the use of specially designed and rated raceway having separate channels where “all the communications circuits are encased…” and 2) where the cables are “separated by a continuous and firmly fixed nonconductor, such as porcelain tubes or flexible tubing, in addition to the insulation on the wire.” In addition to the NEC code, your installation may be subject to state, county and local codes and ordinance.