Does the NEC

Low voltage (12-24v.) is an ambiguous term when applying the NEC. Circuits that you may be referring to are either Class 1, Class 2, Class 3, or Motor Control circuits. Class 2 circuits must be supplied by a power supply labeled Class 2 that is generally limited to 100 Volt-Amperes and 30 volts maximum (see Table 11A and 11B in Chapter 9 of the NEC). These circuits cannot be run in the same raceway as power circuits or Class 1 circuits. They can be run into a box or cabinet with power when supplying common equipment if .25 inches of separation is maintained and can be run in gutters and boxes with power if properly installed with separation barriers. Section 725.55 delineates more rules.

Just as I've found in alt.building.construction, there are a lot of great people participating here with little or no conflict. To each of you who offer your expertise (and time) so freely, I salute you!