Running High Voltage and Low Voltage Wiring

ETC’s preference is to keep data and power in separate conduits/trays because signal interference can occur when low voltage control wiring is run with branch power wiring. This is not always the case, but this is very likely. Use of Class 1 wiring methods will not protect against signal interference.

With that being said the NEC allows circuits that are Class 2 to be run with circuits that are Class 1, provided Class 1 wiring methods are used throughout the entire run (not just in the location where both wires are ran together). What this means is both the low voltage and branch power wiring must be rated higher than the largest potential within the conduit/tray. This can be a point of contention for some AHJ's. One AHJ will look at the insulation on the wire as being a sufficient enough barrier between the low voltage and branch power wiring. While another AHJ will require the low control wiring to be run in a separate conduit/tray from the branch power wiring. Be sure to consult with the local AHJ before designing your systems.

All ETC equipment that uses both power and control wiring is designed to aid this separation and their installation manuals discuss both the fact that they should not be run together as well as how to feed them in separately.

For example:

• Echo Room Controllers and Foundry Mini panels have high-voltage headers and conduit knockouts on the left side of the panel and low-voltage headers and conduit knockouts on the right side of the panel.
• DRd and Sensor Rack Enclosures offer multiple conduit access points, with their respective manuals pointing out which ones are available for high-voltage or low-voltage.