HVAC open (not in conduit) control cabling

[Chan711]

Is it legal to fasten 24v HVAC DDC cabling directly to the air supply duct work(on the outside of duct) it controls? If you have a network of DDC system controllers comprised of several VAV devices along a section of supply duct work, is it permissible to attach the cabling (24Vac) to the duct work with approved cable supports?

 

[Dennis Alwon]

I don't see why not unless their is an HVAC issue. I have attached discos to furnaces,,,,,,,,

 

[Gregg Harris]

Is it legal to fasten 24v HVAC DDC cabling directly to the air supply duct work(on the outside of duct) it controls? If you have a network of DDC system controllers comprised of several VAV devices along a section of supply duct work, is it permissible to attach the cabling (24Vac) to the duct work with approved cable supports?

Not an issue,it is done all of the time.

 

[jcassity]

Ive seen it done a lot, then i see the lawn mowers and weed wackers cutting it.

I dont "permit" it on my projects, and i pay to have it done how i permit which is "in emt within the inside of the faclity" and "in carflex or liquid tight" upon
exiting the building and up the the packaged unit.

we added lead lag controllers to this facilities exsting units and the old install had the control wires zip tied to the hvac power run in liquid tight.
that showed much evidence of wear and tear....
we added a N3R box and liquid tight up to the unit and that houses our control wires.

 

[cadpoint]

2", Most install Codes apply that each service should be seperated at least that amount from another service.

If a circuit as decribed, to a piece of equipment, sure why not... A trunk of wires needs to be independantly supported.