Cold air return wiring restrictions

[Stevenfyeager]

Does NEC prohibit any device, outlet box, switch box, light box in a cold air return cavity in a house ?? Also does it restrict nm cable ? Wires parallel or pendicular make a difference? Thank you.

 

[gadfly56]

Does NEC prohibit any device, outlet box, switch box, light box in a cold air return cavity in a house ?? Also does it restrict nm cable ? Wires parallel or pendicular make a difference? Thank you.

It's a plenum space, so the rules for such spaces apply.

 

[Andy Delle]

Does NEC prohibit any device, outlet box, switch box, light box in a cold air return cavity in a house ?? Also does it restrict nm cable ? Wires parallel or pendicular make a difference? Thank you.

Well in commercial I do believe this would invoke a plenum situation.

But in my house for example built in 1990 the upstairs furnace has a wood stud / drywall cavity next to a closet down from the attic for the return air. They install the return air filter on the second floor for easy servicing. And there is Romex and boxes penetrating that cavity.

So it is done. Perhaps it is or was at one time legal in residential?

 

[augie47]

FYI: 300.22 is your Code reference