Can I use NM cable NEC 300.22 ?

[stevenj]

NEC 300.22 Wiring Question.
NEC 300.22 C execption ( wiring though ) Can NM cable be used for wire though?

HVAC supply air duct, quite large 11x 21 in dropped ceiling hallway. Could I use NM Cable for the runs that go above and alongside the supply duct? The NM would be fastened in the standard way to the joists. The joists are above the duct, and standard 2x4 inside walls.

300.22 states wiring installed in duct or plenums, anyplace where it says around the duct. I notice 300.22 states chamber. Does this count as a chamber ? I have 6-8 inches on either side of the duct and 2x8 joists above or am I reading this wrong.

I’m take It I only can use MC IMC MI, EMT,etc. and not NM cable at all.



Also The supply duct sets on 2x4 ‘s over a hall ceiling that will be rocked. I need to put fixtures on these 2x4’s i.e., 1.5 boxes would NM ok, as this would be below the supply air duct on the 2x4 with a steel box.

So My general question is can NM be used all.

 

[Jim W in Tampa]

your not very clear in question. Are you asking to run inside the duct or just on outside near it ? Is area your in plenum rated ?

 

[stevenj]

your not very clear in question. Are you asking to run inside the duct or just on outside near it ? Is area your in plenum rated ?

Im just asking to run the conductors outside near the duct. the space in not plenum rated.

 

[ActionDave]

Is this a non-dwelling unit?
When you say drop ceiling do you mean suspened ceiling?

 

[stevenj]

Is this a non-dwelling unit?
When you say drop ceiling do you mean suspened ceiling?

this is a dwelling unit ( home ) the hvac guys just lowered the hallway ceiling to fit the large duct. that all .

 

[dcspector]

Steve I think you answered your own question in your OP....300.22(C) Exception if I understood your application completly.

 

[infinity]

Since the air will only be moving inside of the ducts your installation does not fall under 300.22(C). Since this is a dwelling the NM is permitted above the hung ceiling. You're good to go.

 

[stevenj]

Steve I think you answered your own question in your OP....300.22(C) Exception if I understood your application completly.

I think your right . re-read the 300.22 again.

 

[stevenj]

Since the air will only be moving inside of the ducts your installation does not fall under 300.22(C). Since this is a dwelling the NM is permitted above the hung ceiling. You're good to go.

Than you for the clarification on this . I was not sure if 300.22 or exception (c) applied to a dwelling.

thanks .