Running Wires in Conduit inside a wall

Andi.M

Here is the situation.

I am in the middle of remodeling a bathroom on the upper floor of a split-foyer. It is right above the unfinished laundry, where the electric box is situated (the lower level is the basement and above the first floor is an unfinished attic). I have taken everything off down to the framing. In the corner of the bathroom there is a roughly 3x4 enclosed passageway that runs straight from the laundry to the attic. In it, the builders ran the main A/C air duct to upper floor, as well as the flue from the Gas Water heater and Furnace.


I had this idea about running 2 conduits from Basement to attic to “future-proof” the place and get ready for future remodel ideas! Conceptually, I would use one to fish electric wires (I was thinking of the usual 14/2 NM-B and 12-2 Romex NM/B which have been ran elsewhere) and the other to run low-voltage wires (RG-6 and Cat 5e. perhaps speaker wire). The purpose of the conduits would have been to simply have a path (it will be about a 9 foot run) between the attic and the basement) to simplify future wiring.


As I look into this, there seems to be more to it than the electrician at the local home improvement store conveyed. I am hoping readers here have better ideas:
1.

What other approach would you use (if not what I trying to do) to accomplish the same purpose? (the rest of the house if finished and I won't get the same straight shot to laundry on any future project)



2. If going the conduit route, I was recommended to use 2 x 1inch PVC 10 foot conduits.
a. Would that be OK for low-voltage wires;
b. I have come across things like fill % (seems to be 40% for 1” pvc pipe) for NM wire in conduit. Apparently, there is danger of overheating. But this would barely give me 2 runs and defeat the purpose of what I had in mind! Ideas?
c. If I run a conduit, what could I do at the two ends for:
i. Fire protection;
ii. Prevent Insects from crawling it;
iii. Preventing heat loss from basement to attic
Thank you

rjniles

As cheap as PVC is, run 10 pieces of 3/4". Seal the ends with duct seal.

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Location:
Coastal South Carolina

k_buz

The exhaust for the water heater is running inside a wall?

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buddy builder

i do this "for future use" conduit all the time. i would use at least inch and a half conduit. it's ok to be too large. a letdown to have thought of this beforehand but not sized large enough. you may want to run something besides electrical lines in them later. when i install a breaker panel i usually stub a one inch conduit up into the attic high enough to gather attention for future use. when i build a house, as the contractor i will even put three inch pvc under the drive at each end. then put two inch under the walks. i put unglued caps on the ends above ground and glue the caps when underground.

buddy builder

good question kbuz. if the chase wall is open on top and bottom is it considered a wall?

Andi.M

Yes, in this enclosed 3x4 shoot that goes from Basement to Attic. It is enclosed by 2x4s all around. On the top (to attic) and bottom (basement) there is a metal sheet that encloses the area. The AC duct goes to attic and then feeds down to some rooms upstairs. The water heater exhaust (warm to touch) goes straight out the roof.

Thanks

Andi.M

That's great!

If I run 1.5" PVC straight from basement to Attic, would I be able to fish standard NM wire through it? Any limits in terms of the number of wires?

How would I seal the top / bottom of the conduit (the remaining space), but still be open to easily reopen to fish additional wires? I am concerned about leaving an open path for bugs / air flow / fire between basement / attic.

Thank you

Jim Port

If the chase already exists it is easy to drop a weighted string down into the basement and pull cables into the attic.

I would stuff the top and bottom to stop air movement and to limit the chimney effect in the event of a fire.

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Answers based on the National Electrical Code. Local amendments may apply. Check with your local building officials.

Andi.M

Thank you. Is this in lieu of running a conduit for electrical?

Just make a hole in the metal sheeting on the top (Attic) and bottom (Laundry) of the chase everytime a new wire is needed, run the wire, and then seal around the hole with fireretaring caulk?

For low-voltage wires, would you use a similar approach or use a conduit?