Suggestions For Running Conduit Through Exterior Wall

[fromlalaland]

Hi, I am installing a patio heater, it's a dual element 6000watt. I will be wiring each element independently so I will be installing it on 2 x 20amp circuits. However, I want the ability to add more heaters down the road, so I opted against running romex and using conduit instead.

My plan is to use 1in PVC conduit, I will be coming from a crawl space that we drilled into the sill plate to get to and then a friend helped take off the siding and open up the exterior wall so we can run conduit up the wall (was required regardless because of fire block in the way). I am able to get a 90 into the wall from the crawl space, then go straight up the wall with the 1in conduit, however I am debating how to terminate the end at the top of the wall where the heater(s) will connect.

A 1in 90 elbow wont have enough room to do its sweep. Since it's inside the wall, a LB wont help. I had thought perhaps I could put a box inside the wall so that the conduit just has to come into the bottom side of the box, but then I would need a way to make it water tight and then transition to the outside of hte wall where i will need to run conduit against the shingles to the heaters.

Also, I want to make sure I understand the NEC code correctly, since the maximum size of any individual circuit is 20amps, i can run 1 single 12awg equipment ground? I was going to run wire for 3 heaters: 2 wires per element, 2 elements per heater times 3 heaters would be 12 x 12awg stranded THHN + 1 x 12awg stranded EGC? The code says 12awg is needed for maximum circuit size of 20amp and if they are all in the same conduit, I can use just 1?

Perhaps I am overthinking this and should just run 6 x 12/2 romex instead? It would be a lot easier for sure. I liked the idea of the conduit incase some future use comes up and I could pull more wires.

Thanks

 

[AntonLargiader]

I installed a similar system (three single-element heaters at this point). If you want to expand it in the future, consider installing a small outdoor subpanel closer to the heaters, rather than pulling all of those circuits individually. Obviously this will depend a lot on your actual layout; maybe a panel would be an eyesore no matter where you put it. But if it is workable, if will give you future flexibility. Maybe you will want to install things other than heaters out there, like a powered awning, lights, etc. that may want something other than 12/2.

 

[mike93lx]

Romex is not allowed outdoors, regardless of conduit, so if the wire will be outside the wall, it's conduit and thwn or you could use uf-b if it is protected from damage

 

[billconner]

Conduit or Romex in the wall, there is still the transition problem. I think a recessed box and then a NEMA R3 surface box over it?

No way to accept I" conduit surface mounted on exterior? Seems ever so much simpler. Appreciate your concern for appearance.

The Romex in the wall and into back of one or more surface mounted NEMA R3 boxes is also pragmatic.

 

[ycgoat]

If the problem is the radius of the bend of the conduit, you can notch the wall where it enters the wall cavity and fill it in after the the conduit is installed. For future expansion outside you will need a Jbox somewhere, such as;
Outside, in the crawl space, or in the wall. For in the wall you could cut and patch the wall Everytime you install a conduit or put in an access panel

 

[fromlalaland]

I installed a similar system (three single-element heaters at this point). If you want to expand it in the future, consider installing a small outdoor subpanel closer to the heaters, rather than pulling all of those circuits individually. Obviously this will depend a lot on your actual layout; maybe a panel would be an eyesore no matter where you put it. But if it is workable, if will give you future flexibility. Maybe you will want to install things other than heaters out there, like a powered awning, lights, etc. that may want something other than 12/2.

You actually arent far off my current plan. There is a sub panel currently about 15ft from where I am installing the heaters. That is where I plan to run the conduit to. However, the sub panel is only fed by 6awg, so my plan was to either A) upgrade the service to the sub panel to be able to support 2-3 heaters (100-150amps) or more likely just run a new sub panel right next to it just for the heaters. Perhaps a 100amp sub panel, I could run 1 heater off the existing sub panel and then 2 heaters + other stuff off the new sub panel.

A powered awning and lighting are definitely on my mind, that is why I was wanted to run the 1in conduit so I could run 3 heaters + have room to run new conductors if needed. However I wont have a lot of room left, I could possibly try to fit 1 1/4 or 1 1/2.

Romex is not allowed outdoors, regardless of conduit, so if the wire will be outside the wall, it's conduit and thwn or you could use uf-b if it is protected from damage

Good point, funny thing is, electrician friend said run 2 romex and be done with it. Perhaps he meant to put a j-box IN the wall and then the romex never goes outside? is a j-box in the wall with exterior access considered outdoors? Could the romex not be brought into the exterior mounted NEMA R3 box and then transitioned to THHN to the heaters as billconner suggests below?

Conduit or Romex in the wall, there is still the transition problem. I think a recessed box and then a NEMA R3 surface box over it?

No way to accept I" conduit surface mounted on exterior? Seems ever so much simpler. Appreciate your concern for appearance.

The Romex in the wall and into back of one or more surface mounted NEMA R3 boxes is also pragmatic.

Well a recessed box with a NEMA R3 surface box over it is a great idea, I actually was thinking of this but couldnt come up with a way to do it and have it be water proof. What kind of recessed box would I use? How would I attach the NEMA R3 surface box to it? This would make using conduit much easier as I dont need a 90 at the top of the wall (it's a 2x4 framed wall I forgot to mention). Is there a NEMA box that is like an extension box that can mount and seal to an existing box? I would need access to the box in the wall if this was to work, otherwise I wouldnt be able to run more wires.

Romex in the wall into the back of a surface mounted NEMA R3 box what I had in mind, I am not sure if its allowed (See comment above) but it would be a very pragmatic approach as you say. This limits future changes, although I could run perhaps 8 x 12-2 and have at least a couple extra lines if needed.

I dont want to have to cut open the side of my house again, that was one of the main reasons for the conduit. I am not sure running the conduit outside of the house makes it much easier though. I would still need to transition from coming out of the sill plate (at an angle) and then get an LB on it. I guess I could heat the PVC and make a custom elbow though. This is probably my fall back plan.

If the problem is the radius of the bend of the conduit, you can notch the wall where it enters the wall cavity and fill it in after the the conduit is installed. For future expansion outside you will need a Jbox somewhere, such as;
Outside, in the crawl space, or in the wall. For in the wall you could cut and patch the wall Everytime you install a conduit or put in an access panel

The problem is it's a 2x4 framed wall, so I only have 3.5inches of space to work with between the sheetrock and the sheathing. We notched the sill plate to get the eblow into the wall but I dont think that can help at hte top unless I nothced the sheetrock inside the house (which I would rather not do!)

My hope was to get a NEMA enclosure at the top of the wall, exterior mounted with the conduit going into the back, but that is only possible if i can figure out how to get the elbow into it (or a box on top of a box as mentioned.


Thanks everyone.

 

[Jim greengo]

Pictures?

 

[fromlalaland]

Pictures?

I forgot to take a better picture of where we came through the sill plate before we sealed it up with plastic:




The junction box was going to go at the top of the cut and the heater where my friends hand is.

 

[kinglew]

Conduit or Romex in the wall, there is still the transition problem. I think a recessed box and then a NEMA R3 surface box over it?

No way to accept I" conduit surface mounted on exterior? Seems ever so much simpler. Appreciate your concern for appearance.

The Romex in the wall and into back of one or more surface mounted NEMA R3 boxes is also pragmatic.

Why can't you run on the top of siding ?

 

[fromlalaland]

Why can't you run on the top of siding ?

I could but my friend talked me into hiding in the wall.

He was like, i already pulled off the siding and cut a hole to get into the crawl space, might as well just open the rest of the wall up and make it look nice and hide the wire.

 

[billconner]

For a recessed box in wall and NEMA R3 on surface, just cut hole in back of surface box to match recessed. I'd put it flashing at top of surface box if eave doesn't protect it.

I believe a recessed box in exterior wall opening to exterior OR a surface box on exterior sheathing can be fed with Romex all inside the wall. Many porch lights, receptacles, flood lights, etc done this way. Yes, run some extras. (But I instinctively like the conduit.)