Getting outdoor panel branch wiring inside

[Coppersmith]

I am rewiring a house that has a NEMA 3R outside panel. The existing installation has a riser out of the hub on the top of the panel that extends 22". All of the NM cables go through the riser, into the eave, and then distribute through the attic. There is a 6" wide U-shaped sheet metal chase over top of the cables and the riser that is fastened to the wall. The chase extends into the eave and down to 3" above the panel.

I plan on redoing this in the same manner except I'm going to fan out the NM cables and fasten them prior to going into the eaves, and replace the chase with one that is panel width.

This seems to be compliant with (2011) 312.5 exception however I'm concerned whether the inside of the chase and inside of the riser would be considered dry locations (required for the NM).

also, just for curiosity,

312.5 exc (b) makes reference to a structural ceiling I'm not allowed to penetrate directly with the riser. Is the plastic or metal vents covering the eave considered a structural ceiling?

 

[GoldDigger]

...
...

312.5 exc (b) makes reference to a structural ceiling I'm not allowed to penetrate directly with the riser. Is the plastic or metal vents covering the eave considered a structural ceiling?

IMO, no. The roof sheathing and membrane is a structural component (but a roof, not a ceiling), supporting the weight of roofing and persons walking on the roof.
The sheathing, vented or not, on the bottom side of the rafter tails is not structural in any way.

 

[Coppersmith]

Anybody else want to comment on whether what I propose to do is code compliant. I'm really not sure. I'd like to ask an inspector, but they are all busy assessing hurricane damage.

 

[jumper]

You riser and if I understand your chase layout are both technically wet locations. Pretty minor IMO.

300.9 Raceways in Wet Locations Above grade. Where
raceways are installed in wet locations above grade, the interior
of these raceways shall be considered to be a wet location.
Insulated conductors and cables installed in raceways in wet
locations above grade shall comply with 310.10(C).

 

[Coppersmith]

You riser and if I understand your chase layout are both technically wet locations. Pretty minor IMO.

300.9 Raceways in Wet Locations Above grade. Where
raceways are installed in wet locations above grade, the interior
of these raceways shall be considered to be a wet location.
Insulated conductors and cables installed in raceways in wet
locations above grade shall comply with 310.10(C).

Location, wet - ... and in unprotected locations exposed to weather.

Location, damp - Locations protected from weather and not subject to saturation...

The chase, riser and panel are under an eave. But they are several feet below it. Is that a wet or damp location?

Even if under the eave is a wet location, the outside of the chase will get wet just like the outside of the building will get wet. The inside of the building is dry. Seems to me the inside of the chase is dry as well. The chase will butt up against the eave venting so no water is going to get in the top.

Location, dry - ... a location classified as dry may be temporarily subject to dampness or wetness, ...

Based on the above definitions, I think the inside of the chase and the riser under it is a dry location. Where am I thinking wrong here?

 

[jumper]

Under an eave, which is 2 or 3 ft wide usually, is pretty exposed IMO, and is a wet location. Up to your AHJ to call it at best a damp one.

300.9 Raceways in Wet Locations Above grade. Where
raceways are installed in wet locations above grade, the interior
of these raceways shall be considered to be a wet location.
Insulated conductors and cables installed in raceways in wet
locations above grade shall comply with 310.10(C).

 

[JFletcher]

Would it be possible w/o affecting working space to frame out or reframe the existing wall a bit so that that cables would then be in a dry location?

 

[Coppersmith]

Would it be possible w/o affecting working space to frame out or reframe the existing wall a bit so that that cables would then be in a dry location?

I thought about that. I could run pressure-treated 2x4 on either side of the panel up to the eave and screw a metal cover over it, but that's about the same as the u-shaped metal pan that I already proposed using. I think either way would make the interior of that space a dry location. (Maybe not the top of the panel, but several inches above it, and definitely from the top of the riser to the eave.)

How are the branch circuits normally brought into these exterior panels? I really can't come through the wall from the inside. The stove and cabinets are opposite the panel. I can go inside the block from right below the lintel, but that seems hard.

 

[JFletcher]

I thought about that. I could run pressure-treated 2x4 on either side of the panel up to the eave and screw a metal cover over it, but that's about the same as the u-shaped metal pan that I already proposed using. I think either way would make the interior of that space a dry location. (Maybe not the top of the panel, but several inches above it, and definitely from the top of the riser to the eave.)

How are the branch circuits normally brought into these exterior panels? I really can't come through the wall from the inside. The stove and cabinets are opposite the panel. I can go inside the block from right below the lintel, but that seems hard.

I always come in thru the bottom if I can; coming in from the back or top tends to lead to corrosion issues. ofc I'd rather put the panel inside if possible, and I think most electricians here have done the same for ages. Exterior panels are extremely rare in this area, to the point that I once thought it was against code to locate them outdoors.

 

[ptonsparky]

Use UF cable.
Use EMT and THWN to gutter or jboxes in attic.

 

[Coppersmith]

Use UF cable.

NM is already run. I wouldn't want to wire all home runs in entire house in UF nor have to change from NM to UF near panel.

Use EMT and THWN to gutter or jboxes in attic.

A lot more work than I think is necessary. Also I would have to upsize all conductors or derate the branch circuits unless I ran a whole lot of individual conduits down to panel.

Lots of house around here have outside panels. They are always wired with NM. Most times the NM comes through the back of the panel. I also see lots of these with a riser and all cables stuffed in there. Not sure of the legality in current code cycle as I have discussed above. 60% fill would apply. Second riser probably needed. This is an existing panel. I can't move it. I can't wire through the back unless I run all the cable inside the block wall core due to kitchen on opposite side of wall.

 

[growler]

Under an eave, which is 2 or 3 ft wide usually, is pretty exposed IMO, and is a wet location. Up to your AHJ to call it at best a damp one.

300.9 Raceways in Wet Locations Above grade. Where
raceways are installed in wet locations above grade, the interior
of these raceways shall be considered to be a wet location.
Insulated conductors and cables installed in raceways in wet
locations above grade shall comply with 310.10(C).

I have read this several times to try and get an idea of where the Coppersmith is comming from and I finally see his point.

A raceway ran on the outside of a building would be a wet location. But if you put that raceway inside a chase that is dry then it shouldn't be a wet location any longer. I'm not sure the metal cover that he is going to use would be acceptable to AHJ ( probably worth a try) but I'm thinking that it would be possible to build some sort of chase that would be a dry location.

I would do allmost anything to keep from splicing those cables in the attic unless they are real easy to get to and most of the time they are not.

If I had to get a carpenter to build something that looks nice then so be it. A chase we would have.

 

[oscarcolumbo]

I thought about that. I could run pressure-treated 2x4 on either side of the panel up to the eave and screw a metal cover over it, but that's about the same as the u-shaped metal pan that I already proposed using. I think either way would make the interior of that space a dry location. (Maybe not the top of the panel, but several inches above it, and definitely from the top of the riser to the eave.)

How are the branch circuits normally brought into these exterior panels? I really can't come through the wall from the inside. The stove and cabinets are opposite the panel. I can go inside the block from right below the lintel, but that seems hard.

I've asked myself that question for a long time. I've wired houses and then bought the branch circuits in the wall into the back of the panel, but that's a new install. An existing install is different. I've thought about framing the chase with 2x4's and covering it with plywood then putting that tyvek paper that's used before stucco. And then someone could stucco over it. The tyvek makes it water proof.


Sent from my iPhone using Tapatalk

 

[Coppersmith]

Update:

So I was finally able to talk to an electrical inspector and got very bad news. Spoke to a second one, got same story.

Bringing all the cables through "stove pipe" riser sleeves on top of panel (the pipe is not continuous to inside) is OK as long as max fill is 60% and pipe is at least 18" long. Cables emerge from pipe and have to be fastened within 12".

However, according to them there is no way to make the location above the outdoor panel dry, therefore NM cannot be used. I have to replace every home run with UF until I get inside, then I can continue to first box or set a box closer and change to NM. I politely argued a bit since I think this is BS.

* Chase made from metal pan placed over the cables from eave to just above panel - No.
* Chase made from pressure treated 2x4 with metal or PT plywood cover? - No unless stuccoed over making it inaccessible.
* Even if sealed with caulking? - No.

The definition of "Location: dry" says "a location classified as dry may be temporarily subject to dampness or wetness," which I think fits the above methods perfectly. The NM cables are not going to get wet inside the chase unless a hurricane blows rain sideways into the gap between the panel and the bottom of the chase (about three inches). Then they might get temporarily damp or wet. This is no different than running NM in a crawl space open to weather which is common here.

I went ahead and changed all the cables to UF at significant expense because I need to get this job done, but I would like to continue to pursue this. Who is right here? If it's me, I'd like suggestions for how to get an official ruling on this situation.

---------------------------------------

I asked about other methods of cable entry:

* Bringing all the cables through the block wall into one big KO in back of panel - Not allowed, they need to be individually fastened at panel.

* Bringing all the cables fished down the block core then into one big KO in back of panel - Not allowed, they need to be individually fastened at panel. Even though they are fished? Not allowed.

* Bringing all the cables through the block wall from a big j-box into one big KO in back of panel - allowed. Unfortunately the kitchen is opposite the panel so I can't use this method on this job.

Inspectors suggested method - knock out an entire 1/2 block behind the panel (but not one that is filled with concrete) and make a series of individual KO's with connectors for cables. He said they are listed as follows:
1/2" connector - max two cables.
3/4" connector - max three cables.
1" connector - max four cables.
1.25" connector - max five cables.

I've never seen this done but he claims that how to do it.

 

[Ragin Cajun]

Just got a project where the existing house panel is on exterior wall.@#$%^&*. Not one circuit is labeled, either. The owner said he would label them.

New owner is extending house on same side as panel which will be removed. All the branch circuits need to be pulled from the panel mostly to in the existing crawl space. Plan on running them to a large J box. The new panel will be in the middle of the new addition so we have to extend every circuit into the new crawl space and up into the new panel. That's going to be a real cluster.
Any suggestions how to splice the old to new in the J box? Wire nuts in this application are distasteful. Terminal blocks? Or what?

We have to keep the old panel hot until the addition is hot. The existing panel is fed underground so we will have to install a temporary service to it. Going to be "fun"!

RC

 

[Smart $]

... got very bad news. ...

I've followed this thread but haven't contributed because I suspected the inspectors would reject all NM methods.

Given they suggested a couple methods, I have a question. Does the damp/wet prohibition of NM extend to the jacket-stripped conductors inside the exterior located panel?

 

[Coppersmith]

Does the damp/wet prohibition of NM extend to the jacket-stripped conductors inside the exterior located panel?

It's a NEMA 3R panel so I would think the interior would be considered a dry location.

 

[Smart $]

It's a NEMA 3R panel so I would think the interior would be considered a dry location.

Yet the inside of weathertight raceway methods is to be considered damp or wet where installed in such locations. Why would the inside of a weather resistant exterior panel be any different? :huh:

 

[packersparky]

Yet the inside of weathertight raceway methods is to be considered damp or wet where installed in such locations. Why would the inside of a weather resistant exterior panel be any different? :huh:

Because the code book says so.

 

[Coppersmith]

Plan on running them to a large J box. Any suggestions how to splice the old to new in the J box? Wire nuts in this application are distasteful. Terminal blocks? Or what?

I've done several like this and always used wirenuts without incident. Just make sure you get a big enough box. All those wires take up a lot of space.