Looking for a Special PVC Junction Box...

[larry4406]

Not sure if such a beast exists, but figured the collective wisdom here would know.

Running power to a detached barn (90A MHF, separate neutral and ground, blah blah) from my house.

I want to run the SER down (the wall cavity) of the exterior 2x6 wall of my insulated attached garage, into the top of a junction box (which is inside the wall cavity) which is then extra deep with a nailing fin (for siding/flashing) then drop down to the ground while exterior to the siding. The junction box would allow me to connect the SER to the MHF. It would have a removable cover with a gasket.

See crude sketch. I'm thinking 12x12 (wxh) x 8-12" deep? Does such a beast exist with the nailing fin?

Zero access to the back of the junction box (finished bathroom) unless I relocate the junction box to the other side of a deck which increases the cable runs by 60'+. No access to the interior so could not put an LB as the cover would be non-accessible.

I would be removing vinyl siding, cutting the Dow foam insulation under the siding (1987 construction...), installing the junction box, feeding from the attic above, reinstallation , etc. All from the exterior.

Only other option I see is to use the 12x12x6 surface mount junction box and run exposed conduit from the soffit down to the junction box (at grade) which then transitions to the MHF. This will look amature and poor in my opinion but maybe only reasonable path forward.

Thoughts?

 

[Marctrees]

Just a comment on the "nailing fin" part.

I have always drilled a few holes through the back.. and attached to structure w sufficient # of appropriate screws, fender washers, and RTV.

Just my idea, those little mounting feet always look too flimsy to me.

Code or not, never had a problem.

So, in your case if you need to partially recess the box, put blocking behind it at appropriate depth, and mount like I do.

Or if you can't do that for some reason, get light gauge AL angle at Hardware store and make fins.. Sheet metal screw from inside of box into the AL.

Marc

 

[Skiff Builder]

Larry,
If you had to ,how about SER in wall, Pvc box surface mount on siding with SER coming through the back of the box, than your MHF conduit out the bottom.
Only thing additional showing on ext house would be the J box- Paint to match siding. Simple hole saw hole easier than recess box?

 

[larry4406]

Larry,
If you had to ,how about SER in wall, Pvc box surface mount on siding with SER coming through the back of the box, than your MHF conduit out the bottom.
Only thing additional showing on ext house would be the J box- Paint to match siding. Simple hole saw hole easier than recess box?

I would like to run conduit in the wall as drawn. Thus no room to turn conduit into the back of the junction box with only a 2x6 wall. This will serve the barn as well as a future generator thus the conduit and two pipe holes drawn.

Keep the thoughts coming.

 

[Skiff Builder]

How about a 1-1/4” conduit with an L. B. Going into the box?
Cut an opening just big enough in the siding to slip it on. Than into back of box, which would still cover hole you made.

Or could you run the MHF all the way up the stud cavity in conduit and transition to SER up above?

 

[RustyJunk]

Search for a non-metallic electric enclosure, I know Hubble makes them in all different sizes, Granger or any good industrial supply will have them.

 

[Dagny]

Gota be a way to do it with no splices.

 

[alfredeneuman]

Gota be a way to do it with no splices.

There are 2 ways.
Either run conduit all of the way and use individual conductors or...
Run conduit wherever it's inside or on the structure and use MHF cable.

 

[larry4406]

How about a 1-1/4” conduit with an L. B. Going into the box?
Cut an opening just big enough in the siding to slip it on. Than into back of box, which would still cover hole you made.

Or could you run the MHF all the way up the stud cavity in conduit and transition to SER up above?

Thought about the LB approach into the back of the junction box but as I said in the first post, the cover on the LB would be towards the wall interior and not accessible. Not sure I could feed the cable thru without the LB's cover removed to make the turn.

 

[larry4406]

Search for a non-metallic electric enclosure, I know Hubble makes them in all different sizes, Granger or any good industrial supply will have them.

I have searched this term but have not found anything with a nailing fin/flange for siding/flashing.

 

[Skiff Builder]

Larry,
How about slipping the lb over the cable outside of the house and than pushing it up and inside the hole onto conduit. Not standard but....
Try it on a mock-up piece of scrap ply.
I just ran my MHF feeder to shop- conduit below ground and above through house to load center. Used numerous 90,s and lb/ll/lr. That cable was slippery. Easy enough to do the 120’ run solo.
Got to get creative sometimes man. Best of luck with the pull!

 

[larry4406]

Larry,
How about slipping the lb over the cable outside of the house and than pushing it up and inside the hole onto conduit. Not standard but....
Try it on a mock-up piece of scrap ply.
I just ran my MHF feeder to shop- conduit below ground and above through house to load center. Used numerous 90,s and lb/ll/lr. That cable was slippery. Easy enough to do the 120’ run solo.
Got to get creative sometimes man. Best of luck with the pull!

Skiff Builder - My thoughts as well for the intial barn feed if such a junction box does not exist. The future generator feed would not benefit from this approach. Maybe this just means a 2nd siding repair when the generator project occurs.

 

[Fasthotrod]

Unfortunately, I know of no such critter that has an integrated mounting flange like that... but here's my idea anyway. Hope it helps.

If you have a 6" wall (5.5" assumed depth) then you might be able to build a standoff panel in the wall and use a box that mounts in from the back of the box screwed to the standoff panel.

So maybe take a 2x4 ripped down to 2.5" deep and nailed to each stud in the wall back by the sheetrock (left and right sides) which provides the mounting tabs in the wall for the standoff panel. Then secure a 1/2" plywood panel to the 2x4's for a standoff panel. This should give you enough space for the conduit to pass into the top of the box, and allow for some insulation behind the box.

Mark the holes for the box:

...then slide the box into the wall and the conduit fitting and secure the box to the plywood. Use a piece of flashing on the sides, bottom, and top of the box. Use silicone to seal the flashing to the box.

Re-install the siding with some j-channel to frame out the box, which should also help with the rain penetration. Silicone/caulk here would likely help, too.

I'd think a box like this one would work for your application...

https://www.grainger.com/product/RITTAL-16-H-x-14-W-x-8-D-Metallic-5AAC1

Mounted something like this? I kept the view open to see it better and didn't draw the flashing, but it and the OSB and j-channel would be all the way around the box:

I assumed a 2x4 ripped to 2.5" deep, then the 1/2" plywood to give the back of the box 2.5" in the wall. Make adjustments as necessary to clear your conduit run and fittings in the wall. I assumed 1/2" OSB for the wall board... so adjust the measurements accordingly if your wall is 5/8" or something else. I assumed a 1" thick siding material, so you'd likely have about 3.5" between the siding and outer usable area of the j-box. (Before the door assembly came into play and blocked your access.)

If you wanted to make the opening completely waterproof, you could box out the area with concrete backer board and coat it with HydroBan or another approved sealant.

I'd run this past your local office to make sure it's to Code... but it's the first thing that came to mind that attempted to match your drawing. Good luck with whatever you decide to do.

Mark

 

[Marctrees]

Fasthotrod - Awesome well presented solution.

A variation of what I mentioned, but beautifully explained.

Dead serious.. I'm not the OP.. but Thank You.

Marc

 

[LifeLongWNYer]

Wow, FastHotRod, nice drawing and good design. It isn't anything that I need, but i appreciate the work that you put into it.

I am getting ready to build, do you do details like that on a contract basis???

To the OP: Go to your electrical parts wholesaler and ask for the counter person who knows the most about "Hoffman boxes." They have thousands of designs, and if THEY don't have what you need, there are several other firms in that business which probably do.



.

 

[larry4406]

FastHotRod - thanks for the detail drawings. I had thought of this as well but was hoping that a flanged box might exist; apparently this is as rare as hen's teeth. If I went down this path I was thinking on using the sticky-flash to seal the enclosure sides to the siding.

LifeLongWNYer - I have been looking at the Hoffman Boxes and am familiar with them.

 

[gungatim]

those junction boxes are handy and super easy to drill and tap for pipe/emt. I used one to recreate the start switch on my unisaw, couple buttons off ebay and the box was <$20 total. I just sawed the ears off with the bandsaw and drilled where I needed. I think it would work fine in your situation.

 

[Marctrees]

Just keep in mind the PVC boxes such as Carlon brand are much easier to work with compared to Steel.

They are not available in as many size options as Steel Hoffman, but enough sizes where you will find one suitable.

Marc

 

[wyliesdiesels]

Thought about the LB approach into the back of the junction box but as I said in the first post, the cover on the LB would be towards the wall interior and not accessible. Not sure I could feed the cable thru without the LB's cover removed to make the turn.

Get an LL or LR conduit body.

 

[larry4406]

Get an LL or LR conduit body.

I don’t see how this helps as it would be in the wall behind the enclosure and still not accessible.

 

[Marctrees]

Wylies has historically shown to be a very smart and very helpful Guy.

A Poster explains his situation to the best of his unique ability, and we all perceive different things.

The problem is communicating over interweb text which is limiting in many ways.

Marc

 

[larry4406]

Wylies has historically shown to be a very smart and very helpful Guy.

A Poster explains his situation to the best of his unique ability, and we all perceive different things.

The problem is communicating over interweb text which is limiting in many ways.

Marc

I agree 100%.

Wylies provides exceptional knowledge and I value his contributions. I googled the LL and LR conduit body images and could not understand how this would help me. Maybe I’m missing something.

 

[Marctrees]

You, being the OP, knows your specific detailed situation and all the nuances of what may be a solution, or not, better then anybody else.

And, there could be ten logical variations of solution.

Tell ten Carpenters basic parameters to build a shelf, you will get ten varying end results.

Also, not saying in THIS case, but MOST people do not read posts better than a Kindergartner... in MANY cases.

Either busy in a rush, or just plain very poor cognizators.

I just made a new word I think !!



Marc

 

[Fasthotrod]

Fasthotrod - Awesome well presented solution.

A variation of what I mentioned, but beautifully explained.

Dead serious.. I'm not the OP.. but Thank You.

Marc

Thanks! Just figured it might be easier to explain myself with a few diagrams... and I got a little carried away.

Wow, FastHotRod, nice drawing and good design. It isn't anything that I need, but i appreciate the work that you put into it.

Thanks for the kind words.

I am getting ready to build, do you do details like that on a contract basis???

No, not really... my 'normal' job keeps me pretty busy, and I'm in the process of getting my shop built so it's taking up a lot of my free time. I suppose I need to start a thread about that in the other section sometime soon.

Mark

 

[wyliesdiesels]

I agree 100%.

Wylies provides exceptional knowledge and I value his contributions. I googled the LL and LR conduit body images and could not understand how this would help me. Maybe I’m missing something.

I couldnt really picture your situation and just thought that if an LB cover was inaccessible, that maybe an LL or LR cover would be.

Have any pics of your install?

 

[larry4406]

I couldnt really picture your situation and just thought that if an LB cover was inaccessible, that maybe an LL or LR cover would be.

Have any pics of your install?

Thanks wyliesdiesels. Haven't started the install. Here is the sketch again from the first post and Fasthotrod's sketch from post 13.

Exterior 2x6 insulated wall. The interior wall surface is fully finished (bathroom). Accordingly, I would remove siding for this installation then put it all back together.

I would like to have the conduits in the wall from the attic entering into the top of an enclosure. Then the enclosure is extra deep. This extra depth then allows conduits to then go into the earth. The wire then makes an S-turn/zig-zag. All this to avoid conduits being fully surface mounted on the siding from the earth to the soffit above. The icing on the cake would be for the special enclosure to have an integral nailing fin (like a vinyl window) for attachment and flashing.

As the enclosure would be let into the wall from the exterior (with only its access cover on the exposed end), access to the back or sides of the enclosure (within the wall cavity) is not accessible. Thus any LB, LL, LR solution that enters the rear or sides of the enclosure within the wall cavity would not work. Initial installation would be one conduit for the feed to my barn. The other conduit would be for a future whole house generator.

Fasthotrod's sketch is exactly what I am contemplating minus the integral nailing fin as it appears that this type of box is not made. I guess I could use Protecto-wrap or similar to first seal the enclosure perimeter to the wall sheathing, then install J-channel around the enclosure, flash this J-channel nailing fin, and OSI -Quad caulk the J-channel to the enclosure.

Alternately, I mount the enclosure at another location where I have rear access to the enclosure (unfinished basement) but this will add about 60' to the wire run.

 

[Bert_]

I couldnt really picture your situation and just thought that if an LB cover was inaccessible, that maybe an LL or LR cover would be.

Have any pics of your install?

My take on it was he wants to bury the LB inside the wall and ****** into the back of the junction box which would be on the outside of the wall, ie no access to any part of the LB once it's put together.

If that's the case, not kosher. It has a cover for a reason and it needs to remain accessible after the install.

 

[larry4406]

My take on it was he wants to bury the LB inside the wall and ****** into the back of the junction box which would be on the outside of the wall, ie no access to any part of the LB once it's put together.

If that's the case, not kosher. It has a cover for a reason and it needs to remain accessible after the install.

Bert - yes my thinking exactly hence why I’m puzzled.

 

[Radix2]

Can't see the need for inside conduit on the SER inside a finished wall.

Surface mount your box, SER in the back, conduit out the bottom, keep your wall insulation and sheathing intact.

 

[larry4406]

Can't see the need for inside conduit on the SER inside a finished wall.

Surface mount your box, SER in the back, conduit out the bottom, keep your wall insulation and sheathing intact.

The generator whole house feed is a problem for another day thus the desire to have the conduit in place. Also, zero access to the back of the enclosure once the enclosure is installed.

 

[PT Doc]

Wiegmann makes all kinds of exterior boxes. You want a model 121208 or 121210 or 121212. I got mine from Zoro.

 

[Elkjunkie]

I went with the amateur and poor- utilizing my existing LB for my pump house feed to get in the panel

 

[Bert_]

I went with the amateur and poor- utilizing my existing LB for my pump house feed to get in the panel

Nothing amateur about that. Looks good in my opinion, well thought out except that coupling right below the box. Less holes in the wall too.

Technically that box might be too small but not something I would worry about at this point.