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Small Cabin Forum / Cabin Construction / Help w/ bringing power to the cabin
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Nate R
Member
# Posted: 25 Oct 2021 11:27
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FWIW: Mine is on an exterior wall. We plan to cover it with a framed picture...Wish our electrician had mounted it a bit higher like we asked....

Anyway, with the 2x6 walls, the panel is 3.5" deep...I can JUST slide 2" foam behind it.... so I think I'll probably insulate behind it with XPS foam, and bring wires out the top and bottom. (I've only got 8 coming out total.

ICC
Member
# Posted: 25 Oct 2021 13:02 - Edited by: ICC
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Yes, the rules can be different in different locations.

Here, under or over stairs are not allowed IF the under location means stooping or kneeling to access.

By exterior box I mean the weather resistant type that surface mount on the exterior wall. These are common here. Probably half the homes in town use external panels.

The normal thing is to run external conduit up the wall and into the attic space. Placement on gable end wall works best. We would use Carlon pvc conduit with a type LB 90 degree fitting to turn the conduit through the wall. When there is a second story or loft floor place that conduit in the floor joist space. Insulation reduction is minimal to non existent.

ICC
Member
# Posted: 25 Oct 2021 13:09
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Small exterior service panel on exterior wall of a friends cabin.
Panel
Panel


WILL1E
Moderator
# Posted: 25 Oct 2021 15:45
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So if i put the panel on an exterior wall in the bedroom, can i come up on the inside of the outer most floor joist and up through the bottom plate below the panel to avoid going through the wall and disrupting the siding?

ICC
Member
# Posted: 25 Oct 2021 17:16
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With an elevated pier and beam foundation you could even go down from the service panel, under the floor and up inside the wall framing. That would need LB type fittings with removable cover plates at each 90 degree bend but could be done.

Romex is not supposed to be used inside conduit, but that can be adjudicated by the inspector. Our usual inspector allows it in special cases if the conduit is well under-filled. Conduits are rated for so many conductors of so many amps. I'm not an electrician so don't know the numbers off hand. Romex is not supposed to be in conduit as the extra layers of sheathing slow the heat dissipation. Using fewer wires/amps per conduit size can be allowed by the inspector, the AHJ. Ask first.

travellerw
Member
# Posted: 25 Oct 2021 20:33
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Damn.. I wished out inspectors were more lenient. I called and was told the absolutely wouldn't pass an external box in a single family dwelling. The only time they pass them is when its a rental where the box is installed outside with access to both tenants (like under a covered deck).

As to under the stairs. The spot on his drawing is has standing room. Same as mine.

WILL1E
Moderator
# Posted: 26 Oct 2021 08:15
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So it sounds like once i put the box inside the cabin on an exterior wall, i will have at least 3 wires plus the ground wire feeding out of the cabin. What size conduit will i need to handle all these wires?

I ask because i think i might just do the extension cord thing for now. But if i'm going to drill a big hole through my bottom plate, i want to drill it to fit the conduit right away so that i'm not drill another hole later or having to enlarge it.

WILL1E
Moderator
# Posted: 26 Oct 2021 08:21
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My Menards sells alot of wire by the foot.

Which stuff do i need?

https://www.menards.com/main/electrical/electrical-wire-cable/electrical-service-wire -cable/c-1525874617506.htm?queryType=allItems&Spec_RecommendedEnvironment_facet=Outdo or&rid=DMRQMcUeMv

gcrank1
Member
# Posted: 26 Oct 2021 09:51
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Ive seen 'contractors boxes', a weatherproof self contained box of outlets and I assume circuit breaker(s) and GF that has a pigtail to plug the heavy duty ext cord to. Ive thought such could be handy about my place and think that while under construction it may give some leeway for you to 'finalize your interior wiring plan'.
Fwiw, in decades past we used simpler, but less safe, diy extension boxes, basically a heavy duty version of a 'power strip'. I expect they are not 'allowed' any more.....

Tim_Ohio
Member
# Posted: 26 Oct 2021 09:51
Reply 


WILL1E,

Did you decide what service you want to run? Maybe I missed what you decided. Did you decide if you are putting it all in conduit?

In any case, here is an interesting video that might help with the conduit part, if you so choose to run it in conduit:

https://www.youtube.com/watch?v=HRc5sH2ZU2M

Also, if you run conduit, remember the expansion fitting for frost heave, it might be part of your code:

https://carlonsales.com/techinfo/installationtraining/IT-ISEXPJT.pdf

Tim_Ohio

WILL1E
Moderator
# Posted: 26 Oct 2021 10:45
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gcrank1 I'll have to see if i can find more about those.

Tim_Ohio I want to run 100 amps. I'd prefer to do direct bury just because i'll be navigating the wire through the woods and around trees.

Tim_Ohio
Member
# Posted: 26 Oct 2021 11:35
Reply 


WILL1E,

This looks like the correct wire:

https://www.menards.com/main/electrical/electrical-wire-cable/electrical-service-wire -cable/aluminum-urd-cable-2-2-2-per-foot/3692130/p-1473854610604-c-1525874617506.htm? tid=-32567146484849045&ipos=7

Then, you will need two 8' copper clad ground rods and the #6 bare wire and two clamps. Without cutting the #6 wire, you will connect it from one
ground rod to the other, then drill a small hole below where the panel is located and run it into the building along a stud. Staple it to the stud and run it through a plastic clamp in one of your knockouts. Connect it to your ground bar. Then all of the grounds in the cabin are to be connected to that bar or bars, that is if you decide to install a second bar on the other side of the panel, it will be grounded to the first by the connection to the box via the screws.

Your conductors and neutral in the 3-wire #2 go through the short bit of 2" conduit you will install, where the cable comes to the cabin. I'd put a sweeping bend in at that point. If you want to make it easy, go through the floor, and then right up under the box. Then there will not be a right angle to pull it through.

Oh, you will need a bit of 2" conduit at your service main to come out of that box with a weather-tight connection going down and into the ground with a sweeping bend. It should be possible to come out the bottom of that box.

I think you said you will be having this inspected. So, that inspection will tell you if you did anything wrong and then it can be corrected as per their code.
I don't foresee there being any problems that will require major changes. They may like to see the depth of your trench before you back-fill. You might want to check on that.

Nate R
Member
# Posted: 26 Oct 2021 11:52 - Edited by: Nate R
Reply 


I'll reiterate that my run has a ground wire between the main panel and the cabin panel, as well as ground rods at both panels.

I believe this is code for a subpanel as of the 2008 NEC.

So, if 2 AWG AL wire is OK for 100A, then I'm assuming this would be needed: https://www.menards.com/main/electrical/electrical-wire-cable/electrical-service-wire -cable/2-2-2-4-aluminum-mobile-home-feeder-per-foot/

Tim_Ohio
Member
# Posted: 26 Oct 2021 12:12
Reply 


WILL1E,

+1 on what Nate is saying. I stand corrected. His input made me look into it. It is now required by code, to install the ground from the main panel to a sub-panel with the conductors and neutral. It is still necessary to install the ground rods and to tie them to the ground from the main.

I support his argument for the wire he suggests.

Thank you Nate.

Tim_Ohio

Tim_Ohio
Member
# Posted: 26 Oct 2021 12:40
Reply 


WILL1E,

Here is a little more:

"The current state of this section was reached in the 2008 NEC, which forbade new construction from using the feeder neutral to provide ground for the fed system. (Your choices now are to provide a separate ground wire, which is what is normally done, or use a distribution transformer to create a separately derived system for the fed building, which has its own N-G bond.) Many of the installations that fall under the current exception were installed prior to the 1999 NEC, which is the first edition that forbade parallel current paths between the structures involved."

Apparently, running the ground from the main is a lot less expensive then having to install a distribution transformer. And, in the past, there were some installation where the neutral was bonded to the
ground in panels in the sub-panel installation in a separate building without the separate ground bar
(the way a main panel is sold)

So, just remember not to bond (join) the ground and neutral in your sub-panel located in your cabin. To accomplish this, you will not install the green screw provided with the panel that is screwed into the hole located at the top of the panel and goes through the connecting neutral bar to the metal box. They are only to be bonded in on circuit which is the main you are coming off of.

Tim

WILL1E
Moderator
# Posted: 26 Oct 2021 12:50 - Edited by: WILL1E
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Nate R link isn't working, i get a menards error page.

Nate R
Member
# Posted: 26 Oct 2021 13:05
Reply 


https://www.menards.com/main/electrical/electrical-wire-cable/electrical-service-wire -cable/2-2-2-4-aluminum-mobile-home-feeder-per-foot/3692059/p-1473854610601-c-1525874 617506.htm?tid=1865184504019720366&ipos=2

Tim_Ohio
Member
# Posted: 26 Oct 2021 13:06
Reply 


I think Nate was referencing this stuff:

https://www.menards.com/main/electrical/electrical-wire-cable/electrical-service-wire -cable/2-2-2-4-aluminum-mobile-home-feeder-per-foot/3692059/p-1473854610601-c-1525874 617506.htm?tid=4156221390087864445&ipos=2

It adds the ground and is direct bury.

Tim

snobdds
Member
# Posted: 26 Oct 2021 13:12
Reply 


Hire an electrician...

WILL1E
Moderator
# Posted: 26 Oct 2021 13:17
Reply 


Thanks fellas, link works now!

I found some old photos of my power pole. Looking at the first photo, the cabin is to the left. Since there are no large knockouts left on the bottom left side of the box, i'll either need to use that large one on the left side or the back left side....the later being the better option because the conduit would run flush down with the 6x6 treated post.



This was a photo of the wiring while i was building it in my garage before it was 100% done.


WILL1E
Moderator
# Posted: 26 Oct 2021 13:26
Reply 


Quoting: Tim_Ohio
Without cutting the #6 wire, you will connect it from one
ground rod to the other, then drill a small hole below where the panel is located and run it into the building along a stud. Staple it to the stud and run it through a plastic clamp in one of your knockouts. Connect it to your ground bar.

Since i have ~2' from the bottom of the floor joist to ground level since my cabin is elevated, can the ground wire going to the ground rods be connected to the outside of the PVC going into the ground?

Tim_Ohio
Member
# Posted: 26 Oct 2021 13:52
Reply 


WILL1E,

Do you have a disconnect outside the main panel? If not, when you go to install your new feed, temporarily put cardboard over any of the hot areas in the panel. Even professionals will do this to prevent an accident. The number two wire is very stiff and will require some work to get it into place.

As for the ground wire, I don't see why you can't run it along the outside of the PVC. Maybe zip tie it or use electrical tape every so many inches. Remember to not bury the tops of the ground rods. The connection point with the clamps needs to be visible for inspection.

Tim

WILL1E
Moderator
# Posted: 26 Oct 2021 13:55
Reply 


Quoting: Tim_Ohio
Do you have a disconnect outside the main panel

The breaker in the photo at the top right is the main disconnect.

Tim_Ohio
Member
# Posted: 26 Oct 2021 14:04
Reply 


Remember, though, even with it off, the two wires and the lugs are hot. You will need to keep from contacting them in any way. So, take a piece of cardboard and tuck it behind that green ground wire and the breaker after you turn it off.

Tim

Tim_Ohio
Member
# Posted: 26 Oct 2021 14:11
Reply 


If you want to be safer about it, you can always have the electric company come out an pull the meter.
Then, have them reinstall it after you complete the work. That way you have no hazards to worry about. There may be a fee.

Tim

WILL1E
Moderator
# Posted: 26 Oct 2021 15:11
Reply 


Yup, never can be to safe!

WILL1E
Moderator
# Posted: 27 Oct 2021 15:25
Reply 


So 2" PVC conduit will be sufficient for the the aluminum 2-2-2-4 wire ya'll spec'd out at Menards above? Just confirming so i know what size hole i'm going to drill in my bottom plate this weekend for the extension cord.

Tim_Ohio
Member
# Posted: 27 Oct 2021 15:56
Reply 


Menards lists the actual outer diameter as 2 3/8 in for schedule 40, trade 2 inch diameter:

https://www.menards.com/main/electrical/conduit-conduit-fittings-raceways/conduit/pvc -conduit/3652280/p-1444427701169-c-6423.htm?tid=-6092114833321678290&ipos=4

You can go up to 6-AWG #2 wires in 2 inch schedule according to this chart:

https://www.elliottelectric.com/StaticPages/ElectricalReferences/ElectricalTables/Con duit_Fill_Table_PVC.aspx

WILL1E
Moderator
# Posted: 2 Nov 2021 08:41 - Edited by: WILL1E
Reply 


11/2/2021 UPDATE

Stopped at my second home last night (Menards...serioiusly, i feel like i live there lately). I picked up my 100amp breaker panel and scored 100 feet of the 2-2-2-4 for $140. Way more than i need but i'll find something else to use it for or sell it. The wire is smaller and more flexible than i expected so i got 1.5" PVC fittings. The 2" conduit looked waaaayy overkill.

So i'll come out the back of the existing panel with 2 hots a neutral and a ground to a LL conduit body , then straight down the pole into the ground inside the PVC pipe and into the sweep. Once out of the sweep i'll run the wire in the dirt up to below the cabin. Then it will go into a pvc sweep, then into straight pipe up through the bottom plate of the cabin wall and into the new sub panel. I'll use male terminal adapters at both boxes with those rings (can't think of proper name) on the insides of the boxes. Also at the new panel i'll run a copper ground wire out it's own knockout, down along the stud wall and out the bottom plate to the ground rods. Oh, and don't install bonding screw in new panel since it's already in on the original panel. Sound right for all of this?!

Tim_Ohio
Member
# Posted: 2 Nov 2021 09:06
Reply 


Sounds good to me.

Tim_Ohio

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