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Small Cabin Forum / Cabin Construction / Help w/ bringing power to the cabin
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WILL1E
Moderator
# Posted: 22 Oct 2021 10:24
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Looking for guidance on bringing power into the cabin so i can keep working on it through the winter. Since my budget is running low i want to do this myself. I don't have issues doing electrical as long as i know what i all need to have for it to be done right. I have a guy that's willing to look at everything when i'm done to give it his blessing and sign off as the electrician.

So i have 200 amp service going to the power pole/meter base i built that's about 30-40' from the cabin. On there i have a 125 amp panel. I would like to run a 100 amp circuit to power the entire cabin.

Aside from the main 125 amp breaker, i have a 20 amp circuit going to the GFCI below the panel and 50 amp circuit going to the plug (also below the panel) that services the camper currently. Pretty sure i need to keep the 20 amp plug below the panel per code. I would like to keep the 50 amp camper circuit for now until spring when we discontinue the use of the camper and sell it.

1. So i need to know what wire i need to run 100 amps to the cabin?

2. Since i need to keep the 20 amp circuit and termporaily need to keep the 50amp camper circuit, should i only put a 75 amp breaker on the line going to the cabin or would i be ok putting the 100 on right away knowing i'm not going to pull anywhere near full capacity until the camper is gone?

3. How far down do i need to trench the wire to the cabin?

Keep in mind the cabin floor is about 2-3' off the ground. I would like to either put the panel in the 1st floor bedroom or bathroom. Not sure the bathroom is a good idea or allowable, so i guess the bedroom it is. Anyways, i would prefer it to be on an interior wall, however i won't be able to trench under the cabin to directly below where the panel would be. So would i have the conduit radius pop out of the ground at the outside wall, and run conduit up to the bottom of the floor joist and then run across the bottom of the floor joist to the point where it would go up through the floor to that interior wall?

I guess i'll stop the questions there for now and once i have this info i can keep moving on.

Nate R
Member
# Posted: 22 Oct 2021 10:47
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I believe my electrican had to run 3 AWG copper to the 100A panel inside the cabin. Very similar to yours, from a panel outside to the cabin, but more like 60 feet. You're fine with a 100A breaker in the outside panel.


I THINK you have to go down 24". Mine was done in plastic conduit. Also, I think he had to run a ground wire between the panels, AND drive a ground rod at each panel location, too.

WILL1E
Moderator
# Posted: 22 Oct 2021 10:52
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Thanks Nate! So he ran 2 hots, 1 neutral and a ground wire?

I have 2 ground rods spaced 6' apart at my current panel, but i assumed i'd have to do the same again by the new one as well.

gcrank1
Member
# Posted: 22 Oct 2021 11:03 - Edited by: gcrank1
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I am not an electrician (end of disclaimer).
Imho.....since Im still 'in process' and not totally finalized on a number of 'wiring details' and not wanting to spend money and work time going a wrong direction.
Im totally off grid. My 'power-house/tool-shed is 90' from the cabin. I run my 2000w inv/gen from there only when needed as well as the solar inverted to 120vac.
I have run a 700w microwave alone in the cabin without a hiccup as well as an old 1000w 30cup perc as a water heater and a toaster together off the gen.
All on 100' of 12ga contractor type ext. cord to an RV/marine type inlet.
That is wired to a small 2 fuse c/w throw power box (as my subpanel) temp mounted inside so I have convenient power control and access To the fuses.
That wired to my outlets (led lighting is run off an outlet)
Fwiw:
At this point of construction at your place Id be doing the same thing if I had your ped using the 20a outlet to run 30-40' distance with a 50' 10ga. ext cord. Good to go with the GFCI.
Do you know yet what the regs are for running 'real wiring' from the ped into the cabin?

Nate R
Member
# Posted: 22 Oct 2021 11:23
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Yep, exactly... 2 hots, neutral and ground.

gcrank makes a good point....if you've got that 20A recep there..... ( Mine does not)... could just run a 10 or 12 AWG extension cord for now!

Tim_Ohio
Member
# Posted: 22 Oct 2021 12:00 - Edited by: Tim_Ohio
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Sorry to disagree, but you only need two hots and a neutral from your main drop. At the cabin, you will have to install two ground rods no less then six feet apart and at least 8 ft deep, unless you have rock. Then, you would go down as far as you can, bend the rod 90 degree and lay it in a trench. Connect both to #8 copper and connect it to a separate ground bar in your cabin box. You will have to have a second bus bar not unlike the one for the ground, but separate from it. You will connect the neutral from your main to it and all neutrals in the cabin will be connected to it. You will not connect the ground and neutral (bond) them in your cabin. At each location, you will need a 100 amp breaker (if that's what you choose). One on the main to serve the cabin and one in the cabin to serve as the main disconnect in the cabin. I recommend going over in the cabin with 20 amp breakers and 12 gauge wiring throughout. Use plastic boxes to reduce chance of some kind of short. Oh, and that distance should require #2 wire underground for 100amp breakers. You may never get close to that draw, but any future occupants won't ever have a problem.

Tim_Ohio

Tim_Ohio
Member
# Posted: 22 Oct 2021 12:03
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Oh, I also forgot to specify that the underground is aluminum and all of the wiring will likely be black. So, at the main, in the box, you will tape one of the three wires with white tape to indicate it is your neutral. You will also have to tape the other end of the same wire in your cabin box with white tape to indicate it is the neutral in that location as well.

Tim_Ohio

Tim_Ohio
Member
# Posted: 22 Oct 2021 12:09
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Oops, also forgot to tell you, it is necessary to coat the ends of the aluminum wire with antioxidant paste to prevent corrosion under the lugs. This is very important.

Tim_Ohio

Tim_Ohio
Member
# Posted: 22 Oct 2021 12:19
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Of course, if you chose not to do a 100 amp service, the gauge of the wire would be smaller. Just don't try to put #2 in smaller breakers, because the lugs will not be large enough to accept the diameter of the stranded wire. I've seen idiots have a 100 amp at the main, then put a 50 amp breaker at the sub panel, then cut off some strands of the #2 wire they used to get it to fit into the lugs.

Tim_Ohio

Brettny
Member
# Posted: 22 Oct 2021 12:21
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Essentially you will be running your cabin as a sub pannel and need 4 conductor wire not 3.

Use a 100a breaker at your power pole/main pannel and get a 100a pannel for your cabin. Use conduit for the above ground parts but that's all. Use direct burial wire.

Everyone dreams that if your wire goes bad in conduit you can just pull a new wire in and with direct burial wire you cant and that's true. But direct burial wire is so tough you more than likely will never need to. I have 100a buried right through my driveway and have had for years.

Tim_Ohio
Member
# Posted: 22 Oct 2021 12:25
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I'm sorry, I have to correct myself.

"Sorry to disagree, but you only need two hots and a ground from your main drop" This should have said,
"two hots and a neutral".

Tim

travellerw
Member
# Posted: 22 Oct 2021 13:53
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I would check the codes on depth.. They are different in different parts of the country.. They are also different if the area will have ANY vehicle traffic (even once a year).

Tim has given great information. However, I will note about the grounding rod. Up here it has to be an actual grounding rod and not a piece or rebar. You need to go to an electrical supplier (like Eecol) to get it. 8ft down is a long way and depending on your ground it can be a bugger to get it down there. Pretty tough to drive that far by yourself with a sledge (not impossible though).

I will also second the direct bury cable. Its good stuff (but be prepared for the price). Also if you go with conduit and conductors, you will probably have a hard time buying just the length you need. Cable of that size is mostly sold in bulk. You can usually find direct bury sold by the foot.

Good luck.. If it was me, I would do my best to find an electrician willing to make a deal.

WILL1E
Moderator
# Posted: 22 Oct 2021 14:10
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Quoting: Nate R
gcrank makes a good point....if you've got that 20A recep there..... ( Mine does not)... could just run a 10 or 12 AWG extension cord for now!

Already doing this for general power in the place. Not sure i'd want to do that for powering the pellet stove even though it only specs 5 amps for starting and 2 amps for running.

My Home Depot sells some wire by the foot and i think Menards does as well for the heavier stuff, so i'll have to see what they have available.

Tim_Ohio are you an electrician?!

Tim_Ohio
Member
# Posted: 22 Oct 2021 14:27
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Willie,

No, I'm not an electrician. I've just studied enough and done enough and had enough of it inspected after the matter. My father-in-law worked for AEP electric company and worked with me on a number of projects.

I might mention, #2 AWG wire is not easy to work with. Try to avoid sharp bends in the conduit you use as entrance into the cabin. You should be able to use sweeping bends and then straight up into the bottom of your box. It's not fun to run it through conduit in different directions, by the way.

Also, know that 100 amp is a lot of power. I'm going to assume you plan to run a number of 240 volt appliances, such as possibly 240 volt air conditioning or maybe an electric range or maybe an electric water heater or maybe a well pump or maybe an electric furnace? These are the main reasons to have that much power. Otherwise, you could get by on a lot less and install cheaper wire and service panel.

Tim_Ohio
Member
# Posted: 22 Oct 2021 15:01 - Edited by: Tim_Ohio
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Willie,

This is one of the best videos( see link below) I've seen for doing your own electrical panel. This guy is an electrician and his technique is excellent for doing a service panel. Keep in mind, though, he is installing a main panel and his grounds and neutrals are on the same bus bar. In your case, you will have to have a bus bar screwed into the box, off to the side for all of your ground wires. Only your neutrals will go to the neutral bar. Your panel is a sub panel, not a main. If you look at my posts, there is a picture of my panel which shows the separate bars I put on each side of the panel. I really only needed one, but did not want to run wires around the other side. I also, have four more breakers I can install in this box if needed in the future.

Note that the green screw laying on the bottom of the box is not in place to tie the box to the grounds and thus the neutral. This is how it should be on a sub panel when power is coming from a main service, like you're doing. I actually installed that screw when I finished the installation because I do not have power from a main service at this time. I have a generator that runs the service and because it is consider a main service, using just a generator, it is installed.

Here is a video:

https://www.youtube.com/watch?v=Hw9e3HW6XVU


Tim_Ohio

Tim_Ohio
Member
# Posted: 22 Oct 2021 15:11
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Willie,

Here is a 100 amp electric panel in my cabin. I did not have a 100 amp service from my generator, so I removed the 100 amp breaker and installed a 60 amp breaker. I have a generator that will power up the cabin with 240 volt, 50 amp service. I do not use it, but set everything up so that I could either use it or later, bring in power from a main service.

Note that the ground wires are only on the separate bars screwed into the box on each side. The neutral wires are wire to the neutral bar just under the breakers.

Tim_Ohio
electric panel
electric panel


WILL1E
Moderator
# Posted: 22 Oct 2021 15:29
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Thanks for all the info!

Ill have to take a photo of how my main panel is right now for reference.

As for appliances, i'm on the fence what to do. We will want/need a fridge, microwave, stove and water heater. I'm not sure if i should mess with looking into a propane tank to deal with the stove and water heater, or if i should just stick with electric for it all. Since the cabin is being built as a "dry" cabin, i won't have any water in till after it's inspected. At that point i'll either connect in a sand point well or run off an IBC that i bring up from home. So ideally i would put in a tankless system...TBD though.

For A/C, i would either do one of those in room units that sits on the floor and vents to a window, or i would look into a wall mount unit or window unit.

Nate R
Member
# Posted: 22 Oct 2021 15:53
Reply 


The weird thing is, and what seems to be debated online, is whether this IS a subpanel or not. Seems AHJs have the say sometimes in these situations on whether a ground wire is needed back to the meter panel, and how this is looked at.

Also, I believe my electrician lobbied for a 60A panel/feed, but the inspector said that she was considering my place a dwelling, and needed 100A minimum. I'll have to look more closely at how my ground/neutral bond is done in that panel, or if that's why I have a separate ground wire.

-Nate

travellerw
Member
# Posted: 22 Oct 2021 18:05
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Just out of interest I looked at my local code. 100A service requires an electrician and is not allowed to be installed by the home owner (will not pass inspection). The cutoff is 100A in our code book (99 you can do yourself). You might want to look that up if you are having everything inspected.

In my case, I have no option as the closest power is about 1.5 miles away. However, even if it was there, I would still go with propane for cooking and dual for heating water.

Brettny
Member
# Posted: 22 Oct 2021 21:20 - Edited by: Brettny
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Quoting: Tim_Ohio
I'm sorry, I have to correct myself.

"Sorry to disagree, but you only need two hots and a ground from your main drop" This should have said,
"two hots and a neutral".

Tim

Then if you ever had a short to ground you would be relying on your ground rod and connections to trip the breaker. This could mean your metal siding, plumbing or anything else metal could have 120v on it...and you could be the good ground path. You dont connect your boxes or anything else metal to the neutral so there would be no path to ground, unless you make it.

That's not code here and poor practices.

I have also put in a main pannel and sub pannel my self and had it inspected.

gcrank1
Member
# Posted: 22 Oct 2021 22:35 - Edited by: gcrank1
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I like cooking over a flame, grew up with a propane stove. Had one elec stove at a rental for 4yrs and never warmed up to it. My wife likes having the small microwave and toaster which we run off the quiet little inv/gen. Well, I like em too.....
We use 'pane for the 2 wall furnaces (an 18k btu 'blue flame' and a 30k btu infrared, opposite sides in a 16x24, cozy) as well as for the outdoor cooking gear, so having it for the inside range makes sense.
What are you going to use for cabin heat?
I have a 250# bulk tank, a pair of 30# and quad of 20# cylinders. Had to run the piping, manifolds, drip legs and valves......that is a lot of pipe!
If you are good with an elec range, and since you have grid with no other need for bulk LP, it makes sense to go 240vac. Wiring will go easier and faster.
A small AC 'window unit' mounted up high in its own opening will be out of the way and the cold from it will sink into the room nicely while it conditions the warm air higher in the cabin. Id put it on the shady side.
We have had an elec water heater at home for 35ish years. I replaced it about 4 years ago, went from a 45ish gal to a 30gal. From ground water temp to shower ready took 20min! The 2 of us can each do our shower and not run out of hot. The recovery time on the less amount of water in tank is pretty quick.

Aklogcabin
Member
# Posted: 23 Oct 2021 09:32
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Hello. You will need under ground rated burial wire. It will have 3 wires one is marked with a line. That is your neutral. Other 2 are hot and go to each side of the breaker box respectively. So your 20 Amp breaker will be connected with a hot and neutral. A separate ground bar must be purchased and screwed into your breaker box. Your 4ga copper ground wire will connect this to your ground rod. Use dielectric paste on the bare wire in the connection.
As per coming up to the cabin. The ditch needs to be 2 feet deep. Bed the wire by hand as to not have large rocks near. As it comes up you will need to have it in conduit. If it were mine I would come up with a sweep to a section going straight up into the box on an outside wall. If you want it on an inside wall you will have to dig it out until you can turn up to go to breaker box but bending that wire is hard. As it has to be in conduit from the 2' below ground until it connects to the box.
From start ditch 2' from your current supply to the cabin. Lay in the buried service wire. You need to slide the conduit over the end of the wire n feed through. You need conduit on both exposed ends. When you buy the conduit you will need to but the conduit end scuff guards n breaker box hub connectors.
So put the conduit on and installed before burying.
Your inside box will be wired just like the one outside.
I would go with the electrical water heater n a propane stove. BTW code will also want a 220 Amp service n plug in for an electric stove wether you use it or not. So you will need to pull a 10ga wire to behind the stove for it.
This is pretty basic electrical hook up. Any how to wire your home book should have the information you need. And pictures, pictures are good.
Good luck man, I like your inthusiasim. Not a quitter. You can do this stuff

gcrank1
Member
# Posted: 23 Oct 2021 10:50
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I have a 50+' length of 10 ga. UF (undergrd feeder) 3 wires + grd waiting in the tool shed potentially for my end-game wiring.
I had to dig it out by hand in hard pack fine sand from about 1' down.....no way Im going to be digging a 2' deep trench! So, I recommend checking price on a trencher rental locally.

Tim_Ohio
Member
# Posted: 23 Oct 2021 20:14
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Will1e,

You know, I’ve been thinking about your electric. You are in a great situation since you have service from a utility company. I regret suggesting you use a smaller breaker and wire. Install the 100 amp feed. You can do whatever you want with that much power. I have an electric on demand water heater in my barn shower, for example and the bathroom it is used in has baseboard heating. Since all of the plumbing and the water line feed comes into that bathroom, I’m able to use it all year without worrying about it freezing. That’s just an example. You wouldn’t need any propane if you didn’t want to plumb that. I kind of envy you. I have to run off of a generator or battery at my cabin, since it’s to far from utility service.

Go for it!

Tim_Ohio

gcrank1
Member
# Posted: 23 Oct 2021 20:41
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Just think, having elec heat you could have it 'call ready' so a day before going there in cold weather you could ring it up to turn on and bring it up to a comfy temp before your arrival!

travellerw
Member
# Posted: 24 Oct 2021 18:05 - Edited by: travellerw
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Quoting: gcrank1
Just think, having elec heat you could have it 'call ready' so a day before going there in cold weather you could ring it up to turn on and bring it up to a comfy temp before your arrival!


You could do that with Propane too.. Actually it might be easier since the thermostats to do that are on the shelf at HD. I'm sure they also exist for electric heat, just not as available.

I think the OP mentioned a pellet stove.. It wouldn't be hard to automate that either, as long as you leave the hopper full!

Nate R
Member
# Posted: 24 Oct 2021 20:16
Reply 


After getting my 3kw electric wall heater put in this weekend and running, I agree....put in the 100A!

Nice to have that on a thermostat....and not lugging propane for heat.

WILL1E
Moderator
# Posted: 25 Oct 2021 09:29
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Thanks for the help so far fellas!

What are the "rules" about where the panel can be located? I was going to put it on the exterior wall of the bedroom, but i didn't want it sticking out like a sore thumb the second you walk into that room. So i was going to put it on the wall that the door is on for the bedroom...but i understand the benefits of keeping it on the exterior wall.

So the only other spot would be in the bathroom. Plan to do a compost toilet and at some point a corner shower. Layout in there isn't finalized. But is the bathroom even an option?

I would think having the panel on an interior wall would be more ideal due to lack of insulation. But trenching under the cabin would be a nightmare.

FYI, when looking at the floor plan, my power pole is up and to the left of the top left corner of the cabin floorplan.
16x32floor.JPG
16x32floor.JPG


ICC
Member
# Posted: 25 Oct 2021 10:00
Reply 


Why not use a panel designed for use on an exterior wall?

No bathrooms. No closets. Must have free space to stand in front of it. The NEC rules on panel do make sense from safety and ease of future needs for servicing.

Outdoors you can place almost anywhere. It is easiest when there is an attic as wires can then be dropped from attic down walls. But still workable.

travellerw
Member
# Posted: 25 Oct 2021 10:29 - Edited by: travellerw
Reply 


Sigh.. Yup I'm struggling with the same issue and have been looking at options..

1. Outside (in a small box built on the wall) - Local code only allows this in certain conditions and its up to the inspector to asses and pass on an individual basis!

2. Outside wall - No matter what it will be a cold spot in the insulation. Not only will the box take up insulation space, but the conduit going up to it is a cold path.

3. Bathroom - Nope nada, won't pass up here.

4. Under the stairs (mine are similar to yours) - I'm still looking into it, but it looks like trenching once under the cabin is not required. Once you are under the structure you can come out of the ground and secure to the bottom of the joists. However, this option uses more wire (both on supply and interior).

5. Shared interior wall between bathroom and bedroom - Not super keen about the box backing onto a wet wall. Same cold conduit issue (could spray foam from the bottom, but then the conduit would be plugged for any future service).

So in my cabin I'm probably going to go under the stairs as its out of sight and any cold issues are in a non living space! I have reattached your picture with the spot I would try for in your cabin.
149793_1_o.jpg
149793_1_o.jpg


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