Small Cabin

Small Cabin Forum
 - Forums - Register/Sign Up - Reply - Search - Statistics -

Small Cabin Forum / Off-Grid Living / Wiring cabin for generator/solar?
Author Message
Klicky1
Member
# Posted: 5 Dec 2011 21:16
Reply 


I have a small cabin, no power. The previous owner wired the cabin I "assume" to run off a generator. There is a receptacle outside that I "assume" he plugged the generator into which made receptacles inside live. Would you just need to put another plug end on the extension cord, so having two plugs on one cord, one plugging into generator and one plugging into outside receptacle on cabin?

Would the wiring have to be set up differently than a normal wiring set up?

If I set up a solar/battery system, could I hard wire the inverter into the existing wiring through a junction box? So I could use the existing receptacles in the cabin to plug in ac loads?

Thanks

Rob_O
# Posted: 5 Dec 2011 21:46
Reply 


Quoting: Klicky1
If I set up a solar/battery system, could I hard wire the inverter into the existing wiring through a junction box? So I could use the existing receptacles in the cabin to plug in ac loads?


Based on your description, I will guess that your plan will work. Is there a breaker panel or is it all just tied together?

Klicky1
Member
# Posted: 5 Dec 2011 21:56
Reply 


No breaker panel. I haven't looked into the wiring too much, just wasn't sure if or how it could work, but since wiring is there and I'm tired of lugging battery back and forth from home, I'd like to get a plan going.

MtnDon
Member
# Posted: 5 Dec 2011 22:03
Reply 


Quoting: Klicky1
There is a receptacle outside that I "assume" he plugged the generator into which made receptacles inside live.


If that exterior rectacle is the standard type that you could plug a tool or lamp into, it is not set up to safely be used to connect a generator to the cabin. That would necessitate a cord between the cabin and the generator with the same male type plug on each end. That could lead to accidentally electrocuting yourself or someone else if the generator was running, the cord plugged into it and you or someone coming into contact with the plug prongs at the other end, the cabin end, of the cord. Don't do that!

There are special female receptacles made for connecting a regular generator cord to the cabin. By regular I mean one male end and one female end on the cord. It may be easiest to obtain one of those from an RV or Marine dealer. RV's and boats use "shore power" cords all the time.

MtnDon
Member
# Posted: 5 Dec 2011 22:09
Reply 


As for solar/battery and an inverter you should have this setup so it is impossible for the generator and the inverter to be supplying power to the cabin system at the same time. There are manual transfer switches made as well as automatic transfer switches. Once again an RV or Marine dealer may be your best source. They are commonly used in RV's and boats.

Note that the RV and Marine type of automatic transfer switches most likely will not be certified or approved under NEC rules, so would not pass a building inspection. However for off grid cabin use I've used them myself and been comfortable doing it. They're usually cheaper than a transfer switch meant for home use with a generator as backup power.

Klicky1
Member
# Posted: 5 Dec 2011 23:21
Reply 


Thanks MtnDon, I only use the generator for power tools, etc... I will not connect it to the cabin. Was just trying to understand why the owner wired things with no power and again, assumed he set it up somehow to be used with the generator, but didn't understand how. For my own understanding though, how does the rv/marine cord your talking about work? Male end into generator and then how does other end connect to cabin?

As for the inverter project, my main hope would be to be able to connect the inverter to the cabin wiring as to have multiple outlets instead of just one coming off the inverter as I have now.

How would you suggest connecting that from inverter to wiring?

MtnDon
Member
# Posted: 5 Dec 2011 23:46 - Edited by: MtnDon
Reply 


The RV/Marine connector is a male plug that is in a recessed receptacle. Sometimes there is a notch for the cord to permit closing the lid while connected

Like this...



They often use a twist lock plug connection.

For connecting the inverter to the cabin, some inverters are made with a set of 120 VAC terminals for hard wiring. I have one like that as my backup inverter.

Is the inverter you have equipped with a circuit breaker on the AC outputs? As long as the inverter was the sole source of power for the cabin I suppose it would be okay to use a cord from the cabin to plug into the inverter output. That idea does make me nervous as it is just "wrong". But it could work. ..... If the inverter is out of warranty and if you are capable, the case could be opened and then hard wired. ...... Hope that helps...

Klicky1
Member
# Posted: 6 Dec 2011 02:51
Reply 


The inverter does not have circuit breaker. It's a smaller, 400 watt maybe. Explain the "wrongness", this is just a bit new to me and I want to know what safe options may be. I'm picturing the inverter coming off solar panel/charge controller/battery and instead of having a power strip for multiple receptacles, it would be hard wired to run power to all existing outlets. Does the inverter have to be wired from inside of it vs. a plug into one receptacle and the other end of it hard wired to cabin wiring? When I am not there I would just shut the inverter off. Assuming they used Romex in the cabin, would I have to have the same gage wire coming off inverter, thus needing to open it up for hard wiring vs. the plug idea?

Thanks

thanks

razmichael
Member
# Posted: 6 Dec 2011 10:03
Reply 


Klicky1, you have not mentioned how much power you want (what will you be running), what battery capacity you have nor anything about a budget. All these things may impact how to handle this project. What you are after is really very similar to how I have my trailer set up (waiting to build the cabin in the spring and migrate the equipment over). Already mentioned above is the danger of not using a proper generator to wiring receptacle as well as the concerns about opening up an inverter (but as mentioned it could be done). If on the other hand you have a bit of a budget, you could invest in a better inverter that includes an autoswitch, smart battery charger, hard wiring option etc. This could be connected to the generator receptacle in case you need to provide power to the cabin (low batteries) or to charge the batteries. The inverter is also connected to your batteries (heavy gauge wiring!). Your solar panels can be connected through a solar charge controller directly to the batteries. I'm making many assumptions about how the cabin is wired (properly) and what you want to do. If you want to see some more details on my set up then there are some photos and diagrams here Photos in the Viking Wiring section. This does not include my solar components (I should update it) and looks far more complex than yours would be because I was incorporating (and bypassing) the trailer converter (thing that converts 120AC to 12DC and distributes both 12v and 120V). Essential however I used the existing distribution components (both 12V and AC) and integrated the inverter and batteries into it. The outside receptacle can connect to a generator or other power source if needed. This setup provided 4 or 5 days of use (including my wife using a hairdryer on occasion) without any concern for the batteries before I added the solar. With the 90 watt panels, I have no problems.

One last point - you really need to do a power budget to be sure your inverter, battery and solar system can handle what you need. Do not forget to account for the inverter loss (around 15% for most inverters).

Rob_O
# Posted: 6 Dec 2011 20:32
Reply 


Quoting: Klicky1
Explain the "wrongness", this is just a bit new to me


They call them "suicide cords" for a reason. Just get one of these and use it to replace that outside outlet


If the wiring is all tied together like you suspect (check it) you can run a standard extension cord from the inverter to the male receptacle and have power at your outlets inside the cabin. Any old extension cord that fits will do

Your 400W inverter isn't going to make enough power to require overcurrent protection, but if you want to use a bigger inverter or a generator you should add some sort of breaker or fuse to the circuit. 15A for #14 wire, 20A for #12

I'd also recommend adding a ground rod, but don't bond it to the neutral. My inverter hated me when I did that!

Good luck with it, if you have any more questions I will do my best to help

VC_fan
Member
# Posted: 28 Dec 2011 08:01
Reply 


I'm not an electrical engineer but it sounds like your cabin is set up about like I set mine up - cheap and quick. And safe as long as we're talking about a few hundred watts. Just do the "Jesus" cord or "suicide" cord by cutting the female end off of an extension cord and replacing it with a male end. Then backfeed your outlets by plugging the small inverter into any convenient outlet (NEVER try this if you're on the grid.) If you want to get fancier you can hide the inverter some place and put a switch in the 12V line to the battery to turn the ac power on and off. As long as the inverter is out of the circuit, you could then also backfeed all the internal outlets with the generator by using the outside receptacle. I had the same issue someone else reported with the inverter not liking it when the neutral and ground were both connected; my outlets are all ungrounded. I'm using a cheap 200 W iBlack & Decker nverter from WalMart that has the wonderful feature of shutting off if there's anything wrong with the wiring - it is the circuit breaker. Again, I'm only reporting what I did and what works. It's not as safe as the systems others will describe but to run a few compact fluourescent bulbs and a radio it works just fine.

sjasperson
Member
# Posted: 16 Feb 2012 17:58 - Edited by: sjasperson
Reply 


Hello,

I am a newbie member and was very, very excited to come across this great small cabin forum. I am in the final planning stages for construction of a 20" x 30' , off grid cabin in Bayfield County, Wisconsin. This will be a walk in cabin approximately 300 feet off the main road. I will be using an outdoor privy, carry in drinking water, and use creek water/rainwater for general purposes. I am still in a daze after all of the special use permits and zoning requirements I had to meet just to build a simple, one room cabin !! I plan to use solar power-deep cycle battery (DC) for cabin lighting which has works out great on a small sailboat i own. I have a general questions regarding the proper and safe hook-up of a 4500 watt gas generator I will be using to power my tools for cabin construction (I feel it would be short sighted in the long run not to build this aternative capability into the cabin design even though I don't plan to use it much....and then probably only for lighting and maybe the running of small appliances ....like a coffee maker, etc). Can someone provide me with a good source of information (diagrams, etc.) that covers the proper hookup? I'm also wondering if anyone knows if it requires a licensed electrcian to do this work (I imagine it varies from state to state)?

Sorry if this is recovering what you have already discussed....but I kind of got lost in all of the replies so far........and most of them did not fit my particular situation.

I'm looking forward to looking over all of the past forum topics and am really excited to find such an active forum involving people who like to keep it simple.

Scott

Rob_O
# Posted: 16 Feb 2012 18:44
Reply 


Quoting: sjasperson
I'm also wondering if anyone knows if it requires a licensed electrician to do this work (I imagine it varies from state to state)?


In my state anyone can sign a form that they are doing their own electrical and get a permit. If you are getting a permit, your electrical has to meet code requirements. End of story. If you will not be grid connected, you probably don't have to get a permit. Call the courthouse and find out for sure.

Quoting: sjasperson
Sorry if this is recovering what you have already discussed....but I kind of got lost in all of the replies so far........and most of them did not fit my particular situation.


When you have figured out what legal requirements you will have to meet, start a new thread with the particulars and we'll be happy to help you through your particular set of circumstances

Quoting: sjasperson
I plan to use solar power-deep cycle battery (DC) for cabin lighting which has works out great on a small sailboat i own.


As a general rule, I discourage people from mixing 12V and 120V in their cabins. When you add up the cost of the extra wiring, special fixtures, bulbs, boxes and all the rest it's generally cheaper to buy another battery and a bigger solar panel. YMMV, of course

MtnDon
Member
# Posted: 16 Feb 2012 21:57
Reply 


For all but the most very basic systems I discourage DC for lights/appliances... especially as frequently systems seem to have more and more demands placed on them. Think it through carefully.

justincasei812
Member
# Posted: 17 Feb 2012 16:09
Reply 


I plan on putting in a load center/ servcie panel in my cabin in the next few days and will hard wire a generator to that for power. My question is how easy would it be to add solar/ batteries after the fact? I would like the batteries to run a few electrical plugs for lighting and a TV if possible without all plugs being hot. If they all have to be hot not a big deal, I just don't want teh kids to turn on lights then not turn them off and drain the batteries.

MtnDon
Member
# Posted: 17 Feb 2012 17:49
Reply 


Quoting: justincasei812
would like the batteries to run a few electrical plugs



What exactly does that mean? AC power from an inverter fed from the batteries, or DC power direct to the receptacles??


Notes:
AC and DC should never be mixed in the same service pane.

If AC sources are both a generator and an inverter there must be a transfer switch to prevent both supplying power to the same places at the same time.

You could have some circuits supplied only by the generator, but those should be in their own service panel.

justincasei812
Member
# Posted: 17 Feb 2012 18:21 - Edited by: justincasei812
Reply 


MtnDon

Honestly I am not sure sort of speak..... I have an off the grid cabin that was wired then left with no plugs or switches and no service panel when I bought it. My thought was to finish the wiring with a panel. I already put in the lights, plugs and light switches. Have the service panel and will be installing it in a couple of days. What I also wanted to do is tie in solar/ batteries into the exsisting wiring if at all possible. This way I am not using a generator all the time for simple things. Nothing major with the tie in like I said a TV and a couple of lights if at all possible. Just not sure exactly how to tie it in with out blowing something up. I know that an inverter and a transfer switch will be needed but like I said still fuzzy with seperating and making it work with the existing wiring.

Rob_O
# Posted: 17 Feb 2012 18:56
Reply 


Justin, what you want to do is possible without using 2 panels

The panel has to be wired so one leg (L2) of the service panel is connected directly to the generator and feeds the other leg (L1) of the service panel through the automatic transfer switch.

When the generator goes online L2 goes hot and the switch automatically disconnects the inverter and all the outlets are hot. Shut down the generator, L2 goes dead, the transfer switch connected to L1 goes back to inverter power and only half the panel has power

justincasei812
Member
# Posted: 17 Feb 2012 19:11
Reply 


Rob_O

I see what you are saying!! I seen something like this jimmy rigged on you tube and knew it wasn't "right" but got the gist of it. Thank you for the response. I now know I need a little bigger panel in which is good since I haven't put the other one in.

MtnDon
Member
# Posted: 17 Feb 2012 20:03
Reply 


Okay, so all the power in the cabin is going to be AC. That was not clear to me, maybe I didn't read far enough back in the thread and my memory fails at times when confronted with the vast array of topics and questions.

So maybe this will help. We'll look at components rather than the whole enchilada.

First the service panel. Wire all the branch circuits from there using breakers. The input to the service panel will come from the transfer switch output, and the transfer switch only. A transfer switch will have one output and two inputs. Transfer switches will switch both the hot and the neutral AC wires simultaneously.

Let's make input one coming from the generator. Then input two will be from the inverter. The switch makes it simple to switch from one to the other. There are inexpensive transfer switches available that can switch up to 30 amps automatically, as soon as the generator is started. Start the generator and the generator is automatically switched to supply power to the service panel as the inverter is automatically switched out.

So then the inverter has its output going to the transfer switch and has the DC side connected to the batteries.

FYI a switch rated for AC service will burn out quickly when used with DC power.

justincasei812
Member
# Posted: 17 Feb 2012 22:06
Reply 


First of all if I diverted this thread I apologize. I know there is a wealth of knowledge on this site and hoped that my question could be of use to others as well. Thank you MtnDon and Rob_O This really pin pointed what I had tried to ask another time and really did not know how to explain it.

MtnDon How fast is "quickly" on the inverter. If it does go out is there any issues to the system/ set up I might have other than replacing it?

Thanks again!!

Kevin

MtnDon
Member
# Posted: 17 Feb 2012 22:40
Reply 


how quickly will depend on the load. I can't put a time frame on it or how many cycles. One issue though is you never know if the contacts will weld together in closed position or burn off in an open position.

There are DC rated wall type switches made, but hard to find and expensive. Probably better to obtain a good heavy duty DC rated snap toggle switch and use that. Carling Switch makes some nice ones in a variety of styles. You may have to use pigtails in the outlet box to connect to the solid wiring. Use a blank switch plate and carefully drill a hole to suit the switch. There are plates with a small hole on the center and some are available in nylon which won;t crack/split as readily as a cheap plastic plate. Make sure the switch is rated for both the DC volts and DC amps being used.

Rob_O
# Posted: 17 Feb 2012 22:56
Reply 


Quoting: justincasei812
MtnDon How fast is "quickly" on the inverter. If it does go out is there any issues to the system/ set up I might have other than replacing it?


Don is talking about using standard hardware store light switches for DC circuits. They die quickly, for a number of reasons

Not too long ago there was a thread relating to inverters, generators, transfer switches and bonding issues. Find it and you will find some additional info you need to know to plan your system

Trapper
Member
# Posted: 17 Mar 2013 10:54
Reply 


Is there not a way you can feed a panel box with the same inlet. Have only one inlet to feed the panel box but have one connector from the generator and one from the inverter with the same connection plugs. This would act as a transfer switch and only one could be plugged in at a time.
You could then have a receptical near your battery set up and charge them when the generator is on. I know there are some precautions to doing this but couldn't this work?

bukhntr
Member
# Posted: 23 Mar 2013 23:59
Reply 


Quoting: Klicky1
How would you suggest connecting that from inverter to wiring?

i just completed my wiring at our off grid cabin today using an inverter. to get all the circuits to the inverter as one line I brought them all to junction box and spliced them to a "source" wire coming from an outlet box near my inverter/battery bank. I used a simple 15 amp plug connected to the source wire 12-2 romex to connect to the inverter. this is new construction so may be different for you but hopefully your wires have an origination point you can join at.

Trapper
Member
# Posted: 24 Mar 2013 10:26
Reply 


I have uploaded a diagram of my plan. I am not sure if the inverter can be wired with this type of outlet plug.
With this method it is impossible to have both connected at the same time and I can wire my cabin with two breakers. One for light loads with the inverter and when using the generator both can be on.
There may be several reasons this may not be efficient and am looking foreward to all comments.
Thanks
wiring diagram
wiring diagram


gcrank1
Member
# Posted: 30 Apr 2021 23:14 - Edited by: gcrank1
Reply 


Another zombie thread, but good discussion.
Ive been running my cabin just as Trapper shows for some time. No mixed 12vdc/120ac, it is ALL 120vac. The diagram is about as simple a Transfer switch as possible, all manual, only one input at a time, gen OR inverter from battery bank/solar, wind or your own hydro (NOT pwr co hydro!)
I usually have the solar system 120vac inverter plugged in via a 12ga. contractor grade ext cord.
The inv/gen runs tools outside or, when the inv. cord is unplugged and gen cord plugged in we can run the microwave, coffee maker, high-draw stuff inside for short periods as needed. Get done, swap the plugs and back to solar. Someday I may get a simple transfer switch to throw, I have to go out to start the gen anyway, no automated switching here!
It is is quick, clean, safe and simple. Pretty much the same thing as plugging in an RV except your solar or gen are 'the grid'.

Brettny
Member
# Posted: 1 May 2021 05:49
Reply 


They do make inverters with automatic transfer switches built in. It will run powert through the inverter if the generator is running or when it's off supply 120v from the batteries. I have never used it but I could see how it would be handy with a remote start generator.

mj1angier
Member
# Posted: 1 May 2021 09:10
Reply 


Quoting: Brettny
They do make inverters with automatic transfer switches built in. It will run power through the inverter if the generator is running or when it's off supply 120v from the batteries. I have never used it but I could see how it would be handy with a remote start generator.


That is what we have. When genny is running it powers cabin and charges batteries. Solar is also hooked to batteries. When genny is off, batteries power the cabin. You really don't know it is switching other than a click and a beep (which can be disabled)

Brettny
Member
# Posted: 1 May 2021 10:56
Reply 


I believe your talking about an inverter/charger. Those are prety seamless and when hooked to an electric start generator prety darn hands off. Unfortunately ours is just a generator passthrough so no charger. The only reason I run a generator at the moment is to charge the batteries. I use a 800w generator and a 30a charger for that.

Your reply
Bold Style  Italic Style  Underlined Style  Thumbnail Image Link  Large Image Link  URL Link           :) ;) :-( :confused: More smilies...

» Username  » Password 
Only registered users can post here. Please enter your login/password details before posting a message, or register here first.