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Small Cabin Forum / Off-Grid Living / Generator for off grid cabin question??????
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chatycady
Member
# Posted: 19 Oct 2018 17:41
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I am going to use a generator for an off grid cabin. Here is what I want to do.

I want to take a 30 amp generator cord, cut off the female end and back feed in panel to 30 amp breaker. I realize this will only feed one side of the panel. I will bury the cord under ground to cabin from generator. Male end can be plugged/unplugged at generator. See any problems? (Panel and generator will be properly grounded.)

Nate R
Member
# Posted: 19 Oct 2018 19:28
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You can bridge the main lugs to feed 120V to the other side of the panel, too.

No real problem, just attach a cord through a junction box to UF-B cable, rated for underground power transmission.

toyota_mdt_tech
Member
# Posted: 19 Oct 2018 19:40
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chatcady, whaty Nate said. The input lugs on the top of the panel, where your normal service would come in, ie L1 and L2, make a jumper, I'd use black color, but any color other than white or green will work and use heavy enough gauge, ie 30A gen plug, use a min of a 10AWG wire. Jump L1 and L2 inputs at the panel

But a better solution, build you a 30A circuit feeding an inlet (backwards outlet) and dont cut that female end of the cord off. Plug it in. Done.
Grab one of these.
https://www.amazon.com/Power-Twist-Inlet-Stainless-Steel/dp/B01N0GHPUJ

offgrididaho
Member
# Posted: 19 Oct 2018 22:37
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Am planning to use a similar 30a inlet to the one toyota_mdt_tech linked above, was curious if I the inlet needs to be mounted in a junction box or if I'm good just using the wire cover that comes on the back of the inlet?

-- Bass

toyota_mdt_tech
Member
# Posted: 19 Oct 2018 23:33 - Edited by: toyota_mdt_tech
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Idaho off gridder, you will want it in a box. They make those for boxes too.

This one is surface mounted.

You mentioned away from cabin, maybe just bury a post away from cabin, mount this in the remove box mounted to a 4X4 post and with your UF feeder wire, run it underground into your panel to the 30A breaker. Sanitary and away from cabin like you wanted.

https://smile.amazon.com/Reliance-Controls-Corporation-PB30-Generators/dp/B000BQT47S/ ref=sr_1_3?ie=UTF8&qid=1540006246&sr=8-3&keywords=30+amp+generator+inlet+box&dpID=41f FIpOlSIL&preST=_SY300_QL70_&dpSrc=srch
71NQGuHDJL._SX425_..jpg
71NQGuHDJL._SX425_..jpg


cspot
Member
# Posted: 20 Oct 2018 08:29
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I haven't done it yet, but I already bought an inlet to do what Toyota said. This way you can just plug your generator right in.

offgrididaho
Member
# Posted: 20 Oct 2018 19:19
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BTW, what's with the four prong 30a inlet... I thought the standard (coming from the RV and boat world) for 30a twist lock was three prong?

darz5150
Member
# Posted: 20 Oct 2018 20:41
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220 volt.

Cowracer
Member
# Posted: 22 Oct 2018 09:29 - Edited by: Cowracer
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Quoting: offgrididaho
BTW, what's with the four prong 30a inlet... I thought the standard (coming from the RV and boat world) for 30a twist lock was three prong?


30A-110 volt single phase campers are going the way of the dinosaur. A great many (including mine) run a 50A-220 split phase connection. It's been quite some time since I seen a 3-prong 30A connector in a campground

Its so nice being able to run the A/C, coffepot and the microwave at the same time without blowing a breaker.

Tim

offgrididaho
Member
# Posted: 22 Oct 2018 10:53
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Interesting... don't plug our van in much but when we do we always seem to find 30A three prong... if I use a four prong inlet I guess I'd have to wire my own generator "plug" from the 30A 3 prong twist lock on generator.

offgrididaho
Member
# Posted: 4 Nov 2018 20:27
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I now see most 30a "generator" inlets and cords are the L14-30 plug style, 4 prong. With an eu2200i companion I would just use an adapter and everything beyond adapter would be four wire:
https://www.amazon.com/Generator-Adapter-L14-30-Female-Voltage/dp/B07GMVJV7X/ref=asc_ df_B07GMVJV7X

TranquilMan
Member
# Posted: 6 Nov 2018 23:14
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Just curious Chatycady. You say off-grid cabin and generator. How big is the cabin and what kind of loads are you going to have? What size is the generator and does it run on gas, diesel or propane? Are you planning to run it 24/7? Only reason I'm asking is because I've got an off-grid cabin that we use May to October with a long boat ride to get to. We have a propane fridge, stove and freezer and run our water pump, lights, radio, CD player and cell phone booster off a small solar system. The only time I turn on my generator is to use power tools when I'm building something. Nice and quiet that way and we don't need much fuel except propane which is easy and safe to haul in 20, 30 and 50 lb. cylinders. Just wondering.
Tranquil Man

offgrididaho
Member
# Posted: 7 Nov 2018 10:39
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TranquilMan,

Where is your cabin latitude wise? How big is "small solar" to you?

I am hoping to end up where you are now, running generator when I need power tools / shop vac something like that, or in later fall / earlier spring when we won't get much light, but otherwise hoping to run off propane (we have large tanks on site) and solar.

My current calculations for summer use run to about 2,500 watt/hours per day but I think I'm overestimating (no well pump, no water pump, propane fridge and stove) and would like to consider smaller solar for easier mounting (idea of wrestling 4" schedule 40 mounting pipe and concrete bags is daunting).

-- Bass

Nate R
Member
# Posted: 7 Nov 2018 13:30
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Bass,
Do you mind sharing your calcs? Seems high to me. For comparison, I'm looking at about 950 WH/day for 2 people in a similar situation.

TranquilMan
Member
# Posted: 8 Nov 2018 16:13
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I agree that the load estimate above seems high. But then what will you be operating and how big do you want the solar system to be?
Here is my long answer to the short question from chatycady and offgrididaho.
We are on a small island in an unincorporated area of NW Ontario just a few miles north of the Minnesota/Ontario border.
Lat. 49 29 N
Long. 94 43 W
We use the cabin from early May until early October. Most of the time it is just my wife and I but occasionally have 1,2 or 3 visitors at a time. The cabin is 682 sq. ft. and has 2 small decks. It was built back in the 1950's and was abandoned and run-down when we bought the property 25 years ago so for me this has been a passion project in a beautiful setting. The cabin was originally wired for 110 VAC and powered by a 10 KW gas generator shared with a couple of other cabins. We sold the generator and I proceeded to renovate keeping the 110 VAC wiring so I can power the cabin with a small generator if I need to. I started adding solar power several years ago with separate 12 VDC wiring. We now use solar power in the cabin almost 100% of the time. I only use the 110 wiring if we want to use the generator for a high draw appliance such as a vacuum. The cabin doesn't have a washroom. We have an outdoor shower and outhouse. Four years ago I built a separate washhouse out-building (100 sq. ft.) with shower, sink and composting toilet. Lights are off the cabin solar power.

My solar system started small but grew over time as we added stuff. Right now we have a total of 12 lights, a 150 W power inverter and a cell phone booster. The inverter is for a small stereo, satellite radio and charging small devices. I have 100 W of panel power on the roof (simple light aluminum angle frame support) and 2 - 6 VDC Trojan batteries stored in an insulated, vented enclosure outside the cabin. This gives us about 250 Ah of stored power. Everything works great but we do need to be fairly conservative in our use in the fall when daylight hours are shorter. I plan to add 2 additional batteries next season to double our stored power and another panel to quicken recharge time. The availability of affordable LED lighting saved us from having to grow the system a few years ago. LED lighting was a huge advancement for us because of the incredible efficiency. My overall objective was to keep our off-grid cabin living simple, practical, elegant. We have a propane stove, fridge, small freezer, barbecue and on-demand water heater.
A second independent solar panel (30 W) and deep cycle battery is located down at our dock to power dock shed lights and a 12 VDC ShurFlo water pump that supplies lake water to the cabin.
This all works great for us. I have 2 generators. A small Honda 500 will power all our basic cabin needs if the solar fails. It will run for 3 h on 0.8 L of gas. I also have a Honda 2500 for power tools (small 10" table saw, chop saw, shop vac, etc.) I have 3 buried power lines that run from my generator shed to the cabin, the dock and my outdoor work bench. I just plug into whichever line I want when I need it. We don't need much gas and only have to change the oil once at the end of each season.
Our sun orientation is East through South so charging time has been fine.
I plan to build a 10 X 16 out-building next year that will be an Art Studio for my wife. It will have a bed in it so it will actually be an Art/Bunkie. It will have a small solar system of it's own similar to the dock setup just for some lights. One thing that I did that proved to be educational was to measure the actual draw of each and every device and light bulb in order to understand the loads. For example, a CD player draws a lot more than a cassette or radio. We don't have TV and don't leave our cell booster on all the time. Our load controller is 10A so we can overload the system if everything is on resulting in a brownout. We do have to remind visitors to turn off lights when not needed. Also, keep in mind that appliances that produce heat draw more power. We don't have an electric coffeemaker, toaster, microwave or kettle. We use the propane stove for things like that.
My objective was to keep things low key and fairly simple because I didn't want to have to rely on expensive outside help or service calls. Also, everything that goes to our cabin goes in by vehicle and then a boat. And then all the garbage and compost goes back out by boat and then vehicle. We try to live green and simple while enjoying the beauty of nature. Hope that answers your questions and apologies for driving this thread somewhat off topic from Chatycady's original question about generator wiring.
TranquilMan

offgrididaho
Member
# Posted: 9 Nov 2018 18:13
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Thanks for the detailed reply TranquilMan. We are trying to keep it simple as well, and I don't want to overbuild just because I can, but I also don't want to have to build this up a bunch in just a year or two so I'm trying to hit that sweet spot. I also don't want to run the generator any more than absolutely necessary, it's just a pain, I have to haul every ounce of gas to the island by boat, and I like the quiet constancy of solar.

Nate R, I agree my calcs of 2500 seems high but kind of is what it is. I have tried to add things I might want to use in the future (occasional microwave, for example, even though we don't even have one right now), and have also tried to take into account the inefficiencies I'll have with the inverter etc, fact that charger won't ever put out full power etc. That being said, it's more like 2,000 watt/hours in summer and 3,000 watt/hours in shoulder seasons (when I also have potential for multiple days of little or not solar).

Can't seem to figure if I can attach a document so just took screenshots of the summer and winter spreadsheets I created for power draw... these are definitely pessimistic (i.e. I doubt we'll hit this power draw regularly) but wanted to make sure I didn't underestimate.

Summer:
Summer use spreadsheet

Winter:
Winter use spreadsheet

-- Bass

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