Off Grid Cabin Wiring with my Xantrex TR2412

Timinator
Timinator Solar Expert Posts: 32
Been lurking for a while and finally decided to join. Of course I have a question too. I've had a 12x32 off-grid hunting shed/cabin built and it's being "rough" wired with 2 AC circuits. One circuit has 2 outlets the other 3. I have a Xantrex TR2412 Inverter/Charger that will be supplying the cabin with power. It will be fed mostly from two Trojan T-105's and from time to time a Honda 3000 Inverter generator. The batteries will be charged with both a wind generator I built years ago for dry camping in Mexico and a solar panel. My electrical needs will be minimal while there hunting.

My question is regarding the wiring of the inverter to the "rough" wires coming out of the wall inside the cabin and proper grounding. Do I need to put a grounding rod into the ground and wire/ground it into a simple distribution panel with two breakers for the inside cabin wiring or can I just wire both "rough" circuits directly to the inverter with a plug? The inverter is for "off-grid" applications so I "believe" it's OK to wire it directly but I'm not sure.

Also, do I need to worry about grounding the wind generator tower or the Honda generator and if so where?

Thanks, Tim
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Comments

  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    Timinator wrote: »
    My question is regarding the wiring of the inverter to the "rough" wires coming out of the wall inside the cabin and proper grounding. Do I need to put a grounding rod into the ground and wire/ground it into a simple distribution panel with two breakers for the inside cabin wiring or can I just wire both "rough" circuits directly to the inverter with a plug? The inverter is for "off-grid" applications so I "believe" it's OK to wire it directly but I'm not sure.

    Also, do I need to worry about grounding the wind generator tower or the Honda generator and if so where?

    All of the above need to be solidly grounded for lightning protection and arguably for electrical safety. But the safety ground is mandatory for almost everything in the US, even off grid.

    But what you have to ground to what, via what kind and size of wires, and how the grounds must be interconnected is too large a subject for me to cover here. Read the posts on the subject and then come back with questions and we will be happy to chime in. Recognize that for an authoritative answer you need to ask an electrician with off-grid experience, an EE or a PE.

    Since your inverter will be able to produce serious power, particularly with the generator behind it, the "rough" wiring may need some attention too.
    SMA SB 3000, old BP panels.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    Inquiring mind want to know why on earth you need such a large inverter (2.4kw) for such a small building? Your t105s are not going to deliver anywhere near tht much power for very long, if at all. I suggest, a Morningstar Suresine 300 inverter. With the exception of Pharos a fridge, and a water pump, the Shursine will power everything in such a small house IMHO.

    The buy a good Iota charger to supplement charging.

    The Xantrex is MSW, and will cost y ~$650, the Shursine, pure sine wave ~$300, and a 45 amp Iota will cost ~$150. Not to mention that the Suresine is extremely efficient.

    Tony
  • Timinator
    Timinator Solar Expert Posts: 32
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    I got the larger inverter because there will be times when I'd like more power for short bursts. I've lived for weeks on two Trojans and my wind generator and solar panel.

    The "rough" wiring is what the builders call the wiring when it's not connected to a main panel or one isn't installed. Everything is code wire wise inside the walls and ceiling.

    So everything needs to be grounded. I'll do the searches and read up on what needs to be done......I'll be back!
  • simagic
    simagic Solar Expert Posts: 100 ✭✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    icarus wrote: »
    Inquiring mind want to know why on earth you need such a large inverter (2.4kw) for such a small building? Your t105s are not going to deliver anywhere near tht much power for very long, if at all. I suggest, a Morningstar Suresine 300 inverter. With the exception of Pharos a fridge, and a water pump, the Shursine will power everything in such a small house IMHO.

    The buy a good Iota charger to supplement charging.

    The Xantrex is MSW, and will cost y ~$650, the Shursine, pure sine wave ~$300, and a 45 amp Iota will cost ~$150. Not to mention that the Suresine is extremely efficient.

    Tony
    My question is not to insult, but rather to see if there is something that I don't understand. That appears to be an expensive "MODIFIED" sine wave, when a PURE sign wave can be purchased for less money. MY research on this site has indicated that pure is better. Is there something I'm not getting
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    Sounds like a moot point since he says he already has the TR2412. All he needs is maybe a small sub-panel with 3-4 breakers and he good to go. Feed the box from the Inverter with a back-feed on one breaker ( lift the bond if it has one, green screw ). Read the Manual, but I think you'll have to create a Neutral to Ground bond at the Inverter with a grounding rod , as the Honda does not have one. To feed the inverter from the Honda, you'll need a 30-40 amp plug to the input. I guess your Solar / Wind will go to the batteries. I'd put in a separate lightening ground rod for them.

    If you don't have that Inverter yet, post back.
    .
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    Sounds like a moot point since he says he already has the TR2412. All he needs is maybe a small sub-panel with 3-4 breakers and he good to go. Feed the box from the Inverter with a back-feed on one breaker ( lift the bond if it has one, green screw ). Read the Manual, but I think you'll have to create a Neutral to Ground bond at the Inverter with a grounding rod , as the Honda does not have one. To feed the inverter from the Honda, you'll need a 30-40 amp plug to the input. I guess your Solar / Wind will go to the batteries. I'd put in a separate lightening ground rod for them.

    If you don't have that Inverter yet, post back.
    .

    Bad idea with an MSW inverter. Too easy to get things confused and fry the inverter by having connected to the N-G AC. Leave the AC Neutral floating all the time. It's easier and does not create any significant hazard. The Hondas do not have a metal housing to get energized so there's almost no danger of being zapped.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    Bad idea with an MSW inverter. Too easy to get things confused and fry the inverter by having connected to the N-G AC. Leave the AC Neutral floating all the time. It's easier and does not create any significant hazard. The Hondas do not have a metal housing to ge and it'a lot easierergized so there's almost no danger of being zapped.
    That can get you killed at the kitchen sink for sure, but you know it won't be me and it's easier let'er float. Ever wonder why Mobil inverters have a automatic ground bond ?? I guess I install to many in Boats like that a cabin must be different.
    .
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    Got to do it right.

    Of course "right" in my definition is forget the MSW inverter in the first place, but it's too late for that.

    On the other hand bonding the Neutral to Ground on one is an almost certain way to ensure you suddenly need a new inverter. Then you buy the sine wave unit and set up the grounding properly. Problem solved.
  • Timinator
    Timinator Solar Expert Posts: 32
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    There is no "pluming" in the house. Only thing metal is the roof, the two wiring circuits and the wood burner and chimney. There will be a kitchen sink though. Water will be supplied from a large jug by a 12v on demand pump (RV type) with a small 12v battery. Water drain will be into a 5 gallon bucket under the sink. No wall plumbing though.

    I got the Xantrex TR2412 because it was the one that Xantrex phone support recommended to me for this application. I tried to ask the required grounding questions to them and was given very vague answers; "some do it this way, some do it that way....". No help really. I can understand that from a liability stand point.


    So, if I were to do it the "right" way, what inverter would you recommend and how does that help with the grounding. I'm not apposed to bailing on this inverter and doing it right the first time. I thought I was with this "off grid" inverter, but maybe I jumped too soon.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    Anybody see a Neutral to ground here ?? If I am wrong, I'll take the hit.

    Attachment not found.


    http://lib.store.yahoo.net/lib/wind-sun/Trace-installmanual.pdf
    .
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    The unfortunate truth is that there are many differing opinions on proper grounding. It does absolutely nothing most of the time; it's there in case something goes wrong.

    Some of us lived for decades in houses that had no grounding at all. No one got shocked much less died as a result.

    Technically with a floating Neutral system you would have all the ground connections to Earth ground and the neutral line protected by breaker ganged to the hot (as both are actually hot). The only difference is the lack of N-G bond that pulls Neutral to zero Voltage potential in respect to ground. This is what you can't do with most MSW inverters. Check the manual on yours for specific grounding instructions.
  • Timinator
    Timinator Solar Expert Posts: 32
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    Anybody see a Neutral to ground here ?? If I am wrong, I'll take the hit.

    Attachment not found.


    http://lib.store.yahoo.net/lib/wind-sun/Trace-installmanual.pdf
    .


    In this diagram they are using a generator disconnect. I was just going to wire a plug into the AC "In" of the Inverter and plug in the generator when needed. Should I put in this generator disconnect because of the grounding needed?
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    Timinator wrote: »
    In this diagram they are using a generator disconnect. I was just going to wire a plug into the AC "In" of the Inverter and plug in the generator when needed. Should I put in this generator disconnect because of the grounding needed?
    It's fine to just plug direct so you can un-plug it when your gone or starting the generator, personally, I like a disconnect and hook the cord to it with one breaker and plugin.

    If you ground it, it has to be at one place. Since " this " Inverter has straight through neutral & ground and the Inverter is a power source, my understanding is that is were you you want the neutral - ground bond. I may be wrong but their drawing also shows this. There are a heck of a lot posters with more expertise in this then me. I have installed 4-5 if these in a Mobil type system's and I grounded them that way.
  • Timinator
    Timinator Solar Expert Posts: 32
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    It's fine to just plug direct so you can un-plug it when your gone or starting the generator, personally, I like a disconnect and hook the cord to it with one breaker and plugin.

    If you ground it, it has to be at one place. Since " this " Inverter has straight through neutral & ground and the Inverter is a power source, my understanding is that is were you you want the neutral - ground bond. I may be wrong but their drawing also shows this. There are a heck of a lot posters with more expertise in this then me. I have installed 4-5 if these in a Mobil type system's and I grounded them that way.

    OK, so with respect with the diagram, I can bypass the generator disconnect and wire all three wires of the generator directly to the AC IN of the inverter. Then, using an AC Distribution Panel like the diagram, just Ground the Ground and Ground the Neutral like the diagram?
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    Yes you can, but remember as soon as you cut the generator the Inverter then becomes a power source once the transfer is made. When the generator is supplying power the Transfer Switch is bypassing it's power to loads and just using power for the charger.

    What Coot was talking about, is true about MWS inverters, this Inverter is really a On-Grid being used off-grid.

    In that Diagram they are making the bond on the ground buss. I generally do it back at the Inverter, no biggie. If you have grid power it would be done different.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    Anybody see a Neutral to ground here ?? If I am wrong, I'll take the hit.

    http://lib.store.yahoo.net/lib/wind-sun/Trace-installmanual.pdf
    .

    Yes, there definitely is an N-G bond in that diagram.

    That only proves that the TR is one MSW inverter that can have it.
    It does not prove that the majority of them can not have it.

    If you don't believe me, try it yourself with a few dozen of them of various brands and models. On your nickle. ;)
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    Yes, there definitely is an N-G bond in that diagram.

    That only proves that the TR is one MSW inverter that can have it.
    It does not prove that the majority of them can not have it.

    If you don't believe me, try it yourself with a few dozen of them of various brands and models. On your nickle. ;)
    You are correct ( and I said that ) on some / most MSW Inverters. " This " one is a ON-Grid Inverter being used Off-Grid. No disagreement here, your my Hero.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    It's a case of always check the instructions for your specific inverter, no matter what the question! :D

    You can find an amazing amount of info in those manuals, and the Internet makes it possible to see most of them before you even buy the thing. People should definitely take advantage of that. ;)
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    My Boats are quite large ( 50-110' ft ) they have every amenity as you have at home and then some. Most Mobile Inverters lack the features and the programming variables that they require. As On-grid Inverters have advanced, Mobile inverters have stayed about the same and are limited on what they offer. The last 4-5 years I have switched to On-grid Inverters. Because of the " Shore Power " and the power on board ( Generator & Inverter ) you have to install them a little different. So you have to put the neutral - ground bond on a relay, to make and break the bond depending on the Power source. This Trace just happens to be one I have used in the past, a OutBack TWS is the same as most of the On-grid, used Off-grid.

    How about this Sub-Panel and this just the AC. It has 3 inverters all sub-paneled within the sub-panel and it still has some room to expand. It has 240v in the center. The breakers at the top switch the Shore power to onboard power / with lock outs.

    Attachment not found.
  • Timinator
    Timinator Solar Expert Posts: 32
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    I was actually looking at a marine power distribution panel like this. None with the ground switching though.

    http://www.bluesea.com/products/8043/Traditional_Metal_Panel_-_AC_Main_%2B_3_Positions%2C_AC_Voltmeter
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    Timinator wrote: »
    I was actually looking at a marine power distribution panel like this. None with the ground switching though.

    http://www.bluesea.com/products/8043/Traditional_Metal_Panel_-_AC_Main_%2B_3_Positions%2C_AC_Voltmeter
    Yep, that's because they do not have a bond in the Distribution Panel like the one in the drawing, so you create one at the Inverter. Your Honda does not have one either, if you change generators you need to check it. Where you can have a issue is with some light fixtures and hot water heaters with a leaky element. Coot is right, all us old timers never did have grounds and some of us are still kicking. Back in our day things did not care about polarity either.
  • Timinator
    Timinator Solar Expert Posts: 32
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    Yep, that's because they do not have a bond in the Distribution Panel like the one in the drawing, so you create one at the Inverter. Your Honda does not have one either, if you change generators you need to check it. Where you can have a issue is with some light fixtures and hot water heaters with a leaky element. Coot is right, all us old timers never did have grounds and some of us are still kicking. Back in our day things did not care about polarity either.


    OK, since the Inverter want's a neutral to ground bond would it matter if you connected them both to the ground buss on that panel? Isn't that the same thing?
  • Timinator
    Timinator Solar Expert Posts: 32
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    It's a case of always check the instructions for your specific inverter, no matter what the question! :D

    You can find an amazing amount of info in those manuals, and the Internet makes it possible to see most of them before you even buy the thing. People should definitely take advantage of that. ;)

    I agree, that's always the best way, but sometimes I honestly don't understand every damn thing they say! Thank god for you guys. You argue among yourselves for a while then you all seem to come together on a solution. Gotta like it!
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    Timinator wrote: »
    OK, since the Inverter want's a neutral to ground bond would it matter if you connected them both to the ground buss on that panel? Isn't that the same thing?
    No difference as long as you have just one. There was actually a caveat that was not in the screen shot. The reason I do them at the Inverter is because the incoming power to the Inverter is what lifts the bond with the relay when the mini grid shuts down and becomes a part of the overall system.

    Attachment not found.
  • Timinator
    Timinator Solar Expert Posts: 32
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    No difference as long as you have just one. There was actually a caveat that was not in the screen shot. The reason I do them at the Inverter is because the incoming power to the Inverter is what lifts the bond with the relay when the mini grid shuts down and becomes a part of the overall system.

    Attachment not found.

    When you say "do them at the inverter" are you jumping the neutral and ground at the AC input of the inverter or at the AC output, or just grounding the chassis of the Inverter?
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    Timinator wrote: »
    When you say "do them at the inverter" are you jumping the neutral and ground at the AC input of the inverter or at the AC output, or just grounding the chassis of the Inverter?
    I do them on the output of the inverter, the input is what powers them, as they are normally closed ( N/C , creating the bond). If they were done at the panel you'd have to go to each panel to un-bond them. Since you only have one, you don't care. A mobile inverter does it automatically with the transfer switch. You just need to do it somewhere. They will end up at the chassis ground and that goes to a ground rod.

    Added : I don't know if you noticed, but the panel you posted has a double throw breaker input 120 V. It's setup so it breaks the hot & neutral if it trips. If you neutral bond from it you need to do it on the line side of the breaker. You really don't need that kind of a breaker there anyway. Those panels are very modular, you can remove the double handle / double throw and replace it with 2 singles. If you have 2 inputs you can remove 2 of the other ones and install another double throw and have 2 input sources with different neutrals and a lock out slide.
    .
  • Timinator
    Timinator Solar Expert Posts: 32
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    I was going to go with a pair of Trojan T-105's but I found these Power Sonic AGM PG-6V210-FR's NIB for $200/ea, no tax, no shipping. Seems like a good battery, am I missing something or should I jump on these?

    http://www.mouser.com/ds/2/331/PG-6V210_11_Jan_12-19511.pdf

    I'll only be staying at the cabin for a couple days at a time and I'll have my solar panel and wind generator to help keep them up while there.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    They appear they may be GEL type batteries... A C/10 maximum charge rate--So make sure you do not exceed that with your solar+wind charging sources.

    GEL/Sealed/AGM batteries typically do not like "over charging"--And shunt controllers (used for typical wind turbine setups) are not as "friendly" to keeping float voltage stable. Flooded cell batteries just require you to add a bit more distilled water if they are over charged somewhat.

    Personally, I am not a big believer in small wind, so I would tend to ignore the wind turbine and just design the system around the solar.

    If your wind turbine does perform well, I would suggest using flooded cell batteries instead. And/or setup your wind turbine so you can shut it down (switch to short circuit the turbine output, furling, etc.) when you are not there (especially during the windy times of year)--at least until you have seen how everything plays together during high winds. You probably do not need the wind when you are not there anyway (the sealed battery can go 6 months without charging if fully charged before storage--and no loads). In any case, the solar should be enough to float the batteries without wind when you are not there.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Off Grid Cabin Wiring with my Xantrex TR2412

    If you've never had a system before, don't buy any type of sealed battery to start with unless it is absolutely necessary. It's much easier to keep an eye on flooded cells and they are more forgiving of mistakes.

    Something that needs to be clarified about the N-G bond:
    Blackcherry04 speak of 'lifting' it when shore power is supplied. This applies where the external AC power is from 'shore', as in a marine or RV dock hook-up which will already have an N-G bond at the supply. In that instance you do not want a redundant bond within your system.

    For a stand-alone application such as a cabin there would be only one N-G bond, usually in the AC distribution box, and it does not need to be 'lifted' ever as the generator would not have one.
  • Timinator
    Timinator Solar Expert Posts: 32
    Re: Off Grid Cabin Wiring with my Xantrex TR2412
    BB. wrote: »
    They appear they may be GEL type batteries... A C/10 maximum charge rate--So make sure you do not exceed that with your solar+wind charging sources.

    GEL/Sealed/AGM batteries typically do not like "over charging"--And shunt controllers (used for typical wind turbine setups) are not as "friendly" to keeping float voltage stable. Flooded cell batteries just require you to add a bit more distilled water if they are over charged somewhat.

    Personally, I am not a big believer in small wind, so I would tend to ignore the wind turbine and just design the system around the solar.

    If your wind turbine does perform well, I would suggest using flooded cell batteries instead. And/or setup your wind turbine so you can shut it down (switch to short circuit the turbine output, furling, etc.) when you are not there (especially during the windy times of year)--at least until you have seen how everything plays together during high winds. You probably do not need the wind when you are not there anyway (the sealed battery can go 6 months without charging if fully charged before storage--and no loads). In any case, the solar should be enough to float the batteries without wind when you are not there.

    -Bill


    Actually, when I'm not there, the batteries, wind generator, panel and inverter won't be there either. Too "depressed" of an area to leave this stuff at.

    I understand about "small wind" but this isn't a permanent system. When I get there I'll have the fully charged batteries with me. I'll just have to "survive" for a few days. Good point about the wind controller shunts. I didn't know about, or think of that. I guess I have to make sure I have one with an adjustable set level to go to dump.

    The wind generator was something I built from scratch in the late 80's so it goes where my solar goes. I used an old computer tape drive motor and an ultralight prop then fabricated everything else myself.

    Getting back to the batteries, would you still go for flooded? I guess another reason I was thinking of these was that I could safely use them inside the cabin which would save me another hole in the cabin.