Grounding my inverter

[xyxoxy]

Well I'm finally close to setting up my little off-grid solar experiment to put some lights in an out building. I have just about everything I need and I've been reading like crazy for weeks to be sure I have a good plan.

I was originally planning to run a 12v DC only system but then decided I would prefer to add an inverter to have the option of using either DC or AC powered lights. I believe I have everything covered including breakers, fuses, proper charge controller, battery protection, etc. One of the last pieces of the puzzle is how to ground my inverter. I'm using 8 foot copper coated ground rods and #6 wire with the proper clamps etc for the solar panels and for the negative side of the DC power system. I have a ground bus so that I can connect everything at one point.

My question is whether I can connect the inverter's ground terminal to that same ground or if it has to be separate. I have read numerous posts and other references and have seen just about every possible answer. "You MUST use the same ground." "You must NOT use the same ground". "It's a waste of time to ground it at all".

The inverter I chose is a Power Bright PW1100-12 which is an inexpensive MSW inverter I found on Amazon. Unfortunately the manual is no help as it tells me to "Connect a #8 gauge stranded insulated wire to the ground terminal and connect the free end to the vehicle chassis or any other ground point". Perhaps I can't/shouldn't use this inverter in an off-grid solar application?

If you have any thoughts about whether I need a different inverter or the best way to ground this one I'd appreciate it and I would also appreciate some explanation or the reasoning behind your answer.

Thanks
-Mickey

[Sunking]

My question is whether I can connect the inverter's ground terminal to that same ground or if it has to be separate. I have read numerous posts and other references and have seen just about every possible answer. "You MUST use the same ground." "You must NOT use the same ground". "It's a waste of time to ground it at all".

Grounding is a complicated subject for laymen and honestly even for some electricians.

Ok if you have a ground electrode system for the facility all system grounds have to use a common earth ground. They cannot be separate as doing so would put you at great risk. NEC 250 is very clear on this subject.

You need to read and understand this document if not then you should not be doing this as DIY

[xyxoxy]

I have seen that document and have been trying to digest it. It's pretty comprehensive and there is a lot of info in there that doesn't really apply to my situation.

I don't actually believe I need to understand every possible install variation to complete my project, especially since this is mostly intended as a learning experience and I am doing everything possible to proceed with caution and good information. But I would agree this type of project isn't for the average weekend warrior who expects to make a trip to Home Depot and be off the grid by sunset.

I also know enough not to trust a "professional" without knowing something about the project myself. So if/when I do one day hire someone to install a larger system I'd like to be able to have an intelligent conversation with them and know if they are full of BS or not. Anyway that's kinda what's behind this project and I appreciate the words of caution.

As for grounding, what you suggest is precisely what I was planning until I read a couple of posts from people who claim to have fried their inverters by grounding them to the same point as their DC neutral. I'm aware of the potential hazard (no pun intended) of having two ground rods in close proximity but I also don't want to fry my inverter.

I have read that the difference may be between using a PSW inverter as opposed to a MSW. But if I can use the MSW I already paid for I'd prefer to do so.

[Mike90250]

Only ground the mod sine inverter from it's provided ground terminal, read the manual to find out if the battery - should be connected to ground too.

[xyxoxy]

Yeah the manual is just a little better than useless and doesn't mention anything about grounding the battery one way or another. It basically just takes several pages to say "Connect all the cables and don't do anything stupid".

I kinda used this Jeff Yago article as a basic guide. Here the negative terminal is grounded, though he stops short of adding an inverter.

[Sunking]

The problem you are running into with your inverter is it is not designed or intended to be used in a premises wiring system.

This will confuse the crap out of you but if your system is a 12 volt battery system, it is not required to be a grounded system, but the frame work is always required to be bonded.

All this means is the current carrying conductors of the 12 volt system, the positive and negative conductors are not required to be grounded. However if you do not ground them none of your fuses or breakers are going to work, and other means has to be provided to protection of the the conductors from over current. The only way for a fuse or breaker to operate is for it to have a planned return fault path back to the source.

[xyxoxy]

No that makes perfect sense.
I've never owned an RV or a boat so I need to pay more attention to the context of what I'm reading. I wasn't thinking about that when I bought the inverter... I just looked for something that seemed sturdy and was a good deal. I guess for this project I'm trying to find a balance between setting up something safe and reliable while not breaking the bank.

Anyway, I think I have my answer.
Thanks again!