Ground terminal on PJ 6000

I am eventually going to upgrade this to a GS one.  Does GS have plans for a modular system, ie separate charger, transfer switch?  

I am doing something weird, 120v in to charger, 220v out on inverter for tools. 

Easy peasy for a GS system with the latest hardware...give it 120v in, it'll provide 240v split-phase output from that.  (Note that you will be limited to 3kw due to the amperage limits.)

No, as the charger function is intrinsic to all of the parts also used for inverter function.  In other words, dual-function parts--they are not physically separate.

Noisy L2 because there's no AC filtration on L2 😉.

Yup.  Center tapped secondary.

Should have a 10nF decoupling cap.  UL basically requires that the grounding be kept centered between the power potential--which decoupling caps do. 

Even so, you should get a reading unless they've just completely not wired chassis ground to anything...

The inverter is never a ground source.  It needs ground, but will never be capable of providing ground.

Only earth is a real ground source.

Cool.  If GS inverters can do 120 in 220 split phase out w a 3000w limit on shore thats totally reasonable, no need for splitting the system with that kind of flexibility.

How is ground a real source when a battery's electrons would never be able to return to that kind of ground?   A ground is supposed to be a return path for inadvertent stray electrons.   In the case of house power, neutral and ground are bonded in the box, and the pole is grounded too.

A battery would also not ground to real earth as the voltage is too low for the earth to be a good conductor.

I guess I am going to leave ground floating on the inverter and bond neutral and outlet ground in the breaker box.   I don't think it would function as a ground unless neutral was also ground tied in. 

Ground as a ground only makes sense for grid systems, or maybe 120v+...hmm

I do get a reading but it quickly falls to 0v between L1 and inverter ground.  I feel like if it was actually tied to earth it would not function at all - a metal trailer would still have a hot skin if l1 or l2 touched it and it was attached to earth along with inverter ground.

The on-inverter outlet ground pin is tied to the chassis and ground bolt on the inverter.

The only way it would remotely function is if inverter neutral had it's own grounding rod into earth as well as inverter ground, outlet ground and outlet neutral bonded in breaker box, and the inverter ground never touches outlet ground.  Any other way would create ground loop issues.

I should NOT bind inverter neutral to inverter ground, with or without grounding rods, I don't think - neutral and ground couldn't share a grounding rod because it would basically bypass that capacitor and I have no idea what impact that would have on the inverter...?

I don't understand why UL would require ground to be in the center of the two potentials either - house power it is normal to see a few volts between neutral and ground if the line is far away, or more if the line is also under load.   The point of ground is for safety - secondary return path for electricity on metal skin appliances.  Some technicality of needing to be at 0v potential shouldn't get on the way of that 😐

If the inverter neutral leg is the path back....the center tap - then that is ground, and it can also be tied to earth... don't just call it ground because it is attached to the ground but non functional as a path back. 

I just am taking issue with the concept of a ground-on-paper only here, which seems like what it is.

If L1 and chassis ground got shorted, it should blow the fuse.  Not sure what would happen with that tiny screw and decoupling cap if I tried to wire it as a ground.   It would probably explode and melt before the fuse blows. 

Input/output will always be either equal or 2x (i.e. 120v in -> 240v out, or 240v in -> 240v out).  This also applies lower, i.e. 110v in -> 220v out.  GS inverters can auto-switch their input between 120v and 240v as needed; output is always 240v split phase.  Or 220v, depending on configuration, setup, etc.

So I'm not by any means an expert on grounding--actually I'm not on very good terms with it...but here's my 2 cents:

Grounding should never be a power source/sink.  Think GFCI outlets...if power happens to end up going through the ground circuit, they trip power off. 

However, when talking about grounding "as an entity", grounding definitely has a source, i.e. "beginning" (the ground rod)--but the inverter or any other "ground consumer" is not the source of grounding.

From a technical standpoint, grounding is intended as a power reference, to reduce the risk of shock by zeroing out differing electrical potentials.  It is only supposed to be "tying together" all metal surfaces to reduce the risk of shock--and is never supposed to be carrying notable power.

With this in mind, grounding is most often a metal ground rod driven into the dirt--simply because back when a lot of grounding rules were implemented, most plumbing was metal--and it went into the ground.  If an isolated electrical potential (transformer or otherwise) was not at least loosely referenced to the same earth potential as said pipes (which for that matter can often be found used as a ground source in homes!), there was a high possibility of getting an electrical shock due to the electrical potential difference when in contact with a water source such as sinks, tubs, etc.  (And it doesn't take much current to be lethal.)  This is why GFCI outlets are often required by code when outlets are installed near sinks, tubs, etc.

Yes, even though pipes these days are often PVC plastic, water generally can conduct electricity--and end up being an earth ground source due to coming from a well or other "dirt-based" source.  (I say "generally" because pure distilled water is not conductive!)

Oh, yes.  I meant there's no need for a modular system if GS is doing that.  As in it is perfect as designed.   Didn't mean split as in split phase.  Meant split\modular system.  I don't see any other inverter chargers on the market doing that so that is amazing.

The output of a GS power inverter is electrically isolated from the DC input.  You could technically ground any of the output terminals as a result.  (Can't quite say that about a PJ...the AC voltage feedback isn't quite 100% isolated.  Over a hundred megohms technically might count, but that's why I say it isn't 100%.)

Again, grounding is intended as a power reference, to reduce unintentional power potential between household items and power.  But this is why I keep stressing that an inverter is not a source of grounding: due to the internal electrical isolation, the inverter itself is not able to provide "an electrical path back" to anywhere.

Yes, power is transferred, and yes, power flows through the inverter and battery.  But the electrical isolation of the transformer means that the AC output could easily be at an electrical potential several thousand volts away from the battery.  And let me tell you, you'll definitely feel that if you touch the DC side and something connected to the AC side at the same time.

If you eventually do, remember that they copied GS 😉.

In house power it is a path back - a bad path.  If you have a metal toaster, the skin is supposed to be grounded.  If line power attaches to skin, it shorts and trips the breaker.  N and G are bonded only in the breaker box. It has to be a path back to function as the safety mechanism.   I am not an expert at all, just scratching my head as I saw posts here with people bonding inverter ground to trailer shell where battery - is also tied to shell - that smokes the inverter.

I wonder then if the system needs like 3 earth rods - inverter ground on it's own, breaker panel neutral and ground bond + ground rod, and battery ground rod.

Since you said the inverter is floating, could be thousands of volts away from the bat, THAT would flow through an earth ground rod totally fine. 

The resistance and capacitance of earth would prevent general issues of power flowing the wrong way with separate rods. 

I know if all these things were tied to a single rod the PJ would start smoking.

I am a bit sussed out by the PJ.  So the GS is using a more expensive isolation transformer?   PJ is designed to throw people across the room I guess.  There's a reason these are $300

Maybe just need to leave ground floating, neutral ground bond the outlets, and never be a conductor between any AC output and bat, or run several separate grounding rods when parked.  Thanks for the insight 😂

Care to reference the post in question?

if you're thinking of the thread by Nilao, I'm still not sure what's going on there. 

Due to the electrical isolation inside GS inverters, I can safely short any AC output/input line (or the case) to either battery positive or negative with zero ill effect.

That's not the point of a grounding system...the point is to get all "touchable" potentials at the same potential, to reduce the risk of shock.

It shouldn't...I've done it with the PJ inverter on my bench.  Electrically, several hundred megohms of resistance isn't going to pass any appreciable current; worst case, it'd kinda mess up the voltage regulation.

Main transformer is wound by the same factory.  Isolation in the main tranny isn't the issue (unless you have a faulty tranny!)--it's the isolation for the voltage feedback that's not quite electrically isolated on a PJ.

Yes, Nilao's post.  Do you think it is "proper" to bind inverter ground to inverter neutral to battery neg to trailer skin to outlet ground to grounding rod?

Mixed thoughts on the internet in general.  I wrote my reseller of PJ(mine is a U-power), they said don't do it.  But they also called L2 N when in split phase mode which it is not, it is just a 120v wave offset 180 degrees so L1 + L2 = 240.

I may try to put an ammeter between bat - and inverter neutral.  If I see any current crossing with the inverter under load or not I won't do it.

Entirely up to you.  I personally haven't...but don't do something just because I did or didn't 😉.

I personally do not see any problems right off with such a grounding system.  Someone with more experience in the field might weigh in differently though...

One place where DC vs AC grounding can become rather problematic is if (like me) you have DC-powered appliances.  We normally don't think anything of connecting cables between items--but if there's differing potentials, this can become very problematic.

Yeah...China just simply doesn't understand the U.S. split-phase power system.

I'd suggest a small 120v light bulb...that way any significant potential difference would cause the lamp to light up.  There shouldn't be any potential--but as I haven't seen any of the newer PJ inverters, it's awfully hard to say.

My understanding of physics and chemistry is that earth to function as a ground has to be part of the ionic or electron flow.  The flow of electrons comes from the bat's ionic flow between anode and cathode.   Earth itself isn't a reference unless it is part of the flow - which it is on the power grid - either SWER power or as a failsafe in multi wire systems.  There would never be any potential from earth to any point in the system unless ultimately unless neutral and bat - were bonded to the earth.

The internet says actual electricians mess this up all the time. 

Very curious about other's opinions on this.