Grounding growatt, generator, on vehicle.

[mtts]

Ian at watts247 had me tie a jumper wire between neutral and ground, at the bus bars in the vehicle main AC panel, which is fed by the growatt, because there was no neutral-ground bond in the system at the time.

Vehicle has a 3kw gasoline inverter generator, that has no neutral-ground bond, feeding a GroWatt SPF 3000 TL LVM ES, 1800w of panels, 10kw of EG4 LFPO. What I don't know, and please reply in plain english, is:

if the breaker box panel which is on the AC output side of the inverter, has the neutral-ground bond, is that bad? Should the bond instead, be made inside the growatt, where the AC-IN and AC-OUT is? Because Code or best practices seem to assume that the neutral is bonded to the ground on the INPUT side, e.g. at a conventional main breaker panel, ahead of the Growatt, not afterwards. Another way of saying is, on the supply side or grid/generator side, not the load side.

Additionally, should the AC-IN and AC-OUT earth grounds be jumpered inside the Growatt lower panel where the wiring connections are made? Or does the growatt handle that?

Please, answer in plain english: No electrical abbreviations that aren't common knowledge among ordinary people. I've read, and tried to read, threads on this, including an enormously complex but well-intentioned 'grounding made simple' that was, in my opinion, anything but simple.

Questions:
Where do I put a short length of wire to jumper connections? Panel? Growatt? Generator? Between which terminals?

Do I need a grounding rod, and if so, where, on what piece of equipment, do I attach the grounding wire to?

The generator is on the roof, securely mounted within metal feet, that were part of a server rack. It is on a metal lattice rack that is bonded to the steel frame of the vehicle (although the vehicle has composite walls, so the frame is internal). I believe the generator has a grounding lug. Should that be tied with a wire electrically, to the metal frame it's sitting on?

There is some documentation on how to bond the neutral to ground, within the generator, but that would require disassembly. I'd like to avoid that. There is a 30-amp plug plugged into the TT outlet on the generator, with the other end wired straight into the growatt AC-IN. Do you suggest jumpering it's neutral and ground inside where it connects to the growatt terminals? I don't plan on plugging this into grid, ever. I have in the past, but it's not likely into the future.

Thank you, in advance.

 

[Samsonite801]

Based on NEC guidelines, the N-G bond should be as close to the power source as reasonably possible, and there should only be one N-G bond in the whole system. The idea of the ground is to provide a separate path in case of an appliance short, to make it back to the power source return (neutral), so the idea is to keep the two paths separated for as long of distance as possible, but the purpose of joining them is so it can return to the power source so if a fault (short) occurs, it will be enough current to trip the breaker, and remove the fault (danger).

On an RV, just treat the ground like you would in a house, keep them separate, except that it is a non-Earthed grounding, so where they join, then ground upstream (on the AC input), may normally go to a ground pole in a house for example. Instead of running the ground to a ground pole, just ground the wire (that would go to the ground pole in a home) to the chassis of the vehicle.

N-G bond can be made with a simple horseshoe-bent wire to connect on the output terminals of the inverter. If the inverter is feeding directly to the AC panel with no other connections in the middle, it might be suitable to just make the N-G bond in the AC panel (although it is not at the closest point to the power source).

How does the generator tie into the system? Via ATS switcher or is it wired onto the AC input of the inverter or something?

 

[mtts]

Just saw this: The generator has a 30 amp TT outlet, and there is a molded male plug ending in a cut-off cord, that is then soldered on it's ends, so it's not stranded (just like using a ferrule), wired directly into the Growatt AC-IN. There is no bond between ground (i think there is an accessible lug for that on the generator) and the vehicle chassis.

I'm getting that there should be a generator-chassis bond.

 

[12VoltInstalls]

don't plan on plugging this into grid, ever. I have in the past, but it's not likely into the future.

The problem with that is you get a potentially lethal situation if you someday connect to the grid with the N-G made in the RV panel. Because Grn/bare/ground could then be carrying current

 

[mtts]

So you're saying it's an advantage to bond within the generator itself.

I can put a label on the growatt as a warning to future owners, that there is a ground neutral bond in the growatt terminals on ac in so they know to disconnect it if going into a mains box.

 

[Samsonite801]

So you're saying it's an advantage to bond within the generator itself.

I can put a label on the growatt as a warning to future owners, that there is a ground neutral bond in the growatt terminals on ac in so they know to disconnect it if going into a mains box.

The N-G bond is usually supposed to change depending one which device is providing the power at the given time. Most all-in-one style inverters should have the N-G bond screw put in them on the main board, and then they have an onboard relay in them to disconnect the N-G bond only when the inverter is in bypass (grid power mode), which makes the new N-G bond location to be provided from the upstream power source.

So then when the generator circuit gets engaged (by ATS, where the ATS is capable of opening and closing neutral), it would have the active N-G bond. The generator wiring and grounding depends on whether or not you determine it to be a separately derived power source or if not then just ground it like you would an appliance.

Read more about separately derived systems:

separately derived system grounding - Google Search

More info:

is a generator a separately derived system - Google Search

 

[eXodus]

My Onan RV generator has ground neutral bond.

My Growatt plugs with 30A plug either into an outlet from the grid or and outlet in the wire box which is fed by this generator.

So I have N-G bond every time I'm plugged in and only in the few seconds when I'm changing moving the cord from one outlet to another there is no bond.

 

[12VoltInstalls]

can put a label on the growatt

I’d either do a transfer switch approach or three separate ‘source’ plugins (gen, grid, and neither/ where neither contains no power source but does bond N-G directly to the breaker panel. From reading above it appears the growat does not establish N-G bond from a couple posts, so you have to do it someplace.

 

[eXodus]

There is no bond between ground (i think there is an accessible lug for that on the generator) and the vehicle chassis.

I'm getting that there should be a generator-chassis bond.

My Onan Generator has a giant Black cable to the chassis of the RV- Yours must have to, It's started by the 12V system, so it must be bonded with the RV body. Otherwise the starter would not turn.

 

[mtts]

Correct: There is an old school onboard onan. Not being used.

Long ago, got a champion inverter generator from a pawn for $500. Power for it's starter battery is routed into the cabin, and the onan generator fuel pump is used to lift the fuel up. A few 2-way valves from Aircraft Spruce route the fuel.

Lots of people with older rigs get an aftermarket Honda inverter generator, or yamaha or champion, because an un-rebuilt pre-cummins onan, typically is loud and leaks oil. Runs like a beast tho. Will keep it around; it's not in the way. I've seen the same model re-done, and you couldn't tell it was running unless you were 5 feet away.

 

[eXodus]

I've seen the same model re-done, and you couldn't tell it was running unless you were 5 feet away.

how/where who do you rebuild an Onan to get it more quiet? I hardly use ours, because the exhaust is leaking into interior of the RV. Would need to pull it some day anyhow. I was toying with the idea of just selling it and putting in another 10-15 kWh of batteries and a larger 24V alternator and charge directly from the main engine.

But when I could get he onan more quiet - that would be reason to keep it.

 

[vbadov]

Oh my God it's so difficult to figure out even with the simple stuff. Not the electrical peoples abbreviations for everything. I don't think I'm going to ever be able to figure out this grounding stuff. I never even realize it's so important when I'm trying to put in my solar. I sure do understand the original post on this thread. Definitely need it explained in simpleton terms.?

 

[mtts]

how/where who do you rebuild an Onan to get it more quiet?

This is offtopic. I don't know who did the work on his (identical genset to mine, same model, year etc).
Start on smokstak https://www.smokstak.com/forum/forums/onan-generators.1/ and find someone (usually retired) in your area, who has competence working on the pre-Cummings Onan generators [which is what I assume you have, but don't know]. Everything after Cummings bought Onan, goes like this: buy a new generator (from us). While the older ones are well-designed workhorses, the 'modern' service facility isn't going to have someone who knows, or is interested in working on one, even if you pay their hourly rate. Cummings changed the design of theirs quite a bit. The older ones really are bullet-proof and worth keeping around.

 

[12VoltInstalls]

Cummings bought Onan

Cummins