EG4 Official Neutral Ground Bond Thread.

[timselectric]

Got that. I think what I'm looking for, confirm if wrong:
The "source" is typically N/G bonded. Source might be:

• Main panel (if grid tied)
• Generator (if RV) or if in a scenario with a "whole house" generator
• AIO where it's in "mobile" mode

Downstream, no bonding.

Some confusion for me where I see EG-4 cases where they are powering a panel and indicating to ground at the panel.

For Later EG-4 6500s (I think after 2/2023) there is no N/G bond screw installed. You need to install it and install mobile firmware.

Correct

 

[dcg9381]

Just reporting back. I updated my firmware to the lasted "mobile" version and had to crack open the inverter. Remove a board that's in the way and add the 2.5mm x 10mm bond screw. Once I did that, inverter tested for continuity on N/G.

For 2/2023+ inverters (at least at this time) you must do both (for mobile cases) - that is, firmware AND bond screw. This means opening the case.

Once I did that my ground fault sensitive equipment worked fine.

 

[timselectric]

For mobile installations.
I wonder if SS could make these changes before shipping. If the customer wasn't comfortable doing it.

 

[dcg9381]

For mobile installations.
I wonder if SS could make these changes before shipping. If the customer wasn't comfortable doing it.

I'd assume so if requested. But in order to be requested, need a little more transparency around how they are configured before leaving the warehouse. I'm not sure that they were expecting the grounds bond screw change. I don't think they really want consumers poking about on inverters and STILL having to warranty inverters that have been cracked open.

When we buy more EG-4 6500s, I'll definitely inquire about having them flashed to the right mobile firmware. For split phase, apparently you only ground bond the master... So you end up with a configuration matrix.

 

[Hedges]

And apply a sticker indicating which configuration.

When they get tired of modifying every unit shipped, they can redesign the board(s) so accessible as a 2-pin connector for jumper.
Or put a Molex connector on that board, and have a short whip coming out to where user could insert a shorting plug.

With the right power and coil signals on that connector, could either use internal relay for neutral connection to center tap of external transformer (if cable to handle the amps), or control an external relay to do that.

 

[timselectric]

It could all be put in the settings.

 

[timselectric]

Suggest
Setting #??
CN = common neutral
DB = dynamic bonding
And applies to master unit only.

 

[Adam De Lay]

Suggest
Setting #??
CN = common neutral
DB = dynamic bonding
And applies to master unit only.

They could even make it more "user friendly" since they're going with "Stationary" vs "Mobile" as their terminology. Then in a split phase pair, the proper settings are automatically propagated to the slave units.

 

[Hedges]

If it has available signal relays, this could be a dongle optionally added to just master unit. If not, cable pulled out from existing relay terminals.

 

[Adam De Lay]

If it has available signal relays, this could be a dongle optionally added to just master unit. If not, cable pulled out from existing relay terminals.

So many options...

 

[Mithril]

Just a thought:
In any scenario with parallel inverters where a Dynamic G-N bond would be OK/Desired it's likely this should actually be an *external* G-N bond via a compliant device.
Why? You've got 2 options; "N" number of inverters in parallel where there is only a single G-N bonding relay/contactor that is NOT rated for the full potential fault current OR Multiple G-N bonds that may or may not have equal length/resistance conductors.
This issue is not limited to EG4 so I wonder how "Tier 1" units handle it, have a G-N bonding relay/contactor rated for the maximum Amps possible from the maximum number of paralleled inverters and have only the main/master inverter bond? That feels the sanest thing and since you can (generally) limit that number in software you can (mostly) prevent non-compliance.

 

[timselectric]

There's no need for dynamic bonding in a stationary system. And mobile systems are generally small.
In a rare case of a large mobile system (emergency response teams), the entire system would require special attention.

 

[dcg9381]

There's no need for dynamic bonding in a stationary system. And mobile systems are generally small.
In a rare case of a large mobile system (emergency response teams), the entire system would require special attention.

I'm not sure what constitutes "large" but it's relatively commonplace to have RVs with inverter technology these days. I've seen battery/inverter systems capable of powering AC on rigs as small as Sprinter Vans (~20 feet) and certainly I've seen even larger systems in 5th wheels - typically for the purpose of powering a "residential" refrigerator. These have to be dynmaically bonded because they are "sometimes" charged from grid.

The most high tech sprinter I saw charged from a 400A alternator, PV, and/or grid power. In the more typical case of just PV/grid, i assume the bond is handled at the transfer switch.

 

[timselectric]

I'm not sure what constitutes "large" but it's relatively commonplace to have RVs with inverter technology these days. I've seen battery/inverter systems capable of powering AC on rigs as small as Sprinter Vans (~20 feet) and certainly I've seen even larger systems in 5th wheels - typically for the purpose of powering a "residential" refrigerator. These have to be dynmaically bonded because they are "sometimes" charged from grid.

The most high tech sprinter I saw charged from a 400A alternator, PV, and/or grid power. In the more typical case of just PV/grid, i assume the bond is handled at the transfer switch.

Anything mobile and recreational would be considered small, by me.
Large would be a disaster relief, portable (semi trailer) power station.
And they are usually isolated from "shore power".
By separate charging systems.

 

[Hedges]

RV typically connected by up to 50A plug, and N-G bond relay should be sufficient to trip that breaker (250A fast trip, 75A for a few minutes slow trip). Do any have more than that?

I could imagine yacht or something like that could be in another league.

 

[rmharrington]

The default configuration common in inverters is to have a bonding screw in place with a neutral bypass relay to support having a bond in a mobile application provided by the inverter when shore power is disconnected and use the shore bond when shore power is connected.

This is to prevent the very serious safety risk of either an unbonded mobile application or a second bond at the mobile unit a long distance away from the shore power main bond.

Hi. Just ready to fire up my two post Feb. 2023 eg4 6500 inverters. Want to make certain I rightly understand the ground bonding rules before starting. So, here's the layout.

1) The 2 eg4 6500 units wire in split-phrase to the neutral/ground isolated sub-panel with power and neutral only -- no ground connection. The neutral ground bonding occurs in the attached main panel.
2) Firmware for both eg4s are as they shipped from Signature Solar in March of this year
3) Neither eg4 feeds the main panel
4) Main panel feeds both eg4s wired complete with ground / power / neutral

Is this arrangement correct?
Do I need to change any settings on the EG4s that affect how the ground bonding is handled?
Is there any reason I need to concern myself with updating the current firmware on my two units?
AND lastly, Can I check my current firmware via the control panel rather than by connecting a computer?

These are the final question for my system. I used to go through Mason, but it seems his email is no longer in service. Please provide any necessary information to ensure I protect myself and this equipment correctly.

Thanks

 

[timselectric]

The 2 eg4 6500 units wire in split-phrase to the neutral/ground isolated sub-panel with power and neutral only -- no ground connection.

The sub panel must be grounded.

 

[rmharrington]

The sub panel must be grounded.

The sub panel is ground, just not from the inverter AC output side. This is what I have seen on multiple places. It said to ground the Inverters on the AC input lines, but not on the AC output lines. Otherwise it creates a ground loop. Did I misunderstand?

 

[timselectric]

The sub panel is ground, just not from the inverter AC output side. This is what I have seen on multiple places. It said to ground the Inverters on the AC input lines, but not on the AC output lines. Otherwise it creates a ground loop. Did I misunderstand?

That's fine. As long as everything is grounded.
It looked like you were saying that it wasn't.

 

[Hedges]

The ground wire from sub-panel (fed by inverter) ought to route in same cable/conduit as power and neutral from inverter.
I would expect it to bond to inverter chassis, and continue back to main panel in same cable/conduit and power and neutral from main panel to inverter. At main panel or main disconnect switch, ground and neutral are bonded together.

It said to ground the Inverters on the AC input lines, but not on the AC output lines.

Sunny Island has grid L/N/PE on the right, load N/L/PE on the left.
They expect us to connect ground through the inverter. Neutral too (same net goes to both terminals, not switched.)

My conduit happens to to be in a Tee configuration, so I only connected PE and N once. If there had been input and output conduit, I would have used both terminals to daisychain the wire.

The sub panel is ground, just not from the inverter AC output side. ... Otherwise it creates a ground loop. Did I misunderstand?

If sub panel is downstream of inverter (and has no other connection back to main panel), connecting ground to it through inverter wouldn't make a loop. Other configurations (including a transfer switch or interlocked breakers for bypass) would create a loop. I would let it be a loop. I don't care about loops in ground, I care about low impedance ground (which includes no airgap between hot line and ground.)

 

[gribov42]

Hi all,
I'm considering a 6000XP for my skoolie build (RV) and hit the classic neutral-bond question which led me to this thread. I saw the comments about various solutions, including making a "bonding plug" that goes into the input to bond when not in use, or just switching it on the inverter settings. I had a some ideas about solutions that I didn't see mentioned and wanted to ask if anyone has tried them:

1) What about just wiring a standard switch to bond ground/neutral when needed (I have a switch panel in my "service area" that could be used for this, with a cover to protect from accidental presses.
2) Can you change the EG4 setting for this from their wireless app? The reason I ask is because my inverter will be hidden away and it would be best to set up without needing to access.
3) If you connect your EG4 to SolarAssistant, can you change this setting from there? I'm considering setting up a touchscreen with this and that would be a good place to switch this too.

Since I will sometimes plug into shore power, and sometimes to generators, it would be good to be able to manually switch this and maybe just a switch is the easiest option.

 

[timselectric]

If the inverter doesn't provide the function.

I would use a relay, to make it automatic.
That way you don't have to remember to switch it. Or check to see if it needs to be switched. Or explain to someone else, when and if it should be switched.

 

[FilterGuy]

I have not built and tested it, but here is a design that could be used with the 6000XP:



Terminal Block:https://www.amazon.com/Assembly-Kit-DK6N-Black-Gang/dp/B0BDGML77P/
Relay: https://www.amazon.com/Baomain-Power-JQX-62F-2Z-Voltage-Electronmagnetic/dp/B09T996KNM/
Box: https://www.amazon.com/Ogrmar-Plastic-Dustproof-Junction-Enclosure/dp/B0786ZLFSV/

If shore power is present, the relay turns on. This disconnects the NG bond and creates a connection between the inverter and shore neutral.
If shore power is not present, the relay turns off. This connects the NG bond and disconnects the neutral between the inverter and shore.

 

[FilterGuy]

If there is an automatic 3-pole transfer switch that switches neutral, it can be used for doing the dynamic bonding:


When there is no shore power the relay is off and the inverter circuit is connected to the Generator.

If the generator is hard wired, the N-G bond can be anyplace in the circuit. If the generator is connected with a plug, the N-G bond should be at the transfer switch or the associated plug. Not in the generator. (This ensures the bond is present even if the generator is not plugged in.

 

[gribov42]

I don't think I'd actually want it to be fully automatic on shore power input though - As others have pointed out in this thread, if you plug into shore you want to disconnect your bond, but if you plug a generator into the same AC input you'd actually want to keep it bonded. So it might be better to do it manually to support using a generator and shore power IMO.

Although I see what you're suggesting actually in the second picture, this would require having separate inputs for gen/shore which I wasn't planning on. Does someone sell a bonding relay box like this, or is this a proposed circuit to make?