Grounding- no idea what they're talking about!

[pda1]

My system is 2kW feeding two series Battleborn's for a 24v-100ah storage.

I'll be installing a Multiplus Compact 24-2000 (2000-50a) inverter/charger

Now that part I've become more and more confused about is the grounding of the entire system- both AC portion and DC portion.

I assume this parts correct- the AC portion is grounded through the AC junction boxes with the ground wire going back to the MAINS panel.
If that's incorrect- tell me how to correct it (not theoretical- practical).
Here's what Victron says;

This is a Safety Class I product (supplied with a protective grounding terminal). Uninterruptible protective grounding must be provided at the AC input and/or output teminals and/or chassis grounding point located externally on the product.

So here comes the harder part- the DC grounding- no idea what I'm supposed to do.
The Multiplus manual says;

Ground relay (see appendix B) With this relay (H), the neutral conductor of the AC output is grounded to the chassis when the back-feed safety relay is open. This ensures the correct operation of earth leakage circuit breakers in the output. If a non-grounded output is required during inverter operation, this function must be turned off. (See also Section 4.5) Not adjustable with DIP switches.


This is a Safety Class I product (supplied with a protective grounding terminal). Uninterruptible protective grounding must be provided at the AC input and/or output terminals. Alternatively the grounding point located externally on the product may be used. Whenever it is likely that the grounding protection has been damaged, the product must be turned off and secured against unintended operation; please contact qualified
service staff.


Another problem is that of DC grounding of my system. Yes, I know the panels don't get grounded. How about some sort of ground rod with the BMV-712 attached to it with a cable?

I've read and have tried to understand Victron's wiring manual but haven't learned too much.

Looking for help....

Thanks

P.S. Have seen way too many youtube videos about the subject. I suppose it's a liability issue- wrong advice and God only knows you can get sued.

 

[pda1]

Geez.....Will does it again!!!

Very helpful....so far

 

[timselectric]

I assume this parts correct- the AC portion is grounded through the AC junction boxes with the ground wire going back to the MAINS panel.

Correct

So here comes the harder part- the DC grounding- no idea what I'm supposed to do.

For Victron only. And if in a mobile installation. (RV, Boat, ect)
The negative side of the battery system is connected to the chassis (frame). This is not required in a permanent location installation (home, business) .

Ground relay (see appendix B) With this relay (H), the neutral conductor of the AC output is grounded to the chassis when the back-feed safety relay is open. This ensures the correct operation of earth leakage circuit breakers in the output. If a non-grounded output is required during inverter operation, this function must be turned off. (See also Section 4.5) Not adjustable with DIP switches.

This is referring to the N/G bond.
Which is provided by the main service panel. But, is disconnected when the inverter switches to inverter power. So, it creates a new N/G bond with the relay.
You can only have one N/G bond at any time.

As far as a ground rod.
You should already have one at the main panel.

 

[pda1]

Whoops. This system is installed in my house- not mobile.

 

[pda1]

Correct

For Victron only. And if in a mobile installation. (RV, Boat, ect)
The negative side of the battery system is connected to the chassis (frame). This is not required in a permanent location installation (home, business) .

This is referring to the N/G bond.
Which is provided by the main service panel. But, is disconnected when the inverter switches to inverter power. So, it creates a new N/G bond with the relay.
You can only have one N/G bond at any time.

As far as a ground rod.
You should already have one at the main panel.

Yes, there's a ground rod at our house's main breaker panel. However, I have put a 12awg wire from the BMV-712 to a cold water pipe (copper).

Now, you mentioned "You can only have one N/G bond at any time." Would you please explain this relative to when the inverter turns on? That is- I have no idea if I'm supposed to ground, or connect some HUGE wire (#2 in my situation with the Multiplus) to ground on the Multiplus's ground cabinet terminal (which it does have).

So it seems I have the AC grounding portion of the system correct. It's just the DC portion of the system and the Multiplus that has got me confused.

 

[timselectric]

Yes, there's a ground rod at our house's main breaker panel. However, I have put a 12awg wire from the BMV-712 to a cold water pipe (copper).

I'm not familiar with all of the victron equipment. But I thought that the 712 was a battery monitor.
If so, it shouldn't be grounded.

Now, you mentioned "You can only have one N/G bond at any time." Would you please explain this relative to when the inverter turns on?

Your main panel has a N/G bond. In bypass mode (grid feeding loads), the inverter passes the mains N/G bond through to the loads.
In inverter mode. It disconnects from the main panel. And creates a new N/G bond for the loads.

That is- I have no idea if I'm supposed to ground, or connect some HUGE wire (#2 in my situation with the Multiplus) to ground on the Multiplus's ground cabinet terminal (which it does have).

No
That is for a mobile application.

So it seems I have the AC grounding portion of the system correct. It's just the DC portion of the system and the Multiplus that has got me confused.

Do not ground any part of the DC system wiring.
Only ground the metal enclosues, frames, and racking.

 

[pda1]

I'm not familiar with all of the victron equipment. But I thought that the 712 was a battery monitor.
If so, it shouldn't be grounded.


Your main panel has a N/G bond. In bypass mode (grid feeding loads), the inverter passes the mains N/G bond through to the loads.
In inverter mode. It disconnects from the main panel. And creates a new N/G bond for the loads.

No
That is for a mobile application.

Do not ground any part of the DC system wiring.
Only ground the metal enclosues, frames, and racking.

Is it correct to say, I should ground the steel cabinet in which all of my solar devices are located (MPPT, bus bars, switches)? And that grounding is done with the ground rod and heavy cable connecting them together electrically?

Oh, here's the manual for the Victron Multiplus 2000-50
Multiplus 24-2000

 

[pda1]

You're correct- the BMV-712 is a battery monitor.

 

[timselectric]

Is it correct to say, I should ground the steel cabinet in which all of my solar devices are located (MPPT, bus bars, switches)?

Yes

And that grounding is done with the ground rod and heavy cable connecting them together electrically?

No
Connect it to your existing grounding system.
Without knowing how your system will be situated, it's hard to say what is the easiest way to do this.
But the ground wire going from the main panel to the inverter is the ground for your new system.

 

[pda1]

Yes

No
Connect it to your existing grounding system.
Without knowing how your system will be situated, it's hard to say what is the easiest way to do this.
But the ground wire going from the main panel to the inverter is the ground for your new system.

Ok. I see. The cabinet and Multiplus will be grounded to the ground going back to the main house's breaker panel.

Thanks

 

[Adam De Lay]

If your connecting to your grid connection at your house (that already has a ground/neutral bond), you’ll want to use the VE Config software (you might be able to use Victron Connect app, not sure) to disable the g/n bond in the inverter. That way you only have the one from your grid panel in your environment.

 

[pda1]

If your connecting to your grid connection at your house (that already has a ground/neutral bond), you’ll want to use the VE Config software (you might be able to use Victron Connect app, not sure) to disable the g/n bond in the inverter. That way you only have the one from your grid panel in your environment.

Ok. I do have the VE Config stuff.....will check that once it has been set up.

 

[timselectric]

If your connecting to your grid connection at your house (that already has a ground/neutral bond), you’ll want to use the VE Config software (you might be able to use Victron Connect app, not sure) to disable the g/n bond in the inverter. That way you only have the one from your grid panel in your environment.

You don't want to disable it.
It has separate input and output neutral connections. (Not designed for common neutral setup)
If I'm not mistaken.

 

[pda1]

Uh oh.....confusion.

 

[Adam De Lay]

You don't want to disable it.
It has separate input and output neutral connections. (Not designed for common neutral setup)
If I'm not mistaken.

No, you’re correct. The L and N for the AC-In are connected via a relay which is only closed when your in pass through mode.

I have to remember that my setup is unique in how my AC panels are connected. Since my inverters are powering one of my house sub-panels using a generator interlock kit, my neutrals are all connected together, so I had to disable the bond in both inverters.

Thanks @timselectric

 

[pda1]

I'm lost. What am I supposed to do with grounding?

Ok. So, the incoming AC from the grid to the Multiplus is grounded using the AC in and out ground wire which will be attached to the AC IN junction box (not on the MP) and the AC OUT junction box (not on the MP)

Is this correct- the multiplus will have ONLY its chassis ground connected to the negative ground on the battery or the battery bus bar.

I hope that's correct...


I'm going to post this over at Victron. In truth I was reading the Victron Wiring manual which is very helpful....

Life would be easier is the MP instructions said..."given these setup situations...do this".

 

[Adam De Lay]

Is this for a house or a mobile/rv setup?

 

[pda1]

A house.

 

[timselectric]

Is this correct- the multiplus will have ONLY its chassis ground connected to the negative ground on the battery or the battery bus bar.

Do not connect any DC conductors to ground.
I believe that we have covered everything else, above. But feel free to ask, if we missed anything.

 

[Adam De Lay]

Thanks.

The ground connections on the MP are all connected together. So when you connect your AC In, you will be grounded back to your main system ground.

Like @timselectric said, you don’t need to ground the negative battery connection because it’s a stationary environment.