MPP Solar LV1012 N-G Bond

thetimbo

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Does the LV1012 have an N-G Bond while on Battery, or does the relay bond the N-G while on Shore Power (a small generator)?
I see lots of discussion about the LV2424, but nothing on the LV1012.

Tim
 

JAS

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I have the same unit and got mixed answers. However, I believe it bonds while on battery and releases that bond when on pass through AC (Shore Power)
 

thetimbo

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Thanks for reply. I appreciate your help. So, you didn't bond to ground anywhere on your AC Output? And did you jumper the AC input & output Neutrals like all the lv2424 folks do? Finally, did you earth the inverter box to a grounding rod? If so, where on the box did you ground it?
Tim
 

12VoltInstalls

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I recently installed the MK version of this.
I did not do the good procedure and test the unit like I know I should have.
I’ll do it tonight.

Nevertheless- disconcerting questions you asked.
So, you didn't bond to ground anywhere on your AC Output?
If the inverter output is bonded you should never bond elsewhere. If it is not bonded internally (I’m thinking/hoping it is switched) you should not bond elsewhere than the incoming AC load center depending on the pass through / switching convention it uses.
And did you jumper the AC input & output Neutrals like all the lv2424 folks do?
You probably shouldn’t do that unless you know how it handles the N/G bond or switching.
Finally, did you earth the inverter box to a grounding rod? If so, where on the box did you ground it?
That isn’t a good idea, either. I remember putting a meter on a case screw and batt(-) terminal but can’t remember but I’m assuming case is bare/grn/neg to DC because I think I’d remember if it were open. ??? I’d have to check again.

I don’t know if case is closed between it and 120V but again: depending on how it handles grid bare/green that could (would likely) create an in-fault ground loop; not good.

My assumption is that 120VAC ground/bare/green is hard to grid grd/grn to find itself together in the entrance panel.
 

thetimbo

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I've seen people claim they've bonded those in/out neutrals because it's claimed to always be a good idea. I myself am unsure.
For earthing the LV1012, doesn't one have to? Where would the system earth any faults, otherwise? Again, I'm unsure, but would
suspect this to be the case.
Tim
 

JAS

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Thanks for reply. I appreciate your help. So, you didn't bond to ground anywhere on your AC Output? And did you jumper the AC input & output Neutrals like all the lv2424 folks do? Finally, did you earth the inverter box to a grounding rod? If so, where on the box did you ground it?
Tim
No, I am not bonding anywhere on the AC output. No, I did not jumper the Neutrals. No, I did not ground the box (as you said, there is no provision for this)... Based on Will's videos, I'm assuming the earth ground is coming from the AC input. (In my case my main service panel). Not sure what you would do if you are not using AC input at all?
 

12VoltInstalls

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No, I am not bonding anywhere on the AC output. No, I did not jumper the Neutrals. No, I did not ground the box (as you said, there is no provision for this)... Based on Will's videos, I'm assuming the earth ground is coming from the AC input. (In my case my main service panel). Not sure what you would do if you are not using AC input at all?
Actually you hit all the important points!

Doing nothing may not be the right thing to do but it is less wrong than doing the wrong thing.

If N-G is open and static grid-down(no grid) and grid-up then there’s conversations to be had. Simply bypassing or otherwise adding a wire may be very wrong and definitely more wrong than doing nothing.

That’s not to say something shouldn’t be done.
Not sure what you would do if you are not using AC input at all?
If it were open N-G something should be done. Where? At breaker panel or in the unit but not both. That’s only for 100% no grid off grid. With a generator usage you’d have to figure that out too. Because you’d only want one ground point connected to N and that at the ‘source.’

Since it has a “transfer switch” I’m thinking the ground is handled correctly. If I get home early enough I’ll put a meter on it.
 
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thetimbo

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Thanks again for the replies. I'm going to be completely off-grid with my LV1012. If needed, a small inverter generator will be my back-up to recharge the batteries thru the AC Input, if needed. If the AIO bonds N-G while on battery, I'd want to bond a lug to the AOI's case, then ground it to earth via a rod. In the event I needed to feed the drained batteries with my "floating neutral" generator, I'd bond a ground wire to the gererator's chassis and pull it to my system's ground rod. And then my question: "If the AIO bonds N-G while on battery". If not, I'll bond the N-G downstream from the AC Output.
 

Bud Martin

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I have 1012MS and MK running in off grid, the chassis is connected to the AC input/output ground, you can easily test that with Ohm meter. The Neutral of the output is bonded to Ground via relay when it is on inverter mode, you can verify that when you measure the AC Voltage between N-G, L-G.
 

12VoltInstalls

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I'd want to bond a lug to the AOI's case, then ground it to earth via a rod.
You might want to but a standalone offgrid system? I don’t think you should drive a ground rod. There’s opinions on that but adding a ground rod? What does that do? Really nothing electrical. None of your power will have anything to do with earth.
@timselectric please weigh in.
I know that I’ve been told in the past to ground things to dirt but I’m pretty dang sure an offgrid box has no reason to go frolicking in dirt.
 

thetimbo

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BudMartin : So had you earthed the inverter to a rod? Or is that inadvisable in our Application?

12VoltInstalls : Could you tell me why running the inverter chassis to a rod isn't beneficial?

I'm new to electrical, but learning fast.
Thanks
Tim
 

12VoltInstalls

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Could you tell me why running the inverter chassis to a rod isn't beneficial?

Because in an offgrid system there is no circuit to the dirt. It has no point. Think about construction trailers, campers, RVs- they don’t have a ground rod.

If they have shorepower the ground is passed to the pedestal not the dirt or the ‘vehicle’ frame.

The bare/green/ground is pathed to the source.

There is “lightning” mitigation which imho should be grounded at the array frames (I don’t remember the mike holt perspective) and not electrically to the inverter other than the PV wires. Although there is a code situation I cannot remember at the moment about grounding the array to dirt with an insulated ground wire from the array to the entrance panel ground rod. That’s for grid interactive systems.

But a standalone with no grid in sight has no electrical potential to dirt other than static or lightning which I guess sometimes is the same thing. So if there is no circuit you’re just as well of grounding to a house plant. @timselectric
 

timselectric

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A couple of questions.
Is the inverter connected to grid?
Can I get a brief description of your system?
I'm not sure about that model, for any particulars.
Going to look it up.
 

12VoltInstalls

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not sure about that model, for any particulars
Here you go man!
I’m on a 1-1/2hr drive home

Is the inverter connected to grid?
I believe OP needs to verify. @thetimbo
Technically mine is grid connected when I turn on the incoming switch.
I use it as a fast charger with low light days we get a lot of lately and supplemented 40-200W over the winter.

But I’m set up to be off grid.

OP I believe was off grid.
 
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timselectric

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There's nothing in the installation manual, that tells if it performs a N/G bond when in battery mode.
This will have to be tested, if no one else can verify it.
 

thetimbo

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Yes, my 1kw LV1012 all-in-one is not grid tied. I will plug my AC Input into my 2000w inverter jenny to recharge my batteries during lengthy bad weather. The distributor, Ian Roux, told me today that the N-G is bonded while on battery, and switches off-bond when charging thru the AC Input (my generator). If I tie the PV panels to a rod for lightning drainage, should I/could I also ground the AIO chassis to the same rod?

Appreciate your Advice!
Tim
 

timselectric

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You should install a ground rod, at the inverter location. Run a #6 wire from the ground rod to a ground bar (this is the "main ground bar) , mounted somewhere close to the inverter. All grounding conductors should be connected to this bar. (Inverter, solar array, AC loads panel, generator) if installing an AC loads panel, the ground bar in it can serve as this main ground bar.

Next questions:
How are you going to make the connection between the generator and inverter input?
And, does your generator have a N/G bonded output?
 

JAS

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There's nothing in the installation manual, that tells if it performs a N/G bond when in battery mode.
This will have to be tested, if no one else can verify it.
I contacted MPP support and they told me that it does bond N/G while Inverting from battery. I wasn't sure this could be tested while the unit was "hot" (without smoking my multimeter)? So I didn't try :)
 

Bud Martin

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I contacted MPP support and they told me that it does bond N/G while Inverting from battery. I wasn't sure this could be tested while the unit was "hot" (without smoking my multimeter)? So I didn't try :)
Just use AC Voltmeter to test the AC Voltage between G and N, G and L.
 

timselectric

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I contacted MPP support and they told me that it does bond N/G while Inverting from battery. I wasn't sure this could be tested while the unit was "hot" (without smoking my multimeter)? So I didn't try :)
Thanks for the information.
FYI, this can only be tested with the unit running in battery mode and bypass mode.
(Without the input ground connected)
 
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