LVX-6048 Ground Fault

niktak11

Solar Enthusiast
I'm having issues with my new MPP solar LVX-6048 and haven't been able to find the solution in any of the other threads in this forum. It seems like whenever the inverter is using both the solar input and the AC input for something, that it causes a ground fault (the GFCI breakers in the subpanel that's powered by the inverter trip and my tesla wall charger shows that there's a ground fault). If I turn off the solar at the disconnect the ground fault immediately goes away, or if I unplug the AC input it immediately goes away. It also goes away if the inverter is in a mode that doesn't use the AC input for anything. The inverter seems to have an issue with using the AC input when it doesn't need to but that's another story (I currently have 10x as much solar coming in as power going out to the loads yet both the inverter panel and the app show that it's drawing from the AC input for some reason). I have tried jumping the AC input and output neutrals together but that didn't fix anything. Should I do the same for the AC input and output grounds? Any other potential solutions?
 

BenQ

Solar Enthusiast
This sounds kind of like what Andy from Off Grid Garage was dealing with. Check out this video, he eventually went with a Victron inverter and it fixed the issue.
 

niktak11

Solar Enthusiast
This sounds kind of like what Andy from Off Grid Garage was dealing with. Check out this video, he eventually went with a Victron inverter and it fixed the issue.
It looks like his problem was no neutral-ground bond. Mine has a neutral-ground bond at the main panel (connected to the AC input of the inverter).
 

BenQ

Solar Enthusiast
Sounds like the automatic transfer switch in the unit isn’t working properly :( pictures of your current set up when it works and doesn’t work and posting your manual might help others solve this.
 

OffGridInTheCity

Solar Addict
I have a LV3048 in a trailer. When I plug the 120v input (to the LV3048) into a house circuit with GFCI it trips 'soon' (second or 2).
The ground is the house ground -> LV3048 -> trailer distribution box -> various things (hot water heater, TV, etc). Nothing is grounded to the trailer frame. Not sure how this could even do a trip... but might be similar to what you're reporting - so this thread is of interest to me as well.
 

eabyrd

Solar Enthusiast
I have a LV3048 in a trailer. When I plug the 120v input (to the LV3048) into a house circuit with GFCI it trips 'soon' (second or 2).
The ground is the house ground -> LV3048 -> trailer distribution box -> various things (hot water heater, TV, etc). Nothing is grounded to the trailer frame. Not sure how this could even do a trip... but might be similar to what you're reporting - so this thread is of interest to me as well.
Hi there, any luck figuring this out?
 

eabyrd

Solar Enthusiast
I'm having issues with my new MPP solar LVX-6048 and haven't been able to find the solution in any of the other threads in this forum. It seems like whenever the inverter is using both the solar input and the AC input for something, that it causes a ground fault (the GFCI breakers in the subpanel that's powered by the inverter trip and my tesla wall charger shows that there's a ground fault). If I turn off the solar at the disconnect the ground fault immediately goes away, or if I unplug the AC input it immediately goes away. It also goes away if the inverter is in a mode that doesn't use the AC input for anything. The inverter seems to have an issue with using the AC input when it doesn't need to but that's another story (I currently have 10x as much solar coming in as power going out to the loads yet both the inverter panel and the app show that it's drawing from the AC input for some reason). I have tried jumping the AC input and output neutrals together but that didn't fix anything. Should I do the same for the AC input and output grounds? Any other potential solutions?
Did you run this gremlin down?
 

niktak11

Solar Enthusiast
Hi there, any luck figuring this out?
Not yet. MP Solar requested a wiring diagram of my setup. Haven't heard back from them yet. I ended up switching out the subpanel GFCI breakers for standard breakers so I don't have to worry about the freezers turning off while I'm not home, but the Tesla charging adapter has built in GFCI protection so it still causes problems when I'm charging my car.
 

eabyrd

Solar Enthusiast
Not yet. MP Solar requested a wiring diagram of my setup. Haven't heard back from them yet. I ended up switching out the subpanel GFCI breakers for standard breakers so I don't have to worry about the freezers turning off while I'm not home, but the Tesla charging adapter has built in GFCI protection so it still causes problems when I'm charging my car.
Maybe a silly question, but have you confirmed continuity between neutral and ground at the inverter AC in and AC out? I am interested because this is my #1 contender, but if it is going to trip arc fault or GFCI breakers at random that’s a deal killer
 

niktak11

Solar Enthusiast
I received a reply from MPP solar, but it doesn't make much sense.

"Hi,
Please try this: disconnect load wires and keep only AC INPUT, BATTERY, and PV wires attached to inverter, and then verify again if the problem will go away? If so, this narrows down the cause of the leakage current to the load side and I suspect this may be the cause of it (below). The AC input N-G should not be bonded. "

Of course disconnecting the AC out gets rid of the issue. How could something detect a ground fault if it's not even plugged in? Also I'm hoping that this guy was confused about the neutral ground bond at the AC input, instead of them designing an inverter for the US market that doesn't work with US main breakers...
 

eabyrd

Solar Enthusiast
I received a reply from MPP solar, but it doesn't make much sense.

"Hi,
Please try this: disconnect load wires and keep only AC INPUT, BATTERY, and PV wires attached to inverter, and then verify again if the problem will go away? If so, this narrows down the cause of the leakage current to the load side and I suspect this may be the cause of it (below). The AC input N-G should not be bonded. "

Of course disconnecting the AC out gets rid of the issue. How could something detect a ground fault if it's not even plugged in? Also I'm hoping that this guy was confused about the neutral ground bond at the AC input, instead of them designing an inverter for the US market that doesn't work with US main breakers...
You gotta admit, no loads will fix the issue. Have you checked continuity between neutral and ground? Is your array grounded? Your battery bank?

Coming from the mobile side I specifically asked about neutral to ground bonding and was assured by Ian there was none. See below

Ed, there is no internal ground to neutral bonding.

This would be a foolish move by any manufacturer as it could cause catastrophic ground loop currents.

Ground and neutral should only be done at one central location, like a electrical distribution panel

Ian Roux
usa-mpp-solar.com / store / manuals / sales
801 403 0336
Utah USA
 

niktak11

Solar Enthusiast
Just received another reply after asking them to clarify what they are saying. They are now telling me to unbond neutral and ground in my main breaker panel 🤦‍♂️
 

Kevox

New Member
Merging utility power with inverter can get complicated, Look at how Victron accomplishes power balancing on page 4...and they are not trying to simultaneously supply grid power and inverter power...https://www.solar-electric.com/lib/wind-sun/VE-Manual-Autotransformer-32A-100A.pdf
The LVX is autotransformer based.
 

Kevox

New Member
Just received another reply after asking them to clarify what they are saying. They are now telling me to unbond neutral and ground in my main breaker panel 🤦‍♂️
In your house system, if a ground fault occurs, fault current travels through the equipment ground (ground wire, typically) back to your service panel, then through the main bonding jumper to the neutral which allows the breaker to trip, No bonding jumper means no protection. The fault will exist waiting for the circuit to be completed, Some fault current may flow but not enough to trip a breaker, Enough fault current to kill a person but not trip the breaker.
 

eabyrd

Solar Enthusiast
Any update on this. I received mine Monday, and turned it on for the first time today. It seems to work fine in battery mode, but as soon as I added line power it started cycling, and beeping. The fault light was on but I couldn’t see a fault number. It was obviously very unhappy. I double checked all my AC connections (must say I am not a fan of the terminal block).

I went into the menu and changed the mode from SUB to SBU. when I brought utility back online it didn’t cause a crisis, but then again the battery was full. I suspect that if the battery disconnected I would be right back at it

Solar isn’t even connected yet. Not sure where to go from here
 

Kevox

New Member
Any update on this. I received mine Monday, and turned it on for the first time today. It seems to work fine in battery mode, but as soon as I added line power it started cycling, and beeping. The fault light was on but I couldn’t see a fault number. It was obviously very unhappy. I double checked all my AC connections (must say I am not a fan of the terminal block).

I went into the menu and changed the mode from SUB to SBU. when I brought utility back online it didn’t cause a crisis, but then again the battery was full. I suspect that if the battery disconnected I would be right back at it

Solar isn’t even connected yet. Not sure where to go from here
Did you connect the input to 240 plus a neutral or just 129v?
 

eabyrd

Solar Enthusiast
Did you connect the input to 240 plus a neutral or just 129v?
Both input and output show ground, line1 line2, and Neutral. So it has 240 and 120

Here is my wiring currently

From main panel with bonded Neutral & Ground
Hot 1 to Inverter Input Line 1
Hot 2 to inverter input Line 2
Neutral to Inverter input N
Ground to Inverter input G

From Subpanel Unbonded
Hot 1 to Inverter output Line 1
Hot 2 to Inverter output Line 2
Neutral (unbonded) to Inverter output N
Ground (unbonded to Inverter output G

I tried running the following from the Main (bonded) panel to the subpanel based on the MPP website diagram (see below) that all shows continuity of commons & grounds, but when I did that the inverter wouldn't even start so I disconnected them.
Neutral to Subpanel Neutral (unbonded)
Ground to Subpanel Ground (unbonded)
1628858432111.png
 
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Kevox

New Member
The pictorial wiring diagram from their website does not show the same wiring as the manual I downloaded from Watts247. The terminal blocks in the manual and on my unit have G, L1, L2 and N connections for both input AC and output AC. The ground connections have continuity and also the output neutral has continuity to the ground (they are bonded internally) There is no continuity between the input and output neutrals with power off at least, but the pictorial diagram shows continuity. We could really use an actual wiring diagram showing the autotransformer connections including how bonding is achieved. I have not installed my unit yet...
 

eabyrd

Solar Enthusiast
if this thing has a bonded neutral then it’s worthless. It will never work with arc fault breakers. I was assured by MPP solar it was unbounded before I bought it. There isn’t a chassis ground either.

i have reached out to MPP solar with the above wiring description. Hoping they reply soon
 
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