Electrical/Solar help needed

I am far from the energy industry, but circumstances force me to prepare for winter and the summer blackout showed that my old scheme for operating a gas boiler from a car battery and a UPS simply will not work since there is no time to charge the lead battery.  Therefore, a decision was made and a custom LifePo4 48 v 100 A 5 kW assembly and a 6.2 kW Powmr solar inverter were purchased.  Unfortunately, I am far from an electrician, but since there are currently no free installers, I will start with placement and gradually assemble the system.  I decided to place it in a small corridor at the entrance to the ground floor, there is a high ceiling and a stable temperature throughout the year, since the main panel is located on an unheated veranda, which is hot in summer and sub-zero in winter.

I want to place it on the far wall, it will be convenient to run the cables from the main meter there, the wall is made of OSB, so I’ll remove the decorative boards and stick ceramic tiles so that the surface is non-flammable

The first question that I am trying to solve is the protection between the solar inverter powmr 6.2 kW and lithium phosphate 48v 100A 5 kW, how to properly create the protection, install a 200 A circuit breaker and a 500 A fuse of a constant current closer to the battery on the cable + or on -?.  GP chat gave me the answer, is this correct or not?
 1. Positive Circuit Breaker (200A): Location: The circuit breaker is installed as close as possible to the positive terminal of the battery. Function: It protects the system from short circuit and overload.  In the event of excessive current (for example, a short circuit), the circuit breaker will operate and disconnect the circuit, preventing damage to components.2.  Positive Fuse (500 A): Location: The fuse is also located on the positive wire, but after the circuit breaker. Function: The fuse provides additional protection against extremely high currents that can damage equipment or cause a fire.  It is designed to operate at even higher currents than the automatic one.3.  Negative wire: Nothing installed: Usually no protection devices are installed on the negative wire, since all protection is usually concentrated on the positive wire.  The negative wire is usually connected directly to the inverter and battery.4.  The main advantages of this arrangement are: Safety: This configuration provides maximum protection for both the battery and the entire system. Compliance with standards: Installation of protection on the positive wire complies with electrical standards and recommendations. Reliability: The circuit breaker and fuse provide dual protection against overloads and short circuits.

I am not an electrician either.

But I think you might attract more help if you change the title of this thread to something like "Electrical/Solar help needed".

Good luck!

Thank you, how can I change the topic title?

Let's do a little bit of math.  The max draw on the inverter is 6.2kW, or 6,200W.  Assuming the battery drops down to 48V, the maximal amp draw to make 6200W is 6200W/48V = 129A.  Looking at the wire included with the inverter, I am quite suspicious!  That looks like 4 gauge to me?  Can you please confirm the wire gauge before going further?

That is a cheap low-budget Chinese inverter, who can not be trusted to market safe and functional products.  I would look into upgrading the wire immediately.  Take a look at this ampicity chart.  The chart suggests to handle your amperage, you need at least 0 or better 00 gauge wire.

Remember, the breaker/fuse protects the wire, not the equipment.  To safely handle a 129A load, I think a 150A breaker/fuse is appropriate.  No way I would use a 500A part.

Now, that inverter is an AiO unit (all in one) that includes a MPPT charge controller?  Could you post the specs on the controller section?  Assuming it will charge your battery at up to 60-80A, and you want to de-rate output to 85% for real-world conditions, starting at 50V, that works out to be (60A X 50V)/85% = 3530W of panels.  With a 80A limit it's (80A X 50V)/85% = 4700W of panels.  We need to know the voltage limit of your controller to determine how many panels you can put in series.

Assuming your Voc limit is 150V, three 250W high-voltage residential panels in series would make a nice single string.  Four parallel strings of three panels each would be good for a 60A controller.

Don't buy 12V panels, and don't buy through the mail, because shipping is a killer.  Buy locally off of Craigslist with cash and carry panels.  Bring a volt meter with you if you question the quality.  Don't buy anything with a Voc more than 2-3V less than what's posted on the back of the panel.

The 100A battery bank you bought is very small.  Assuming you don't want to charge it all the way to 100%, and don't want to deplete it less than 20%, then you only have ~3300Wh of useable power.  That's not much.  I'm finding at my own cabin, just living a regular lifestyle with a refrigerator, lights, TV, and some computer time, I'm consuming about 4kWh of power per day.  I'd expect you to consume about the same.  That means one single cloudy/rainy day, and that battery is totally dead.

Adding more watts of solar can help with that.  With my system, I'm using virtual tracking to add watts to my system.  That means I have additional solar arrays facing East and West to complement my South facing arrays.  No single array orientation will overload my controller with too many amps, because not all the panels are at full output at the same time.  But, on cloudy days when the light is low but indirect, the extra panels help me make enough power, even in the rain.

Chat GPT is not a good choice for electrical information. It cannot be relied upon for technical details that might cause a fire or injury.


You need to size your fuse to protect your wiring, and to size your wiring to suit the maximum current.

I personally do not install cheap chinese fuses, fuseholders, breakers, relays, etc.. I have had them melt/burn up far below their rated capacity, after working fine for months on end. I am not sure if I'd prefer a cheapo fuse/breaker to none at all.. but I wouldn't run either option in anything but a crisis.

With lithium of any sort you should consider the maximum interrupting current rating of protection devices; there are plenty of fuses and breakers that are rated high enough in terms of max amps, but they cannot all be relied upon not to short when faced with the massive potential current of a lithium battery.


A good source for info specific to this topic is Will Prowse's DIY solar forum; https://diysolarforum.com.

D Nikolls wrote:Chat GPT is not a good choice for electrical information. It cannot be relied upon for technical details that might cause a fire or injury.


You need to size your fuse to protect your wiring, and to size your wiring to suit the maximum current.

I personally do not install cheap chinese fuses, fuseholders, breakers, relays, etc.. I have had them melt/burn up far below their rated capacity, after working fine for months on end. I am not sure if I'd prefer a cheapo fuse/breaker to none at all.. but I wouldn't run either option in anything but a crisis.

With lithium of any sort you should consider the maximum interrupting current rating of protection devices; there are plenty of fuses and breakers that are rated high enough in terms of max amps, but they cannot all be relied upon not to short when faced with the massive potential current of a lithium battery.


A good source for info specific to this topic is Will Prowse's DIY solar forum; https://diysolarforum.com.

listen to this advice it is bang on - cheap ANYTHING will put you in danger - as will incorrect information.

Will Prowse's site is great, another great tutorial site with diagrams is Nate @ explorist.life. here is a link to low res diagrams with fuse/breaker placements - start there:

https://explorist.life/solarwiringdiagrams/

you have not listed your input (solar, How much) and your battery cables seem a bit "thin" etc. breakers and fuses are tricky - to small and the trip all the time.. to big and you may have worse problems.

draw out a diagram end to end of what you plan and build piece by piece and buy quality components - most manufacturers have excellent install videos.

PLEASE be careful - this is one area of homesteading not to do on the cheap - good luck!

i see your location is Ukraine - that has to be tough, i am sorry - still, do what you can to protect your system accordingly - peace!

Wiring diagram, adding manual circuit breakers will help you perform maintenance.

D Nikolls wrote:Chat GPT is not a good choice for electrical information. It cannot be relied upon for technical details that might cause a fire or injury.


You need to size your fuse to protect your wiring, and to size your wiring to suit the maximum current.

I personally do not install cheap chinese fuses, fuseholders, breakers, relays, etc.. I have had them melt/burn up far below their rated capacity, after working fine for months on end. I am not sure if I'd prefer a cheapo fuse/breaker to none at all.. but I wouldn't run either option in anything but a crisis.

With lithium of any sort you should consider the maximum interrupting current rating of protection devices; there are plenty of fuses and breakers that are rated high enough in terms of max amps, but they cannot all be relied upon not to short when faced with the massive potential current of a lithium battery.


A good source for info specific to this topic is Will Prowse's DIY solar forum; https://diysolarforum.com.

https://amperok.com.ua/provid-pv-3-25-chervonyi-zzkm-15508?gclid=Cj0KCQjwiOy1BhDCARIsADGvQnDj39zCGLd1gIQnAjA-mqbSt5hJCb_cCzv-TWn7TylGYc436rxX_XYaAiEQEALw_wcB
cable marking (pv 3) 25, core cross-section 25 mm

battery parameters and inverter label

Looking at your wire pic, you do NOT measure the thickness of the wire including the insulation.  You need to measure the thickness of the copper wire itself.  Your pic is a bit blurry, but it looks like the thickness with the insulation is ~7mm.  Assuming that the plastic is ~1mm thick, that means you are likely to have a copper wire that's maybe 5mm in diameter.  Referring back to the chart on wire gauge above, that looks like it's likely to be either 6 gauge, or 4 gauge (American scale).  I'd say thats totally inadequate for supplying your inverter with power.  Maybe it's OK to use it just to turn the inverter on, and check for power, but no way would I ever try to apply a full load to that inverter, with that wire.  Since the wire appears to be originally attached to the battery, instead of the inverter itself, I'm expecting that the battery selected was originally designed for a smaller application.  That goes along the lines of what I mentioned before, that this battery is too small for your application.

Looking at the MPPT section of your AiO, it appears that the operating voltage is between 90VDC and 500VDC.  That means my example above with three panels in series might not be appropriate for your electronics.  Having only three 30V panels in series might not guarranty that you supply >90VDC at all times.  It would be better to use at least four 30V panels to get at least 120VDC.  

I'm focusing on the 30V panels mostly because that is the common variety that appears most abundant right now, with many going for only 30-40$ right now.  Maybe higher in Ukraine?  It appears that your MPPT's optimal voltage is around 240VDC, so you could go with up to 8 of those panels in series to make that voltage.  I prefer ground mounts, rather than putting panels on the roof, and the most I've built now is an array frame that can hold 6 residential panels.  That would be ~180V (1500W), which would work well for you.  If you build rotating mounts like mine, you can rotate it East in morning, and West in the afternoon, resulting in more total power.

I'd consider building the array frame like I've pic below, though with such a small battery, the extra watts won't get you much.  You really need a bigger battery to take advantage of extra solar.

Michael Qulek wrote:Looking at your wire pic, you do NOT measure the thickness of the wire including the insulation.  You need to measure the thickness of the copper wire itself.  Your pic is a bit blurry, but it looks like the thickness with the insulation is ~7mm.  Assuming that the plastic is ~1mm thick, that means you are likely to have a copper wire that's maybe 5mm in diameter.  Referring back to the chart on wire gauge above, that looks like it's likely to be either 6 gauge, or 4 gauge (American scale).  I'd say thats totally inadequate for supplying your inverter with power.  Maybe it's OK to use it just to turn the inverter on, and check for power, but no way would I ever try to apply a full load to that inverter, with that wire.  Since the wire appears to be originally attached to the battery, instead of the inverter itself, I'm expecting that the battery selected was originally designed for a smaller application.  That goes along the lines of what I mentioned before, that this battery is too small for your application.

Looking at the MPPT section of your AiO, it appears that the operating voltage is between 90VDC and 500VDC.  That means my example above with three panels in series might not be appropriate for your electronics.  Having only three 30V panels in series might not guarranty that you supply >90VDC at all times.  It would be better to use at least four 30V panels to get at least 120VDC.  

I'm focusing on the 30V panels mostly because that is the common variety that appears most abundant right now, with many going for only 30-40$ right now.  Maybe higher in Ukraine?  It appears that your MPPT's optimal voltage is around 240VDC, so you could go with up to 8 of those panels in series to make that voltage.  I prefer ground mounts, rather than putting panels on the roof, and the most I've built now is an array frame that can hold 6 residential panels.  That would be ~180V (1500W), which would work well for you.  If you build rotating mounts like mine, you can rotate it East in morning, and West in the afternoon, resulting in more total power.

I'd consider building the array frame like I've pic below, though with such a small battery, the extra watts won't get you much.  You really need a bigger battery to take advantage of extra solar.

10 мм

wire length 1.3 m

With a cross-section of 25mm2, it looks like it lays somewhere between 3 gauge, and 4 gauge, following American guidelines.  In the real-world, that looks like it is likely to handle 80A without getting too hot.  That works out to be about 4000W with a battery feeding the inverter at around 50V.  Most likely you are likely to get by as long as you never attempt to run the inverter flat out, at maximum wattage.  But, it's your call as how hot you are willing to push your wiring.

I can understand though that you are in a country at war right now, and you really have to make do with what you can find at the moment.  What I can suggest you do now is just attempt to run the unit supporting loads like the refrigerator, and lights, but not turn on any big-ticket items like an electric heater, or a microwave.  You can put a hand on the insulated part of the wire while running your loads to see just how hot it's actually getting.

You can control that a bit better by fusing it with a lower rating fuse, like 80A, even if you install it in front of a 150A breaker.  Some time in the future, when it becomes practical to upgrade your wiring, the 80A fuse can be dispensed with.

Have you started working on your solar input yet?  You haven't mentioned one word about panels yet?

Here is a good site for DC wire sizing: https://www.bluesea.com/support/articles/Circuit_Protection/1437/Part_1:_Choosing_the_Correct_Wire_Size_for_a_DC_Circuit

Remember the length of the circuit is both your negative and positive wires.

Michael Qulek wrote:With a cross-section of 25mm2, it looks like it lays somewhere between 3 gauge, and 4 gauge, following American guidelines.  In the real-world, that looks like it is likely to handle 80A without getting too hot.  That works out to be about 4000W with a battery feeding the inverter at around 50V.  Most likely you are likely to get by as long as you never attempt to run the inverter flat out, at maximum wattage.  But, it's your call as how hot you are willing to push your wiring.

I can understand though that you are in a country at war right now, and you really have to make do with what you can find at the moment.  What I can suggest you do now is just attempt to run the unit supporting loads like the refrigerator, and lights, but not turn on any big-ticket items like an electric heater, or a microwave.  You can put a hand on the insulated part of the wire while running your loads to see just how hot it's actually getting.

You can control that a bit better by fusing it with a lower rating fuse, like 80A, even if you install it in front of a 150A breaker.  Some time in the future, when it becomes practical to upgrade your wiring, the 80A fuse can be dispensed with.

Have you started working on your solar input yet?  You haven't mentioned one word about panels yet?

Tomorrow I will prepare the room for installing the inverter and battery, if the length of the wire is not enough for comfortable installation, I will put a 35 mm wire. If you think that this is critical, I will change the wire at the initial stage. I am sending a photo of the machine and fuse, there is an option to select a parameter. Should I put the machine on the + wire first, then the fuse? There are different opinions, the battery manufacturer recommends putting a 200 amp machine on the - wire. Others recommend putting a fuse on + and a two-pole machine on -, bifurcating the wire. They also do not recommend putting a fuse, citing the fact that the fuse is in the inverter itself. Regarding the panels, I have a problem, there is a shadow from the chimney pipe. Although now we have canceled the tax on the import of panels and I think that at the end of October you can buy panels very inexpensively.

manual

At this point, I would not worry too much about the shading.  With your sized battery bank, you'd have nowhere to put all the watts.  With your house drawing, what's the direction of the drawing?  I'll guess that down is South?    As discussed above, you might want to consider six panel strings of 30V residential panels, 180V in series, making 1500W per string.  Right now, it looks like you could fit a 6-panel string at the lowest point of the roof, and then a second 6-panel string right up at the ridgetop.  Assuming you can get 3.0 sunhours per day in December, that's 9000Wh of power, about double what the battery could accept even at zero charge.

If you want to add another 6-panel string towards the middle section, you could position the panels in two rows of three panels, placed on the far-right side of the roof.  That would at least allow you for some extra power at noon?

Lastly, you can utilize virtual tracking to add even more arrays.  Maybe another 6 panels facing due West, or 6 facing due East, depending on the orientation.  The advantage of virtual tracking is that you can get additional power in the early morning, or the late afternoon when the main South-facing array is not putting out much.   With your roof, I'm guessing that the roof to the far left of the pics is facing West?

By breaking up the panel strings in to shorter 6-panel units, you decrease the very negative effects of shading to maybe only one string at a time.

the inverter is installed and is used as a backup power supply now, the question of installing panels is on the table, they recommend installing 10 pcs LongiSolar LR54-HTH-430M considering the shading, there are three installation options

Based on the posted specs of the inverter I would say you go for the strings of 10 Panels. With these lower end all in one inverters they often have a "turn on" voltage for the charge controller higher then the low voltage cut out for the charge controller. So it says it can go down to 90 volts on the solar string but really needs 120-140 volts just to Wake up. If you were to go with 3 strings of 6 you would risk having them not turn on until they are in direct sun with any shading shutting down the string. I would say with your setup a string of 10 would be your best bet. You will have to play with the arrangement in terms of shading but you might end up with the east one producing all day despite the chimney and the west one loosing power in the afternoon due to the roof shading. That is a better option then trying to balance the two strings so they are equally mediocre.  Without doing a full workup of your site that is what i would recommend. You will have to watch out for high voltage in the string. On cold days when the sun first hits the panels the voltage they produce spikes and can exceed the high limit of the charge controller. The newer all in one charge controllers usually just overload and refuse it but some of the older ones burned out and died.  We usually design max string voltage to 1.25x the VOC of the solar panel x # of panels. That value should be bellow your max voltage of the string. Of course time of year, angle to sun, gauge of wire, length of wire from panels to charge controller all play a role.  
I am attaching a modified picture showing how I would do the strings. you will have to figure out the best wire path for each string and I killed three panels to give you 20 total. Based on experience the three closest to the intersecting roofs will have the biggest loss due to shading and snow.  In terms of safety replace the inverter wire when you can with a 0 or 00 gauge wire, I put a fusible link in the positive wire near the positive terminal for safety. Usually the breakers rated CE that can be mounted on a din rail even of chinese manufacture I find work well enough. I do not like the black square screwed on ones with the resetable temp overload as they are usually low voltage marine gear and unreliable. The din rail mounted fuse holders you showed are good. Make sure they are rated for the voltage you will be using. I wish you well as winter rolls in.
Cheers,  David Baillie

David Baillie wrote:Based on the posted specs of the inverter I would say you go for the strings of 10 Panels. With these lower end all in one inverters they often have a "turn on" voltage for the charge controller higher then the low voltage cut out for the charge controller. So it says it can go down to 90 volts on the solar string but really needs 120-140 volts just to Wake up. If you were to go with 3 strings of 6 you would risk having them not turn on until they are in direct sun with any shading shutting down the string. I would say with your setup a string of 10 would be your best bet. You will have to play with the arrangement in terms of shading but you might end up with the east one producing all day despite the chimney and the west one loosing power in the afternoon due to the roof shading. That is a better option then trying to balance the two strings so they are equally mediocre.  Without doing a full workup of your site that is what i would recommend. You will have to watch out for high voltage in the string. On cold days when the sun first hits the panels the voltage they produce spikes and can exceed the high limit of the charge controller. The newer all in one charge controllers usually just overload and refuse it but some of the older ones burned out and died.  We usually design max string voltage to 1.25x the VOC of the solar panel x # of panels. That value should be bellow your max voltage of the string. Of course time of year, angle to sun, gauge of wire, length of wire from panels to charge controller all play a role.  
I am attaching a modified picture showing how I would do the strings. you will have to figure out the best wire path for each string and I killed three panels to give you 20 total. Based on experience the three closest to the intersecting roofs will have the biggest loss due to shading and snow.  In terms of safety replace the inverter wire when you can with a 0 or 00 gauge wire, I put a fusible link in the positive wire near the positive terminal for safety. Usually the breakers rated CE that can be mounted on a din rail even of chinese manufacture I find work well enough. I do not like the black square screwed on ones with the resetable temp overload as they are usually low voltage marine gear and unreliable. The din rail mounted fuse holders you showed are good. Make sure they are rated for the voltage you will be using. I wish you well as winter rolls in.
Cheers,  David Baillie

. If I understand correctly, it is necessary to arrange 10 panels in 2 rows, which is indicated by fractional numbers in red and yellow?

bogdan smith wrote:

David Baillie wrote:Based on the posted specs of the inverter I would say you go for the strings of 10 Panels. With these lower end all in one inverters they often have a "turn on" voltage for the charge controller higher then the low voltage cut out for the charge controller. So it says it can go down to 90 volts on the solar string but really needs 120-140 volts just to Wake up. If you were to go with 3 strings of 6 you would risk having them not turn on until they are in direct sun with any shading shutting down the string. I would say with your setup a string of 10 would be your best bet. You will have to play with the arrangement in terms of shading but you might end up with the east one producing all day despite the chimney and the west one loosing power in the afternoon due to the roof shading. That is a better option then trying to balance the two strings so they are equally mediocre.  Without doing a full workup of your site that is what i would recommend. You will have to watch out for high voltage in the string. On cold days when the sun first hits the panels the voltage they produce spikes and can exceed the high limit of the charge controller. The newer all in one charge controllers usually just overload and refuse it but some of the older ones burned out and died.  We usually design max string voltage to 1.25x the VOC of the solar panel x # of panels. That value should be bellow your max voltage of the string. Of course time of year, angle to sun, gauge of wire, length of wire from panels to charge controller all play a role.  
I am attaching a modified picture showing how I would do the strings. you will have to figure out the best wire path for each string and I killed three panels to give you 20 total. Based on experience the three closest to the intersecting roofs will have the biggest loss due to shading and snow.  In terms of safety replace the inverter wire when you can with a 0 or 00 gauge wire, I put a fusible link in the positive wire near the positive terminal for safety. Usually the breakers rated CE that can be mounted on a din rail even of chinese manufacture I find work well enough. I do not like the black square screwed on ones with the resetable temp overload as they are usually low voltage marine gear and unreliable. The din rail mounted fuse holders you showed are good. Make sure they are rated for the voltage you will be using. I wish you well as winter rolls in.
Cheers,  David Baillie

. If I understand correctly, it is necessary to arrange 10 panels in 2 rows, which is indicated by fractional numbers in red and yellow?

Yes, the order will depend on you but you connect the panels positive to negative so there is only one positive and one negative per string. Looking it over I would order them differently than I did to minimize the return wire length. String 1 in red string two in yellow/orange. String one will be your main producer string two will fade away as the roof shades it.  Here we install a fancy electronic panel shut down system if its on a roof. If your inverter only has one solar input port you will need to combine the strings somehow. Usually you install a combiner with fuses in a weather proof box somewhere reachable but not easily reachable. I usually install the box at the 2 metre range off the ground. Understand all this is theoretical until you have your specification sheet for the solar panels themselves. The sheet will list working voltage of each panel and open circuit voltage of each. With that you calculate your string length. It might be better to go with a 9 panel string once you factor in 1.25 safety margin.
If it ends up being a 9 panel string here are two  possible alternates. I think the second one makes better use of wire but might have more shading... Its hard to fine tune this stuff as there are some non describable elements to how you wire a string for balance.
Cheers,  David

Please tell me if grounding is necessary for this system and if it is necessary, how to do it correctly?

10 solar panels
https://static.longi.com/Hi_MO_6_Explorer_LR_5_54_HTH_415_430_M_V03_DG_cd1618eade.pdf

bogdan smith wrote:10 solar panels
https://static.longi.com/Hi_MO_6_Explorer_LR_5_54_HTH_415_430_M_V03_DG_cd1618eade.pdf

Assuming you are using the 430 watt panels then you would be limited to strings of 8 panels each, 16 panels total. The math works out this way

39.13Vx1.25 safety margin X 8 panel string = 391.3 volts open circuit voltage which is within the inverter parameters
32.85volt working voltage X 8 = 262 Volts which is well within the middle range of the voltage curve
430watts per panel X 8 panels per string= 3440 watts per string X 2 strings=  6880 watts total . The inverter is rated at 6500 watts total but with heating, shading, efficiency losses you wont hit that.
If it was my system that is what I would install. You could do a single 9 panel string if you were going to install less panels but i would not install two strings of 9 panels each because if the sun hits them just right the cooling fan on the inverter will sound like a screeching cat and probably live a shortened life as you will be pushing the equipment to its absolute limit; never a good thing.

As to grounding the high voltage charge controllers in the inverter requires no grounding of the panels as the PV  circuit is not grounded. That is why its important to install an array disconnect before the inverter in case you need to work on the system. For grounding the array you usually run a ground wire to each rail on the roof down to your house ground wire and you ground the inverter ground terminal to the house ground as well.
Cheers,  David

Thank you, do I understand correctly that I can connect the ground wire from the panels to the general ground for the house, but for some reason they recommend making a separate ground for the panels or not making a ground for such a small station

bogdan smith wrote:Thank you, do I understand correctly that I can connect the ground wire from the panels to the general ground for the house, but for some reason they recommend making a separate ground for the panels or not making a ground for such a small station

NO that is not quite correct. The new high voltage solar charge controller built into your unit do not have a "ground" really. They have a negative input and a positive input which go into the pos and neg ports of the unit. On older lower voltage arrays the "negative" feed and the system negative were the same, not on these ones.  The only ground is from the solar array metal components to your house ground wire. Some places refer to this as "Earthing" or " bonding"  if that helps.  The only grounding you do to the inverters and feed from the solar array is connect the grounding terminal of the inverter to your home grounding wire preferably the large main one leading into the house.

Some say that solar panels are located on the roof of the house (in most cases this is the highest point of the household, therefore it attracts a potential discharge). Connecting this most dangerous (potentially) point to the common grounding - connecting all consumers of the household to objects of increased danger. Others say that one grounding circuit is needed so that there is no potential difference

bogdan smith wrote:Some say that solar panels are located on the roof of the house (in most cases this is the highest point of the household, therefore it attracts a potential discharge). Connecting this most dangerous (potentially) point to the common grounding - connecting all consumers of the household to objects of increased danger. Others say that one grounding circuit is needed so that there is no potential difference

That is old thinking based on the lower voltage charge controllers. You simply cannot connect the negative side of a high voltage array to ground they will not work. You do run the risk of conducting a lightning strike down to the ground cable with a metal assembly on the roof. The alternative is a lightning strike happens, it does not have a clear path to ground and it finds the best one it can; usually through the positive AND negative solar feed and shorts out everything it comes in contact with. I would suggest you install a whole home surge protector if you install a roof mounted array if lightning is an issue but really all homes should have them.