can i use grounding method

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http://www.fsec.ucf.edu/en/education/cont_ed/pv/handbook/Inspector_NEC.pdf
I looked over this document, but just want to find out the best way to ground this particular system.
I have attatched 3 options.. Attachment not found.Attachment not found.Attachment not found.

the basic scenario is this. There is a big ground mout system outside. the Home's main breaker panel is also outside on WEST side of home, HOwever all the breakers are located in a sub panel in the garage which is on opposite side East of home in garage.

NEC code I believ says that the DC grounding rod and the AC grounding rod need to be connected with 6 AWG bare copper wire.

I prefer option #1 because I only have to dig one trench. I can bury the DC ground wire in the trench and run conduit which carries the high voltage DC lines to the inverters in the garage. However the EAST side of home does NOT have a grounding rod. Is it OK to add a grounding rod and main bonding jumper to the subpanel? This subpanel does not have a main breaker, it just has lugs. I've never seen that done before, but why not?

Option #2 is the "standard way" Put the inverters outside and have them exposed to the elements. I'd like to avoid that. It's the same amount of work, one 100' long trench.

Option #3 is the least favorable. It requires two trenches West side trench has grounding wire, and East side trench would have conduit with high voltage wires.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: can i use grounding method

    The first one looks like it would have two separate grounding rods; one at the main panel and one at the sub panel. This would violate the "single point grounding" rule, as there would be a ground wire between the two breaker panels and thus you could have a ground loop situation.
  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
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    Re: can i use grounding method

    yes that is correct two seperate grounding rods.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: can i use grounding method
    yes that is correct two seperate grounding rods.

    Which, as far as I know, is not allowed except under certain circumstances (as in the ground rods are very far apart or they are electrically connected in an approved manner).
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: can i use grounding method

    how far is it to the pvs? if far enough away i'm thinking just go with wiles' way of doing it and just ground the pv arrays with a ground rod at the pv arrays and then run your required ground lead in with the + and - pv leads.

    your doing this is technically illegal, but i do this myself in your circumstance. if the arrays are close enough to the main ac ground rod then go ahead and trench the pv ground rod to the ac ground rod. the ground wire with the pvs is required to be there for code, but after the inspection i'd disconnect that wire both at the pvs and where it enters the building to prevent ground loops.
  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
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    Re: can i use grounding method

    Well the PV's are around 125 feet away from the home's east garage sub panel
    they are about the same 125 feet away from the home's west main load center panel.
    The distance between the two panels is around 45 feet.


    I'm not familiar with "wiles's way of doing it"
    I was going to put a grounding road at the PV panels and then "run your required ground lead in with the + and - pv leads"
    anyways, isn't that how it's supposed to be done? Are you saying a grounding rod is not required at a ground mount solar array? and when you "run your required ground lead in with the + and - pv leads" are you running the ground to the grounding bar in the sub panel?

    I do not mind the cost of the copper wire, it is just the labor of trenching 125 feet of ground wire. Does it really need to be trenched the whole way, or can I run it against the building behind some bushes for 80 or so feet?

    Which, as far as I know, is not allowed except under certain circumstances (as in the ground rods are very far apart or they are electrically connected in an approved manner).


    so if Option #1 is out, I guess Option #3 is the way to go. How deep does codes say the ground wire needs to be?

    Every book I've read seems to go with the mantra that the more grounding surface the better. So I naturally thought the more grouding rods the better. I'm guessing thie "ground loop" is some sort of electrical noise?
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: can i use grounding method

    Sorry but the rules are open to interpretation, especially by inspectors. :roll:

    What you'd have without the solar is three wires going back to the main with a ground. No need for a second ground at all, and of course no second neutral-ground bond in the sub box.
    The solar install requires a ground for the DC GFI ( :roll: ) circuitry. They want #6 AWG run to the main ground rod for this. If the line between the two breaker panels is sufficiently sized the DC grounding would connect to that; a 6 AWG run back to the main ground rod.

    Problem: the wire going in to the house from the PV grounding can become energized and make the ground wire 'hot' in respect to the 'real ground' and suddenly ground isn't ground anymore.

    Enter the second ground rod. Take any energizing and put it to Earth as near to the PV's as possible. Problem solved.

    New Problem: the regs say "single point ground" and any two ground rods must be connected together to act as one. The wire between the two comes back.

    I believe what Niel is suggesting (and I concur) is to put the rod in, tie it to the AC ground rod via #6 (preferably outside the house), then take it back out again once it is inspected. Technically this is not legal, but many of us think it is safer to keep the two grounds separate when there is that much distance involved. It's like your house's ground rod and your neighbour's.

    Also, this may not be what Niel was saying.

    (This is my interpretation only. Not an absolute guaranteed-to-pass authentic version of reality.)

    Personally I dislike the new DC grounding rules. They seem to have been designed for GT systems only, with no regard as to what happens when you have that second source of power known as batteries involved. Again, just my opinion.
  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
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    Re: can i use grounding method

    that makes sense, thanks for explaining it so well.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: can i use grounding method

    actually i am saying i am in favor of the trenched ground wire connecting the 2 ground rods. a ground rod is not required at the pvs by the nec which is (one of) wiles' ways. wiles and thus the nec require the ground lead to go from the pvs to the house and into the house to pass through all of your equipment and then it connects to ground at the main panel before it is able to pass to the outside again and into the ac ground rod. having both the trenched wire and the required ground wire with the pv wires creates 2 paths to the ac ground rod and this creates ground loops which is not desirable. what the inspector will see is the required ground wire going along with the pv + and - wires into the house. if you don't trench a wire then go with the ground lead entering the house and keep a ground rod present at the pvs as the distance between the rods is great enough to not worry about the 2 separate ground rods not being linked underground. think telephone poles as their grounds are not linked underground and those kinds of distances should not normally create any problems with the soil creating the loops. if you do trench a wire connecting the 2 rods then after inspection disconnect the ground lead with the pv wires to help prevent a path to ground that must pass through your dwelling and all of your equipment before reaching the ground rod. with wiles' way he doesn't care if he endangers your lives or property by allowing a path for lightning or emp to go through your home before reaching the ground.:grr the trenched wire bypasses the home and all of your equipment while also adding to the overall ground contact area making for a far better ground, but wiles requires a ground wire to go through your home from the pvs and i disagree strongly with this requirement.

    i hope i made what i'm saying clear enough as it is a difference of opinion between myself and wiles as to what is safe and most agree with me that the ground wire from the pvs is doubling as a lightning rod wire which wiles does not recognize as a problem being made to pass through a home.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: can i use grounding method
    niel wrote: »
    i hope i made what i'm saying clear enough as it is a difference of opinion between myself and wiles as to what is safe and most agree with me that the ground wire from the pvs is doubling as a lightning rod wire which wiles does not recognize as a problem being made to pass through a home.

    Here, here!
    This is exactly what I mean by the PV grounding may become energized. Potentially introducing several million Volts into the wiring of your home (all of which has insulation rated for only 600, so you can imagine how easily it can arc) is not a good idea.

    Niel's plan of connecting the ground rods outside the home is much, much safer. Whether or not it would satisfy the inspector is another issue.
  • Photowhit
    Photowhit Solar Expert Posts: 6,004 ✭✭✭✭✭
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    Re: can i use grounding method

    OK Now I'm confused (use to be a normal state, but I'm much better now:D)

    "...a ground rod is not required at the pvs by the nec which is wiles' way. wiles and thus the nec require the ground lead to go from the pvs to the house and into the house to pass through all of your equipment and then it connects ...)

    You can still have your system breakers outside in an electrical box, say and E-panel with AC breaker as your mail and our common connecting point ground outside in your E-Panel and run wiring to your inside panel, now a sub panel if currently on grid and disconnect the ground bond there? Correct?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: can i use grounding method

    Photowhit;

    If you mean move the grounding point to the exterior sub-panel (and have the neutral-ground bond there as well) so that any stray Voltage acting on the PV's would be Earthed at that point rather than traveling through the house, it should work. The integrity of the AC grounding would be maintained providing the wire between the two panels was sufficiently large (at least #6).

    However I'm not sure it would pass inspection. Someone might take a look at the main panel and see "no ground" and "no neutral-ground bond" and fail it, no matter if it were explained the ground and N-G bond existed elsewhere and was electrically sound. They can be funny like that.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
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    Re: can i use grounding method
    Photowhit wrote: »
    OK Now I'm confused (use to be a normal state, but I'm much better now:D)

    "...a ground rod is not required at the pvs by the nec which is wiles' way. wiles and thus the nec require the ground lead to go from the pvs to the house and into the house to pass through all of your equipment and then it connects ...)

    You can still have your system breakers outside in an electrical box, say and E-panel with AC breaker as your mail and our common connecting point ground outside in your E-Panel and run wiring to your inside panel, now a sub panel if currently on grid and disconnect the ground bond there? Correct?

    Interesting confusion. It is even bad over at Holt from time to time.

    1. The NEC calls for lots of ground rods in different places and under different circumstances. Under the NEC all of the ground rods related to one system must be bonded together. The wire that connects them has to meet various obscurely worded requirements, and is generically a bonding conductor, which connects two things together.
    2. The NEC calls for the neutral (which comes from POCO) to be bonded to the building ground system at exactly one place, namely at one of several locations in the vicinity of your main panel or the meter panel or the place where the service enters the house. Exactly where depends. This is accomplished by inserting the ground bonding screw or ground to neutral bonding jumper at that location.
    3. If there is a sub-panel in another building, you may put a ground rod there, and under some circumstances it must be bonded back to the rest of the grounding system. But the neutral may not connected to the ground system (or an isolated ground rod) at that point. Some solar installers and some inspectors fail to get this somehow.
    Since the PV inverter is connected to the POCO wires, it must be grounded (connected/bonded to the grounding system) but it cannot not have its neutral connected to ground locally.

    In this particular case (for which I would love to see a multiwire diagram), if you connect the POCO neutral to ground at the new outside box, yes you must remove the ground-to-neutral bond at the inside box.

    You are not allowed to bond the neutral at the PV system, and you must run a ground wire (Equipment Grounding Conductor) from the PV to the house system. The only argument that I see is what route that conductor is allowed or required to take. (And of course whether the DC/panel side should logically be grounded as the NEC requires.)

    Somebody else can address whether the Equipment Grounding Conductor is allowed to be the same conductor that joins the ground rods of one building to those of another. I have a headache.
    SMA SB 3000, old BP panels.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
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    Re: can i use grounding method
    Photowhit;

    If you mean move the grounding point to the exterior sub-panel (and have the neutral-ground bond there as well) Someone might take a look at the main panel and see "no ground" and "no neutral-ground bond" and fail it, no matter if it were explained the ground and N-G bond existed elsewhere and was electrically sound. They can be funny like that.

    I think that the point Niel and Photowit were making is that the exterior panel would then become the new Main Panel, with the original, inside, main panel becoming a sub-panel. That makes it clearer where the bonding jumper has to be, but leaves open the question of whether the existing wire which is used to connect the ground (not neutral) point of the old box to the new box is large enough.
    SMA SB 3000, old BP panels.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: can i use grounding method
    inetdog wrote: »
    You are not allowed to bond the neutral at the PV system, and you must run a ground wire (Equipment Grounding Conductor) from the PV to the house system. The only argument that I see is what route that conductor is allowed or required to take. (And of course whether the DC/panel side should logically be grounded as the NEC requires.)

    Technical point: PV doesn't have a "neutral". It has a (+) and (-) which must now both be ground-fault protected. This requires a grounding conductor which may/may not (depending on how you read those obscurely worded requirements) be the electrical safety ground for the GTI and AC systems. Some interpret it as being the same ground, other a separate (lightning) ground. I believe the former is true and the PV frame & mounts are connected to the separate lightning ground. But what do I know?
    Somebody else can address whether the Equipment Grounding Conductor is allowed to be the same conductor that joins the ground rods of one building to those of another. I have a headache.

    My opinion is no; equipment safety ground conductors can not be used also as grounding point connectors.
    This is why we have that problem with the two ground rods. If the ground of each panel is connected to the nearest Earth grounding point and then a conductor is run between the panels and another conductor between the rods you have a ground loop. Unless (and this is the tricky bit) you do as Niel suggest and use bare wire between the rods and bury it so the whole assembly becomes one large ground conductor.

    Or maybe I'm crazy.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
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    Re: can i use grounding method
    Technical point: PV doesn't have a "neutral". It has a (+) and (-) which must now both be ground-fault protected. This requires a grounding conductor which may/may not (depending on how you read those obscurely worded requirements) be the electrical safety ground for the GTI and AC systems. Some interpret it as being the same ground, other a separate (lightning) ground. I believe the former is true and the PV frame & mounts are connected to the separate lightning ground. But what do I know?


    Or maybe I'm crazy.

    Continuing the technical point: An ungrounded PV panel array does not have a neutral. Exactly right.
    But if (as is currently recommended by a stubborn few (OK, maybe many) who also have the ear of the NEC writers) you choose to ground either the + or the - conductor from the array, that becomes the neutral conductor for that configuration, and its wire color must be one which is allowed for a neutral wire. (When you get into three phase AC, I agree it is not that simple and you can have one phase conductor grounded without it becoming a neutral.)
    I was assuming the use of a grounded PV array, which is cheaper than putting in ground fault detection.
    SMA SB 3000, old BP panels.
  • Photowhit
    Photowhit Solar Expert Posts: 6,004 ✭✭✭✭✭
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    Re: can i use grounding method
    inetdog wrote: »
    I think that the point Niel and Photowit were making is that the exterior panel would then become the new Main Panel, with the original, inside, main panel becoming a sub-panel. That makes it clearer where the bonding jumper has to be, but leaves open the question of whether the existing wire which is used to connect the ground (not neutral) point of the old box to the new box is large enough.

    My calling it the mail rather than the main didn't help. In my case (with out hijacking the thread) the ground is at the pole currently and will be a shorter distance to the new grounding rod at the E-Panel outdoor electrical box w/ grounding rod next to it, so going for 200Amp service to less than 50, I've gotta be good.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: can i use grounding method
    inetdog wrote: »
    Continuing the technical point: An ungrounded PV panel array does not have a neutral. Exactly right.
    But if (as is currently recommended by a stubborn few (OK, maybe many) who also have the ear of the NEC writers) you choose to ground either the + or the - conductor from the array, that becomes the neutral conductor for that configuration, and its wire color must be one which is allowed for a neutral wire. (When you get into three phase AC, I agree it is not that simple and you can have one phase conductor grounded without it becoming a neutral.)
    I was assuming the use of a grounded PV array, which is cheaper than putting in ground fault detection.

    Cheaper, but not allowed. See? Regulations!
    As for the sub panel becoming the main panel, they wouldn't view it that way so long as the original main panel had utility feed and/or the main breaker. Regulations again.

    That's the problem; once the regulation are written what is sound from an engineering POV comes smack up against John Wile's "because I said so". :p
  • Photowhit
    Photowhit Solar Expert Posts: 6,004 ✭✭✭✭✭
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    Re: can i use grounding method
    Cheaper, but not allowed. See? Regulations!
    As for the sub panel becoming the main panel, they wouldn't view it that way so long as the original main panel had utility feed and/or the main breaker.

    I will be completely off grid, while I had intended to replace the 'master' breaker (I guess it would no longer be called a main?) I might go with a 4024PAE and leave the 200 amp breaker, with the 50 amp(?) at the Main I don't think that would be an issue.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
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    Re: can i use grounding method
    Cheaper, but not allowed. See? Regulations!
    As for the sub panel becoming the main panel, they wouldn't view it that way so long as the original main panel had utility feed and/or the main breaker. Regulations again.

    That's the problem; once the regulation are written what is sound from an engineering POV comes smack up against John Wile's "because I said so". :p

    You got me there. I meant to say ground detection. In an ungrounded array you have to be able to detect that the circuit is no longer floating. That is not the same as ground fault detection, and a ground fault circuit interrupter will not help you there since no current will flow through the accidental ground until a second fault occurs. It is common in the US on new installations to ground one side of the array and run the wires through a DC GFCI (regulations). But you do not at that point need "ground detectors".

    And in the case of the "sub-panel", there may not be any advantage to putting a second panel outside unless you do actually attach the utility feed there and convert the former service conductors running from the meter to the original panel to feeders from the new panel to the original panel, now a sub-panel. Both regulations and engineering. If the outside panel does not become the new Main panel, you are probably not allowed to bond the neutral to the ground there. You might be able to get away with bonding at the meter or somewhere else close but outside the new panel. I still have a headache from that one.
    SMA SB 3000, old BP panels.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: can i use grounding method
    Photowhit wrote: »
    I will be completely off grid, while I had intended to replace the 'master' breaker (I guess it would no longer be called a main?) I might go with a 4024PAE and leave the 200 amp breaker, with the 50 amp(?) at the Main I don't think that would be an issue.

    We really have left Rolland's original question behind, because now we're talking about a strictly off-grid set-up which would not have mains power at all. This is easily "reversible" because that 4024PAE is not going to kick out 200 Amps or anything close to it!
  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
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    Re: can i use grounding method

    so per the nec, a ground mount pv array has a 6 awg copper wire going back to the home where the GTI are and is grounded to the breaker panel, which has ground wires going throughout the entire home and all of those exit on the opposite side of this particular home throught the copper grounding rod?

    This just does not make much sense. So a lightening strike basically ensures your whole house's electrical system gets fried?Attachment not found.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: can i use grounding method
    so per the nec, a ground mount pv array has a 6 awg copper wire going back to the home where the GTI are and is grounded to the breaker panel, which has ground wires going throughout the entire home and all of those exit on the opposite side of this particular home throught the copper grounding rod?

    This just does not make much sense. So a lightening strike basically ensures your whole house's electrical system gets fried?Attachment not found.

    Yup. You got it.
    Hence the recommendation of 'stopping' the PV ground outside, one way or another.
  • rollandelliott
    rollandelliott Solar Expert Posts: 834 ✭✭
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    Re: can i use grounding method

    I would never do anything against code, but I have seen grounding wires come loose over time. That would be really convienient if lightening strikes the array.
  • Photowhit
    Photowhit Solar Expert Posts: 6,004 ✭✭✭✭✭
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    Re: can i use grounding method

    But Option #2 is still viable and wouldn't create issues since the ground is at the main, even if it is the least desirable...

    This keeps a single grounding rod and the current Main, I think most inverters are designed to handle the Heat and cold down pretty cool, a box built against the side of the house would help moderate temps...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: can i use grounding method
    I would never do anything against code, but I have seen grounding wires come loose over time. That would be really convienient if lightening strikes the array.

    If it actually strikes the array the whole thing's a goner anyway. The best you can ever hope for with lightning is to mitigate the problem of stray Voltage in the area around the strikes. The electrical safety ground circuitry is not meant for lightning strikes anyway. For that you need different equipment, like these: http://www.solar-electric.com/suprde.html

    That's the thing about grounding; it does absolutely nothing most of the time. But if you need it, it had better be right.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: can i use grounding method

    observe the drawing on page 107 and ignore the fact it is a gt inverter as that matters not being the pv requirements are the same for the ground lead. nobody is referring to a neutral, but observe the 3rd wire from the pvs shown in green. it is pv frame grounding!!!!!!!!!!!!!! this should not need to travel all the way back into the home as a potential path for lightning or emp, but the nec requires this wire to do just that. they do not allow you to just bypass entering the house by connecting directly underground to the ac main ground rod.
    http://www.nmsu.edu/~tdi/pdf-resources/CC103.pdf
    also you can see the nec does not require the ground rod at the pvs as it is listed as optional. i don't consider it optional if the pv ground lead is not able to go reasonably straight down to the ac ground rod. that wouldn't matter either as the nec requires this ground lead to go into the house along with the pv + and pv - leads and if you have a direct ground path connected this required one by the nec sets up a ground loop due to more than 1 path to ground, meaning one of these paths has to go. nobody is talking about grounding the - lead or creating a neutral so please don't confuse this as it is tough enough to explain it as it is.

    as with looping that ground conductor through the house it almost guarantees loss of property or life in the case of a direct strike or even near misses some times. going by the nec and still putting in a ground rod at the pvs does increase your survivability, but it will still provide a dangerous path into the house for some of that energy. now the underground connecting of the 2 ground rods with the elimination of that pv ground lead going into the house vastly increases your chances of survivability, but it is against the nec code.

    your best option if staying with the code is to go ahead with a ground rod at the pvs and still run the ground lead into the house. do understand that this does increase your risk for property damage and possibility injury and loss of life going by the nec code on this matter.
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
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    Re: can i use grounding method

    sorry guys, I now have a headache from reading the last dozen or so very excellent and explicit posts, all good for GT applications, BUT for an off-grid application as Photowhit has asked, WHAT SHOULD we off gridders adhere to for safety, especially when there is NO CODE enforcement, but rather personal safety?
     
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: can i use grounding method

    here you will still have an ac panel with breakers on it and a ground wire going to a ground rod from the ac panel. the only thing missing would be the tie to the grid really. the same precautions can be exercised here with such things like spds to further aid in protecting your equipment, but how the grounding is handled has a great deal to do with protection in the house. what i say would be when looking at the diagram i previously referenced to would be to eliminate the ground lead from the pvs to the house altogether and simply put that lead underground with bare #6 to the main ac breaker panel.

    now if you want to further try to stump me with a dc only panel then you failed as the ground wire and rod should still be there, but nothing traveling with the pv + and - wires as again a separate rod at the pvs would then connect with a bare #6 wire underground to the main ground rod at dc panel. simply put is to erase the green wire to the house as shown and place it below ground level on the drawing straight to the main rod and not the equipment in your house.

    now some confusion will appear here because a grounding wire is still needed in the house, but it will not start from outside the house. the first item the pv + and - goes to will start the ground going towards the breaker panel. if that first item in the house is a combiner with or without breakers the ground wire starts there. if it's the controller those wires go to first then that ground wire will start there. the internal grounding in the house is NOT eliminated as the only thing eliminated is the ground wire from the pvs coming into the house.

    you guys aren't the only ones with a headache as i've been trying to explain this for many years and it isn't always easy to get what i'm saying across.

    i just realized something. if you look at the drawing on that link that you see a bonding interconnection wire from 2 separate ground rods and a ground wire passing through all of the equipment too. guess what that is? if you said a ground loop then you win and this was from the guy making the nec rules for us to follow.:cry: the only time that would be valid to do that is if it was a #6 bare copper wire interconnecting those ground rods underground.
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
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    Re: can i use grounding method

    thanks Niel, it was mostly the house ground that was bothering me. 3 SPDs as per MN wiring for an E-panel, + + + etc.

    I plan on a PV ground and was thinking that it would be more effective if the AC main panel grounding wire came from the house, out to the PV ground vs from the PV to the house then to ground, as you identified is a problem.

    Thid has been a good investigation of the grounding issue/rules. A possible Sticky?
     
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: can i use grounding method

    if enough of you want it stuck then we can sticky it. reread the previous post by me westbranch as i kept fine tuning my wording.