So what should it read (or not read) if the unit is bonding N/G?
MPP Solar LV1012 N-G Bond
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timselectric
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120v from hot to ground, verifies N/G bond.
Bud Martin
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timselectric
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That works too. As long as you verify 120v between hot and neutral, first.
12VoltInstalls
life passes by too quickly to not live in freedom
I’m interested in understanding why?
There is no circuit to the dirt. With the exception of lightning (which could be handled at the array frames) what does a ground rod accomplish?
Job trailers, RVs, boats- none have a ground rod nor present any danger. In my case, for example, the RV entrance panel is not bonded N-G. The 1012LV (as affirmed by posters above) when grid is connected establishes G via the grid panel connected outlet. When I disconnect from grid (unplugging or turning the switch I installed off) the 1012LV closes the N-G internally thereby properly and safely establishing the safety ground.
In a purely off-grid scenario, however, the 1012LV is the ‘source of power’ and is the N-G bond always. Add a generator to the mix and you would not ‘open’ N-G at generator but rather allow the 1012LV to switch over when gen is running (so generator remains ‘safe’ to use for other purposes if desired).
Unless there is something I’m missing I do not believe that safety is served any added benefit with a ground rod and further can envision a potential ground loop situation while generator is running and connected to the LV1012.
Not intending to be argumentative- just want to understand why a ground rod would be desirable in an off grid install.
Thanks Timselectric for your reply.
"How are you going to make the connection between the generator and inverter input?"
I plan to simply strip the end from an 12g extension cord and secure the bare wires to the AC Input L-N-G terminals. When needed, I'll plug the prong end into the generator's duplex receptacle.
"does your generator have a N/G bonded output?"
No it does not. The Neutral is Floating.
"How are you going to make the connection between the generator and inverter input?"
I plan to simply strip the end from an 12g extension cord and secure the bare wires to the AC Input L-N-G terminals. When needed, I'll plug the prong end into the generator's duplex receptacle.
"does your generator have a N/G bonded output?"
No it does not. The Neutral is Floating.
timselectric
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Sorry, one more question.
Does this generator have a GFCI output?
timselectric
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I'll get back to you, shortly.
Busy morning.
timselectric
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This is so that if a circuits hot finds its way to earth, it will trip the breaker. Rather than possibly hurting, or killing someone.
Example:
An extension cord, or appliance cord has a nick in the insulation. And, the 120v hot wire is exposed. This cord is laying on the earth, after a rain. This will make the earth live. With the earth connected to the grounding system (through the installed ground rod), the breaker will trip. (Because the grounding system is bonded to the neutral)
timselectric
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A lot of people believe that power wants to go to ground. (Not true)
Power wants to go back to the source.
Breakers and fuses are designed to do two things.
Open the circuit if there's a short. (No load or near no load connection, on a circuit)
Open a circuit if too much current is flowing though the circuit.
Power wants to go back to the source.
Breakers and fuses are designed to do two things.
Open the circuit if there's a short. (No load or near no load connection, on a circuit)
Open a circuit if too much current is flowing though the circuit.
timselectric
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Ok
So, when using the generator there will be no N/G bond. I would recommend using a GFCI pigtail.
For additional safety, when using the generator.
timselectric
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Also, I would not recommend adding a ground rod at the solar array. But, if you feel the need to do so. It must be connected to the grounding system.
NEC doesn't require any auxiliary ground rods. But, doesn't say that you can't. (I really wish that it did)
But, it does say that any auxiliary ground rod must be connected to the existing grounding system.
NEC doesn't require any auxiliary ground rods. But, doesn't say that you can't. (I really wish that it did)
But, it does say that any auxiliary ground rod must be connected to the existing grounding system.
timselectric
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I also recommend surge arrestors at the solar array.
And if the array requires more than 50' of wiring ran outside, surge arrestors at both ends.
And if the array requires more than 50' of wiring ran outside, surge arrestors at both ends.
12VoltInstalls
life passes by too quickly to not live in freedom
With the dirt(earth) connected to the grounding system it creates a circuit that wouldn’t exist if the ground rod wasn’t there. There is no ‘stray voltage differential’ because the dirt has no interaction with the Source Of Power in an offgrid system.
NEC 250.134 allows grounding at the array per NFPA 780 - which wants as short of a run as possible for grounding of the frames. NEC 690 is only for gridtie systems.
But NFPA does…and:
I thought NFPA says the panel array grounding rod should not connect to an off-grid residential electrical system so it doesn’t encourage lightning to enter the dwelling as it is not part of the electrical circuit AND there’s the ground loop issue again.
Again, not being argumentative, but I want to understand if I’m wrong. Even if I’m right. I’m not seeing how dirt not in the circuit needs to be part of the circuit for mitigation of any safety concerns.
The 1012LV is the ground, and dirt irrelevant to that offgrid
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Diysolar123
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absoletey positively this....
you must measure because calling the manufacturer does not always result in the right answer in todays "special" tech support world...
you can also easily do this by using a receptacle tester such as:
just plug it and switch to battery...real simple; and you should probably have one these types of things in your toolkit anyway ;-)
ahh, good thought. I do have one of those testers and did use it previously. However, can't remember if I did the test on battery AND if I tested with the AC input disconnected. I'll check again this weekend
timselectric
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The grounding system is a protection system, that provides a path back to the source for any fault current that ends up where it shouldn't be. Since things happen beyond our control. That we wouldn't be aware of, until it causes damage, or bodily injury. It's better to cover all possible situations. And connect anything potentially conductive to the grounding system. (Electrical enclosures, metal structures, water and gas piping, earth, and anything else you find on the property) I'm not talking about lighting protection. Lighting protection should be a completely separate system. I don't want to connect my solar array to a ground rod, in close proximity. This will attract lighting to the solar panels. That's something that I want to avoid. And before anyone says that it doesn't "attract" lighting. I'm not saying that it causes lighting to strike. I'm saying that if lighting is going to strike in the vicinity, I don't want
The solar panels to be the path of least resistance. (Which is what electricity will always try to find)
Lighting protection should be placed around what it's supposed to protect. And not be electrically connected to what it's supposed to be protecting.
Anyway.........
That's my opinion on the subject.
Do with it what you will.
12VoltInstalls
life passes by too quickly to not live in freedom
I appreciate that. Appreciate your time.
Again, not trying to be a jerk, I appreciate your insight and that you allowed for opinion here. As we know many (most; nearly all) aspects of household electricity are not open to differences of opinion but rather are either correct- or not.
So with no angst or judgement I am ok to disagree. I personally would NOT earth/dirt ground a holistically off-grid system as I see no point in introducing that circuit. Caveat: I believe there is an NEC reference that some jurisdictions use to require offgrid systems have a ground rod, but my foggy memory is ringing a bell that a mike holt video debunked that requirement. While I don’t think it was called out as inherently dangerous it was called unnecessary with a small potential for problems
12VoltInstalls
life passes by too quickly to not live in freedom
So, you got your answers- so did I
To recap:
And now you know it’s not a good idea.
you do not have to and it’s my opinion that it’s better not to. Panel array should have a rod from the frames.
It completes the circuit within- although under generator power (or grid) it disconnects that bond - as it should.
With your generator ‘open’ you should think about that. I was going write something but it’s a rabbit hole I couldn’t do in a sentence or two so I deleted it.
In battery/solar- within itself
On generator or grid, at the generator or grid entrance panel
