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MPP Solar LV5048 Bonding & Grounding question.

I definitely would not put a jumper between the input and output neutral lugs as this would create a potentially dangerous situation. The AC input feeds into the charge controller and the AC output comes from the inverter and there is no electrical connectivity between the two - other than grounding. By jumping the neutral lugs you connect half of the circuits. The problem is that when you shut off the input circuit breaker you expect both the load and neutral wires to be dead. By jumping the neutral lugs you create a situation where the input side neutral wire can still be carrying current even with the input circuit breaker shut off.

Personally, I put a small breaker box on the output side, bonded neutral to ground there and connected the ground bus bar to the GEC.
Thats not how electricity works though. The input neutral isn't a shock hazard because it returns to the source (the inverter). That's why you can open your electrical panel and grab hold of the neutral bar and it won't do anything to you. It doesn't want to go through you, it wants to get back to the source through the path of least resistance. Tying the neutral in/out together on these inverters is fine, I've been running that setup for nearly 2 years now. The reason you do it that way is to maintain your neutral/ground bond without having to tie them together later past the first point of disconnect. Bonding the neutral and ground after the inverter will lead to there being current flow on your ground, which in turn makes any metal (the inverter housing, the subpanel housing) a potential shock hazard.
 
Thats not how electricity works though. The input neutral isn't a shock hazard because it returns to the source (the inverter). That's why you can open your electrical panel and grab hold of the neutral bar and it won't do anything to you. It doesn't want to go through you, it wants to get back to the source through the path of least resistance. Tying the neutral in/out together on these inverters is fine, I've been running that setup for nearly 2 years now. The reason you do it that way is to maintain your neutral/ground bond without having to tie them together later past the first point of disconnect. Bonding the neutral and ground after the inverter will lead to there being current flow on your ground, which in turn makes any metal (the inverter housing, the subpanel housing) a potential shock hazard.
Sort of...
Electricity does NOT take the path of least resistance...
Electricity takes ALL paths available. If the chassis is energized, and you become part of the path, Electricity WILL flow through you.
If the voltage is sufficient to exceed the 100mA or so needed to shock, you will get shocked.
The reason you can touch the neutral bar/conductor is you aren't ALSO touching an energized point in the circuit.
Because the ground is not a path, it is a pathway...
 
Having a low resistance path is best for ocp... without a low resistance path, energized shorts remain energized.
And that's bad.
 
The reason you can touch the neutral bar/conductor is you aren't ALSO touching an energized point in the circuit.
Because the ground is not a path, it is a pathway...
True that it takes all available paths, but the point I was making was that you won't be shocked by a neutral alone by being connected to it in parallel which is what that other guy seemed to be alluding to. As long as the ground/neutral bond is maintained, you can't be shocked by a neutral (unless you get between it's path back to the source) because it's at ground voltage. If you get between the neutral and an energized part of the circuit then of course you will get shocked, but technically you'd be getting shocked by the energized part and not the other way around. Unless there is something I'm not seeing, I don't see how bonding neutral in and neutral out at the inverter could be a safety issue. The current is just going to go back to it's source depending on whether it's running on battery mode or grid mode.
 
unless you get between it's path back to the source) because it's at ground voltage.
Explain that. Scientifically.
Because I’m not convinced.

As a kid I got shocked by a drill with a three prong plug. I’ve been shocked a number of times changing kitchen faucets (back when they grounded to an incoming copper town/city waterline). And recently a member here had issues with +/- 60V between his RV and dirt.
As long as the ground/neutral bond is maintained, you can't be shocked by a neutral

Have you ever done a voltage drop test? You can be shocked from touching two different places on the same wire with the pressure of 120VAC
 
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Explain that. Scientifically.
Because I’m not convinced.

As a kid I got shocked by a drill with a three prong plug. I’ve been shocked a number of times changing kitchen faucets (back when they grounded to an incoming copper town/city waterline). And recently a member here had issues with +/- 60V between his RV and dirt.


Have you ever done a voltage drop test? You can be shocked from completinggbbg two different places on the same wire with the pressure of 120VAC
A drill with a metallic case, and a grounded plug not connected to a grounded outlet can become energized and allow a shock.

A damaged appliance not connected to a grounded outlet can energize the casing resulting in shock.

A sub panel connected to a main panel without a dedicated neutral can allow unbalanced current to flow on the grounding conductor resulting in a dangerous shock hazard on the grounding circuit, or the earth itself…
 
A drill with a metallic case, and a grounded plug not connected to a grounded outlet can become energized and allow a shock.”

Well somewhere something was sure wrong!

I was actually challenging the prior poster.

Safe electrical installations and safe work practices are there less to protect us from normal conditions, but to ensure safety when the unexpected abnormal conditions occur.

Since working on a kitchen faucet doesn’t (shouldn’t!) even involve electricity- getting sparks cutting a drain trap out or getting shocked disconnecting a faucet water supply clearly demonstrates that being “at ground potential” doesn’t guarantee not getting a shock.

Theoretically 120VAC with its conductors changing relative polarity 180* 60 times per second- if we assign the sine wave 360* per hertz for the purpose of example- is at ‘ground potential’ 60 times per second. Or we could say with the assigned 360* to the sine wave that 21,540 times per second a not-at-ground-potential condition exists that could shock you. (Of course a sine wave in reality is continuously variable.)
 
Well somewhere something was sure wrong!

I was actually challenging the prior poster.

Safe electrical installations and safe work practices are there less to protect us from normal conditions, but to ensure safety when the unexpected abnormal conditions occur.

Since working on a kitchen faucet doesn’t (shouldn’t!) even involve electricity- getting sparks cutting a drain trap out or getting shocked disconnecting a faucet water supply clearly demonstrates that being “at ground potential” doesn’t guarantee not getting a shock.

Theoretically 120VAC with its conductors changing relative polarity 180* 60 times per second- if we assign the sine wave 360* per hertz for the purpose of example- is at ‘ground potential’ 60 times per second. Or we could say with the assigned 360* to the sine wave that 21,540 times per second a not-at-ground-potential condition exists that could shock you. (Of course a sine wave in reality is continuously variable.)
The reason you got shocked off a sink faucet (I'm guessing) is because the house you were in had a compromised main neutral. That's one downside of the way we do things in the US. If your main neutral is compromised or lost, current will try to find its way back to the transformer any way it can. Normally that would mean it would go through the water line, to a neighbors house, in their panel, and up their neutral to the transformer. In this case you would be able to be shocked anytime you got between the returning current on the neutral, and ground. Don't believe me? If you live in the suburbs and share a transformer with a neighbor, go turn your main breaker off in your panel and put an amp clamp on your main water line. You shouldn't have any current on it but you will. The current is flowing from a neighbors house, through the water line, in your panel, and out your neutral wire. So if you cut that water line and get in between it, there's a potential to be shocked. I don't know if I can explain it any better than that. Just remember that it's not possible to be shocked by being in parallel with electricity, only in series. If you ever got shocked, it was because you gave the electricity an entry point and an exit point.
 
The reason you got shocked off a sink faucet (I'm guessing) is because the house you were in had a compromised main neutral. That's one downside of the way we do things in the US. If your main neutral is compromised or lost, current will try to find its way back to the transformer any way it can. Normally that would mean it would go through the water line, to a neighbors house, in their panel, and up their neutral to the transformer. In this case you would be able to be shocked anytime you got between the returning current on the neutral, and ground. Don't believe me? If you live in the suburbs and share a transformer with a neighbor, go turn your main breaker off in your panel and put an amp clamp on your main water line. You shouldn't have any current on it but you will. The current is flowing from a neighbors house, through the water line, in your panel, and out your neutral wire. So if you cut that water line and get in between it, there's a potential to be shocked. I don't know if I can explain it any better than that. Just remember that it's not possible to be shocked by being in parallel with electricity, only in series. If you ever got shocked, it was because you gave the electricity an entry point and an exit point.
Again, close.
It is completely possible to be shocked when in parallel with a circuit.
Series implies you are the only path in the circuit, and you can easily be parallel to a path in a circuit, and be shocked.

I have had many calls where showers or sinks were shocking my customers, and in every case, there was damaged circuits connecting poorly bonded piping. Usually from the main water line being replaced with pex, and still have metal plumbing grounded…
 
Again, close.
It is completely possible to be shocked when in parallel with a circuit.
Series implies you are the only path in the circuit, and you can easily be parallel to a path in a circuit, and be shocked.

I have had many calls where showers or sinks were shocking my customers, and in every case, there was damaged circuits connecting poorly bonded piping. Usually from the main water line being replaced with pex, and still have metal plumbing grounded…
Anytime you get in between a path for electricity to flow you are effectively in series with it. I guess technically you could consider that a parallel path, but for you to be actually shocked, the electricity has to go through you somehow, which means you are in series with that path. Maybe I'm not explaining my point well enough. Depending on how far you want to go with this, every branch circuit in your home could technically be considered in "parallel." What I'm saying is that if you simply touch a current carrying conductor, without giving it a second path to the source through some other body part, it's not possible to be shocked. You can grab hold of a hot wire and as long as you're not touching anything grounded and wearing good rubber boots, you won't be shocked. I've done it on accident many times. The old timers used to do it all the time.
 
I guess technically you could consider that a parallel path
gymnastic semantics
The old timers used to do it all the time.
The old timers that taught me were dangerous. Some of the newtimers too

There was a question the other day about a generator sitting on the lawn and a theoretical shock hazard from a camper. That doesn’t bother me as much or at all. But conditions that energize or could energize the bare/green? Bothers me a lot.

The sink drain pipe years ago that arced when I cut it: I don’t know if that was series or parallel but it was a path or the path for some fault we never found.

Another (not me this time) was either the washer or dryer would shock people when the phone rang.

It’s not what shouldn’t happen it’s about what could happen.
 
gymnastic semantics

The old timers that taught me were dangerous. Some of the newtimers too

There was a question the other day about a generator sitting on the lawn and a theoretical shock hazard from a camper. That doesn’t bother me as much or at all. But conditions that energize or could energize the bare/green? Bothers me a lot.

The sink drain pipe years ago that arced when I cut it: I don’t know if that was series or parallel but it was a path or the path for some fault we never found.

Another (not me this time) was either the washer or dryer would shock people when the phone rang.

It’s not what shouldn’t happen it’s about what could happen.
Just because you're not understanding it doesn't mean what I'm saying is wrong or I'm using some word salad. In order to get shocked, you have to give electricity an entrance point and an exit point. Period. Aka being in series with a path back to the source. That's taught in every Electrical Theory 101 class there is. Yes sometimes electricity does weird things, but it's not magic. It can only do what the laws of physics allows it to do.

This isn't even the point of the thread. The point was that jumping the neutral in and out on these inverters doesn't harm anything, doesn't cause a safety issue, and still maintains a neutral ground bond without putting current on the ground wire.
 
A lot of people think that just touching electricity alone is enough to shock you but it's not true. If you don't give it an exit point your potential simply rises to match whatever energized part you've come in contact with. It's the same reason birds don't get shocked when sitting on a telephone line, they're in parallel with the circuit rather than in between (series) it.
 
Just because you're not understanding it doesn't mean what I'm saying is wrong or I'm using some word salad
I’m sure I understand this completely
sometimes electricity does weird things, but it's not magic.
I’m not trying to be jerk but in reading I sound like one. Sorry

My point is merely sourced in the inverter bonding issue that constantly comes up. I am frustrated that equipment is often left to the user to discover it is or is not connected.
I recently contacted the mfgr of my little inverter because of this issue. While I eventually did receive a diagram regarding how to wire it in a manner they recommended that was not ambiguous, they had previously replied with three prior different answers that either had obvious issues or were not in comprehensive english. I did not relent until they affirmed how to bond.

This is a serious safety concern imho

In my case, I was instructed to make the N/G tie outside the inverter but electrically is the same as bonding internally. In essence it produces a length of potentially energized bare/green between the inverter and a GFCI.

In this thread, an MPP bonding question arose and you said,
Thats not how electricity works though. The input neutral isn't a shock hazard because it returns to the source (the inverter). That's why you can open your electrical panel and grab hold of the neutral bar and it won't do anything to you
…which is in my opinion a misguided statement that isn’t supportable and could lead people to do unsafe or even lethal things. It’s a thin blanket that can’t possibly cover all the things that could go wrong. Even N to G bonding- if the N is measured over a distance it is not unusual to have a voltage differential. One bad connection or other or a chaffed H somewhere and there’s a shock. I’ve even seen a couple houses with a dangling bare wire where the owner hit it with a mower or snowblower or something and there’s voltage between the wire and ground rod.

Blanket statements suggesting that grabbing the neutral bar in a panel is just not ok imho.

I’m not an electrician nor an EE but saying stuff that might lead to someone getting electrocuted to death is just a bit crazy. Do whatever you want but don’t lead people less knowledgeable than yourself to think they can do what you do and be safe.
 
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The reason you got shocked off a sink faucet (I'm guessing) is because the house you were in had a compromised main neutral. That's one downside of the way we do things in the US. If your main neutral is compromised or lost, current will try to find its way back to the transformer any way it can. Normally that would mean it would go through the water line, to a neighbors house, in their panel, and up their neutral to the transformer. In this case you would be able to be shocked anytime you got between the returning current on the neutral, and ground. Don't believe me? If you live in the suburbs and share a transformer with a neighbor, go turn your main breaker off in your panel and put an amp clamp on your main water line. You shouldn't have any current on it but you will. The current is flowing from a neighbors house, through the water line, in your panel, and out your neutral wire. So if you cut that water line and get in between it, there's a potential to be shocked. I don't know if I can explain it any better than that. Just remember that it's not possible to be shocked by being in parallel with electricity, only in series. If you ever got shocked, it was because you gave the electricity an entry point and an exit point.
Not snarky: What would an alternative be?

I’ve thought about this before and It seems you want to always give current a low resistance path that enough of it can take to reduce the hazard as low as possible. So it makes sense to give it a low resistance path while making everything conductive at the same potential - including the ground.
 
Not snarky: What would an alternative be?

I’ve thought about this before and It seems you want to always give current a low resistance path that enough of it can take to reduce the hazard as low as possible. So it makes sense to give it a low resistance path while making everything conductive at the same potential - including the ground.
There really is no better alternative that I know of. It's just a matter of which method is safest. Sure grounding everything together can potentially cause some bugs but it beats the alternative of having a floating neutral.
 
Sorry i havent been on in awhile, but i ended up ditching the bonding across the neutrals and run it as advised in the manual. Havent had issues with either but i don't like the idea of current going through the neutral into the output side.
 
Hello @SolarBro - thanks for this photo, this helped me a lot with figuring out my challenge. While trying to charge my Electric Vehicle completely off grid (shut off via a relay switch to avoid utility bypass) - no shore power, the car charger gives a ground fault. see attachment. However, when the inverter is tied to the grid with the AC input, there are no issues with the car charging. Any thoughts?

Screen Shot 2022-06-09 at 9.07.15 PM.png

If you are so inclined, here is what I am trying to accomplish: https://diysolarforum.com/threads/diy-battery-with-eg4-ll-and-lv6048.39923/

There is a lot of good discussions on that post.

Thanks!

John
 
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