Quattrohead
Solar Wizard
I have in the past and will again very soon, lived with and tested various scenarios, so I fully understand thanks.
Currently have panels scattered all around the back yard in our temp home whilst I build our final home.
Series or Parallel
- Thread starter jimmy747
- Start date
Currently have panels scattered all around the back yard in our temp home whilst I build our final home.
Quattrohead
Solar Wizard
You should never ever find voltage on your panel frames, if you do you have a faulty panel that is leaking.
Grounding the frame does not fix the fault, find it.
Hedges
I See Electromagnetic Fields!
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- Mar 28, 2020
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Correct there should be no "leakage", galvanic conducted path.
But there is capacitance from PV leads to frame.
Some of the AIO drive AC superimposed on PV+/PV-
That is the fault we would like to fix, but it is out of our hands.
The AC voltage couples through panel to frames, and has shocked people.
Grounding the frames (which would also maintain human safety in case of a fault in the panels) carries away the milliamp level 60Vrms or whatever these poorly designed inverters deliver through the panels.
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Please be careful when you contradict a post.
You are making the thread difficult for the OP to understand.
My statement MUST be adhered to.
IF there is a home setup that solar panels have a ground bonding requirement, the ground bonding system MUST be connected to the house grounding system.
If you do not have a house grounding system, the inverter MUST be connected to the same grounding system as the panels are.
There is ALWAYS the potential for any metal parts connected above earth potential to gather current. If the current is not connected to the SAME point your body connects to, YOUR BODY can be the path of current...
This is bad.
Quattrohead
Solar Wizard
We agree just in different ways.
So all cars, airplanes etc should be grounded with 8AWG ???
Quattrohead
Solar Wizard
Like this is not done hundreds of times each month.
No one killed the Growatt transformer threads....they should have been.
There is the NEC way to make things safe....full of loops and contradictions, the common sense way and the stupid "lights up, job done" way.
If they are electrified and energy potential is being generated by the car, yes.
#6awg for unprotected ground though.
Quattrohead
Solar Wizard
Optional extra for your Tesla, #6AWG lol.
I'm being petty, I'll shut up.
I'm being petty, I'll shut up.
SOMETIMES the hold button will save max..
Sir, let me see if I understand this correctly. You stated "IF there is a home setup that solar panels have a ground bonding requirement, the ground bonding system MUST be connected to the house grounding system." My house which is connected to the grid has a working ground. So. I should ground my panels, inverter, batteries to the same ground as my house i.e. my main electrical panel (green wire bus terminal) correct? Thank you.
Partimewages
Solar Addict
There are lots of NEC codes. Here's a link for some insight from a couple years ago. https://www.iaei.org/page/2021-01-grounding-and-bonding-solar-photovoltaic-systems
Sometimes the terms bonding/grounding/earthing are used interchangeably. This is confusing (especially when viewed from different countries/languages). Bonding typically refers to joining one of the current carrying conductors with the 'ground'. Within this context, 'ground' is a reference plane, typically at 0V, and which serves as a means to carry a fault current. When the fault current occurs, a fault current detection device is used to switch the current off. This prevents that metal parts become energized.
For this reason, all metal parts are also connected to this reference plane, and thus are at the same potential. Any live conductor that comes free (e.g. through vibration) and tries to energize a metal part (e.g. an enclosure) introduces a fault and will thus trigger the fault detection device.
If the metal part would not be 'grounded', the part could become energized and can lead to a dangerous situation. Now bonding a current carrying conductor to this ground plane (i.e., your Neutral at the fuse box) makes it so that a fault current can actually flow: if it is not, and e.g. the live conductor connects to the metal enclosure, there still isn't a way for the current to flow back to the source unless the Neutral is connected to the ground plane.
For this reason, metal parts (solar panel frames, inverter housings, etc) should always be connected to this ground plane. However bonding one of the current carrying conductors to ground is not always required: with solar panels, if you don't, you get what is called a floating installation - and these have been the default in Europe since forever. The requirement with doing this however is that you have to have a double pole breaker (interrupting both + and - of the panels) and (in some countries like Australia) a dedicated fault detection device or is part of the inverter it is connected to. For the US specifically:
"An ungrounded PV array, as permitted, per 690.41(A)(4), is where neither of the dc conductors from the array is grounded, which is the most popular of all the array configurations in the U.S. today. In such a configuration, it is especially important to provide ground-fault protection because there would, otherwise, be no way of detecting a ground-fault in the array, which underscores the importance of the GFPD’s functions in a solar PV system." - you can find that in the link @Partimewages posted.
Also note that just adding a grounding rod is usually not enough, because the impedance gets to high (soil is not a good conductor) and in that case a connection has to be made from the ground rod to the main earth connection. This is somewhat different in a TT network with European style whole system ground fault detection devices which tend to detect small current leaks, and don't rely on a breaker with higher current going through the fault link, but that's for another discussion...
TL/DR: metal cases and solar frames/arrays are always connected to ground. Current carrying conductors are sometimes bonded to ground - check your local requirements and ask a professional in your area.
For this reason, all metal parts are also connected to this reference plane, and thus are at the same potential. Any live conductor that comes free (e.g. through vibration) and tries to energize a metal part (e.g. an enclosure) introduces a fault and will thus trigger the fault detection device.
If the metal part would not be 'grounded', the part could become energized and can lead to a dangerous situation. Now bonding a current carrying conductor to this ground plane (i.e., your Neutral at the fuse box) makes it so that a fault current can actually flow: if it is not, and e.g. the live conductor connects to the metal enclosure, there still isn't a way for the current to flow back to the source unless the Neutral is connected to the ground plane.
For this reason, metal parts (solar panel frames, inverter housings, etc) should always be connected to this ground plane. However bonding one of the current carrying conductors to ground is not always required: with solar panels, if you don't, you get what is called a floating installation - and these have been the default in Europe since forever. The requirement with doing this however is that you have to have a double pole breaker (interrupting both + and - of the panels) and (in some countries like Australia) a dedicated fault detection device or is part of the inverter it is connected to. For the US specifically:
"An ungrounded PV array, as permitted, per 690.41(A)(4), is where neither of the dc conductors from the array is grounded, which is the most popular of all the array configurations in the U.S. today. In such a configuration, it is especially important to provide ground-fault protection because there would, otherwise, be no way of detecting a ground-fault in the array, which underscores the importance of the GFPD’s functions in a solar PV system." - you can find that in the link @Partimewages posted.
Also note that just adding a grounding rod is usually not enough, because the impedance gets to high (soil is not a good conductor) and in that case a connection has to be made from the ground rod to the main earth connection. This is somewhat different in a TT network with European style whole system ground fault detection devices which tend to detect small current leaks, and don't rely on a breaker with higher current going through the fault link, but that's for another discussion...
TL/DR: metal cases and solar frames/arrays are always connected to ground. Current carrying conductors are sometimes bonded to ground - check your local requirements and ask a professional in your area.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 20,682
All the grounds should connect together.
But I suggest you daisy chain from PV panel frames to inverter to house ground, rather than wiring directly from PV panel frames to house ground. I wouldn't want disconnection of a wire between breaker panel and inverter to allow voltage to appear on the panel frames. or between ground wires an electrician is working on - he might not expect backfeed through grounding system.
[Edit - simply means keep the ground wire with the power-carrying wires.
I think it is OK to also branch out with a redundant ground wire back to house ground (make a ground loop). With my metallic conduit for AC and DC going to multiple inverters, that happens due to PV ground wires grounding to combiner box or switch. But they also have continuity through from PV frame to inverters.]
But I suggest you daisy chain from PV panel frames to inverter to house ground, rather than wiring directly from PV panel frames to house ground. I wouldn't want disconnection of a wire between breaker panel and inverter to allow voltage to appear on the panel frames. or between ground wires an electrician is working on - he might not expect backfeed through grounding system.
[Edit - simply means keep the ground wire with the power-carrying wires.
I think it is OK to also branch out with a redundant ground wire back to house ground (make a ground loop). With my metallic conduit for AC and DC going to multiple inverters, that happens due to PV ground wires grounding to combiner box or switch. But they also have continuity through from PV frame to inverters.]
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Thank you for the link. I will definitely read it.
Thank you upnorthandpersonal I now understand the difference between grounding and bounding. In Aruba maybe regulations are different so
I will definitely reach out.
Thank you Hedges. I will change my diagram. Also I am going to look in this forum at the section "System Schematics" for wiring a similar system. I beleive in no need to reinvent the wheel! I understand most of what you guys wrote but a diagram is very helpful to me.
Well maybe the following info might help someone. Today I had an unofficial visit from someone working at the electrical company. Basically he confirmed to connect everything to the same ground. BUT. He pointed out that average 30 years old house were grounded to the water line. Over time, pipes have been replace with plastic which obviously is not a conductor. The best and safer solution is to plant a new ground 6 feet deep near my house. I will ground all my solar equipment to that ground and ground as well my main panel to that ground. Right now the panel has a small copper wire serving as a ground. So who knows if it is really properly grounded. So that is where I am today. The hybrid inverter arrives tomorrow. It is exciting. Let me know if you guys have different opinions. Thank you.
Partimewages
Solar Addict
Water pipe thing was more like 40+ years ago at least around here. It was supposed to be in conjunction with ground rod also but since plastic pipe is used then the outdoor grounding system has taken its place.
