ksmithaz1
Solar / EV Junkie
Mike Holt / NEC Just watch some of his posts it will get clearer and clearer.
Complete guide for 48V using EG4 18k
- Thread starter Jdcarrol
- Start date
Quattrohead
Solar Wizard
You are grounded whether you like it or not ?
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Yup. I started to mention that earlier but decided not to add that complication to the conversation.
With that big metal post going down into the earth, there is an earth-ground connection to the racking that can't be avoided. I would still remove the ground rod, but it probably does not make a lot of difference.
What is not happening is a proper ground connection from the house to the racking system. To be to code, that needs to be added.
ksmithaz1
Solar / EV Junkie
He said the green wire is running all the way back to the house. That should do the trick if it is grounded at the same point as all the other stuff/
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Yes, it is going back to the house, but it is not going to the PV racking system or PV frames. This is what I see in the pictures
Any connection between the EGC from the house and the panel frames is incidental at best.
It needs to be more like this:
How the ground is connected to the rack and PV frames is going to depend on the racking system. Given the description of the installer, and how the ECG from the house was handled, it is unlikely anything was done to properly bond frames and racking together.
Grounding Made simpler - Part 3: Solar Panels
To get the paper, click on the orange button at the top of the screen. The subject of grounding is a complex, multifaceted subject, that is often treated as an after-thought but needs to be considered from the beginning of the design and build...
diysolarforum.com
@FilterGuy thanks for your detailed responses in this forum. Greatly appreciated insights
Thanks for the upgraded diagram! This is much simpler than the diagram in the EG4 18k manual (not to mention much cheaper to implement). You have eliminated the feeder taps, the feeder tap breaker, the two pole manual transfer switch. Is all of that stuff really unnecessary?
I assume the PV interactive system 2-pole fused disconnect shown in the diagram works as the AC surge protection near the inverter that you mentioned above?
I assume everybody knows what diagram in the manual I'm talking about, but I'll add it so you don't have to look it up.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Folks. One thing about the 'simpler' diagram is that I should have shown the AC disconnect as a fused disconnect.
Another point is that the EG4 diagram shows a transfer switch. The transfer switch is a handy addition that allows you to bypass the inverter for maintenance.
Oh, I see. The feeder taps are needed for the transfer switch. Ok, so just making sure I understand this correctly: In the EG4 diagram the only real redundancy is the Main Service breaker followed by the 2-pole fused disconnect. From an NEC perspective, I can simply remove the main service breaker and replace it with the 2-pole fused disconnect where I would also bond my neutral and ground. Since my electrical co-op requires a "lever" disconnect at the service entrance, this setup should comply. Is that correct?
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
There are many ways to skin the cat. Depending on the situation, you might or might not decide to use feeder taps. In a retrofit, the feeder taps may be the best way to set things up. However, a new installation would probably be done differently and not use feeder taps even with the transfer switch.
I am not sure I would say the Main service breaker and 2 pole fused disconnect are redundant. The feeder tap creates a 'y' in the circuit. Having an over-current device on each of the output legs is a good idea and I believe it is required by code.
That sounds correct. (I can't speak to the co-op requirements).
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
And one more thing:
In my diagram, I do not attempt to show the locations of the disconnects. However, depending on the situation and the local rules, there may need to be additional 'readily accessible' disconnects in order to meet the NEC and/or local code requirements.
In my diagram, I do not attempt to show the locations of the disconnects. However, depending on the situation and the local rules, there may need to be additional 'readily accessible' disconnects in order to meet the NEC and/or local code requirements.
ksmithaz1
Solar / EV Junkie
Ahh, apologies, the other/panel side, I was not reading/looking carefully . If the PV panels are mounted to steel/conductive framing which is welded/directly attached to the metal post the box is on, just pull the wire from the earth ground and/or clamp it with a self-tap and lug onto the frame/post and tie it in. I would not run a separate ground conductor to the panels. I don't see the benefit, and it creates another ground path. I think you should try to avoid multiple ground paths as much as possible. It also appears on closer inspection the box is plastic. Validate ground with a meter between the frame on the farthest panel and the post near the box. If the PV frames are for some odd reason not mounted directly to a metallic suface I would ground each to the closest point that reaches the frame/metal, then ground the post to the green wire inside the plastic box. The earth ground is pointless.
Just to fill in the gaps a bit more...
It's all metal on metal on metal. Every panel has metal mounting brackets to metal framing.
The grounding rod does have a self tapping screw into the panel mount framing, but the 6AWG green is only touching the frame metal if connected to the ground rod.
It is in a plastic junction box
If everyone is saying to just take the green wire directly to the framing and ditch the ground rod it wouldn't be that hard to get it there. Is that what you guys would recommend?
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
The NEC code is a bit more stringent than that. Just being all metal on metal is not enough. They want a certified connection between the frame and the ground.
Grounding Made simpler - Part 3: Solar Panels
To get the paper, click on the orange button at the top of the screen. The subject of grounding is a complex, multifaceted subject, that is often treated as an after-thought but needs to be considered from the beginning of the design and build...
diysolarforum.com
Well, back to the drawing board round 100. I'm just not going to get these SolarEdge optimizers working without the SE inverter, I don't want to get on the roof as a general goal.
I think I'm going to have to go the AC coupled route for my SolarEdge setup. I wrote it off initially to decrease points of failure and to keep my generator...but here I am full circle. Early in my research phase so bear with me. I also need to see if my SE7600H-US model can even handle frequency shifting...so much mixed information there. I will poke around in the settings more when I get home.
BUT, if I'm going the AC coupling route (and my SE inverter is capable) can it be as simple as this diagram?
Attachments
Hi, in this setup, the Grid terminal is just left untouch or something is connected there? If possible can you share a diagram like this where one can see how cables connected on the actual terminals? Thank you
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Sorry, I just noticed this question.
For a total off-grid setup with the 18Kpv, there are actually a few ways to wire the inverter Grid and Gen ports.
- If there is no generator, just leave the Grid terminals unconnected. The generator terminals can be used for a smart-load or for AC coupling. (I would think AC coupling would be a bit unusual for a completely off-grid system.)
- If there is a generator, there are two ways to go
- Leave the Grid Terminals empty and hook the generator to the Gen terminals
- Hook the generator to the grid terminals and set the system as a Micro-Grid. The generator terminals can be used for a smart-load or for AC coupling.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Here are diagrams showing the two different methods.
OPTION A
This one has the generator going to the Gen ports
OPTION B
This one has the generator going to the Grid ports. (The system MUST be set to Microgrid)
If there is no need for AC coupling or Smart load, I would use option A. I have no strong reason for that other than it is a bit more straightforward
Also notice that I added grounding to the batteries that I had previously left off.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
Since the original design, the owner has decided to use the new outdoor wall mount batteries instead. I will have him wire it this way:
A couple of things to note:
A couple of things to note:
- Since there are only two batteries I will have them each wired directly to the inverter. This eliminates the need for the parallel kit and it will provide a more even balance of the current.
- I am still deciding how to wire in the buck converter. (EG4 tells me they are working on providing connectors for this type of situation so I have not yet investigated it very deeply)
This might also be in line with the "code requirements" but in lieu of the 175A t-class fuses between the battery bank and the inverter does the internal battery breaker on the 18K serve as this?
I just installed virtually this same exact system and have yet to fire it up. Waiting on the electrician to finish installing all the outlets and fixtures
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Alright, I've had some time to finally sit down and figure out my "professionally installed" ground mount a bit further and I want to pick some more brains.Yes, it is going back to the house, but it is not going to the PV racking system or PV frames. This is what I see in the pictures
View attachment 163109
Any connection between the EGC from the house and the panel frames is incidental at best.
It needs to be more like this:
View attachment 163110
How the ground is connected to the rack and PV frames is going to depend on the racking system. Given the description of the installer, and how the ECG from the house was handled, it is unlikely anything was done to properly bond frames and racking together.
Grounding Made simpler - Part 3: Solar Panels
To get the paper, click on the orange button at the top of the screen. The subject of grounding is a complex, multifaceted subject, that is often treated as an after-thought but needs to be considered from the beginning of the design and build...
First off, here is the hardware they used:
Oddly enough, it does have grounding clamps! After I saw that I ran outside with my voltage tester, and sure enough, there is continuity between every panel, between the racking, and between the bare copper cable going to the ground rod at the array.
That being said, the only place the bare copper wire contacts the array is through a single screw/cable management bracket holding the bare copper wire to the leg of the ground mount (you can see pictures on a previous page here)....so how I'm getting continuity after 5 years of corrosion I'm not sure.
My plan is now to disconnect everything from the ground rod, and re-route that bare copper wire to the racking/cross bar, use a washer designed to penetrate into the metal to attach the bare copper wire there. Then the 6AWG ECG goes to my inverter and I avoid the "two ground rods at different locations" dilemma.
Does all of that seem like a good approach to handling this? Is there any specific place I need to attach the bare copper ground wire to...or do I not need to stress too much considering I'm getting continuity everywhere? Most of the ground mounts I've seen have a dedicated ground lug, and I don't have that here.
Seems like I don't have as much work to do as I thought I did...which makes me happy.
FilterGuy
Solar Engineering Consultant - EG4 and Consumers
sounds about right
EJansen
Solar Enthusiast
For anyone interested, here's an alternative install option that most people likely wouldn't do. My setup was a bit of an expensive experiment since I live in a neighborhood, with good power, and a whole house generator with ATS. Like the OP though, my intent was to just put a dent in my electric bill, since mine was creeping over $500/month. With my servers being pigs, and both AC units going along with the rest of the house loads, I've had 175Kwh days in the hotter months of July and August here in Virginia.
Recently I decided to upgrade to the 18K, since the 6500s wouldn't pass any sort of inspections where I live, and as I've posted before, I learned the hard way that they back feed power to the roof. Hopefully the 18K doesn't do that.
I also wanted to take advantage of the lower power consumption, integrated RSD that actually powers the inverter(s) down (and it looks like the battery bank too if using the new LLv2s per some recent Signature Solar videos that they posted on YouTube), and make it so it doesn't sound like aircraft is taking off in my basement when the loads are high or there's a lot of solar (the 6500 fans are quite loud). Here's a bit more about my setup:
The panel to the right next to the battery bank is a Sub-Panel from my Main, located in another room with limited space that's 25' or so away. That grid tied panel currently feeds the two EG4 6500s with double pole 60A breakers. The inverters feed the off-grid panel that's to the left, where I moved the larger loads that I was trying to offset. In this case, it's both AC units, my servers, some freezers, my sump pump, a 50A outlet in my garage for my welder / plasma cutter, and my gym. As far as Solar goes, I have 15 REC Alpha 400 panels on the back of my garage broken into two strings, and eight of the SolarEver 410w panels on the front of my garage in a third string.
I decided to upgrade to the 18K via the upgrade program, even though I didn't really "need" it, though it's not operational as of yet - that's what it looks like as of tonight. I'm still waiting on my T-Class fuses (though I went with 250A) since I never did integrate them into the existing setup and figured during the cutover process, it'd be a good time to do it. BTW, I was going to mount the T-Class fuses in the trough under the 18k, but perhaps it's better to be closer to the battery bank?
Also, there's something I didn't catch BEFORE buying the 18K that has me a bit hesitant to put it 'in production' and that's the Zero Export feature not really being a true Zero Export. My goal was to never back feed the grid (I don't have a net metering agreement), but there's another thread that I found yesterday, started by @FilterGuy (though, I haven't finished reading through the whole thread yet). saying that it's possible to back feed power to the grid. In my case, I believe it'd should be fine, since any back fed power should power the constant loads that are on my main panel. If anyone disagrees or has any other input, please let me know.
I've not had any issues with the 6500s back feeding to the grid, at least that I could see via my Emporia App from the CTs in the main panel. I thought the 6500s were grid assist only, and just had bypass mode, but maybe they had the same issue, and I wasn't aware of it?
Once I cut over to the 18K, I'll have a double pole 70A breaker from the sub panel feeding the grid input on the 18k, and the 18k Load output will feed the 'Off-Grid Panel', also with a double pole 70A breaker, though the diagrams in the EG4 Manual appear to be incorrect if you need to round up from 62.5A - see highlighted below (it's also on several other pages):
After I cutover to the 18K, I'm probably going to just leave the 6500s on the wall and have them ready to go, should there be some sort of issue with the 18K and I needed to 'fail back'.
If anyone see's something I'm missing or issues with the setup (other than the AC / DC conductors in the trough under the 6500s not being separated, though I think in the 2023 NEC it's allowed now), or if you have any questions, please let me know.
Recently I decided to upgrade to the 18K, since the 6500s wouldn't pass any sort of inspections where I live, and as I've posted before, I learned the hard way that they back feed power to the roof. Hopefully the 18K doesn't do that.
I also wanted to take advantage of the lower power consumption, integrated RSD that actually powers the inverter(s) down (and it looks like the battery bank too if using the new LLv2s per some recent Signature Solar videos that they posted on YouTube), and make it so it doesn't sound like aircraft is taking off in my basement when the loads are high or there's a lot of solar (the 6500 fans are quite loud). Here's a bit more about my setup:The panel to the right next to the battery bank is a Sub-Panel from my Main, located in another room with limited space that's 25' or so away. That grid tied panel currently feeds the two EG4 6500s with double pole 60A breakers. The inverters feed the off-grid panel that's to the left, where I moved the larger loads that I was trying to offset. In this case, it's both AC units, my servers, some freezers, my sump pump, a 50A outlet in my garage for my welder / plasma cutter, and my gym. As far as Solar goes, I have 15 REC Alpha 400 panels on the back of my garage broken into two strings, and eight of the SolarEver 410w panels on the front of my garage in a third string.
I decided to upgrade to the 18K via the upgrade program, even though I didn't really "need" it, though it's not operational as of yet - that's what it looks like as of tonight. I'm still waiting on my T-Class fuses (though I went with 250A) since I never did integrate them into the existing setup and figured during the cutover process, it'd be a good time to do it. BTW, I was going to mount the T-Class fuses in the trough under the 18k, but perhaps it's better to be closer to the battery bank?
Also, there's something I didn't catch BEFORE buying the 18K that has me a bit hesitant to put it 'in production' and that's the Zero Export feature not really being a true Zero Export. My goal was to never back feed the grid (I don't have a net metering agreement), but there's another thread that I found yesterday, started by @FilterGuy (though, I haven't finished reading through the whole thread yet). saying that it's possible to back feed power to the grid. In my case, I believe it'd should be fine, since any back fed power should power the constant loads that are on my main panel. If anyone disagrees or has any other input, please let me know.
I've not had any issues with the 6500s back feeding to the grid, at least that I could see via my Emporia App from the CTs in the main panel. I thought the 6500s were grid assist only, and just had bypass mode, but maybe they had the same issue, and I wasn't aware of it?
Once I cut over to the 18K, I'll have a double pole 70A breaker from the sub panel feeding the grid input on the 18k, and the 18k Load output will feed the 'Off-Grid Panel', also with a double pole 70A breaker, though the diagrams in the EG4 Manual appear to be incorrect if you need to round up from 62.5A - see highlighted below (it's also on several other pages):
After I cutover to the 18K, I'm probably going to just leave the 6500s on the wall and have them ready to go, should there be some sort of issue with the 18K and I needed to 'fail back'.
If anyone see's something I'm missing or issues with the setup (other than the AC / DC conductors in the trough under the 6500s not being separated, though I think in the 2023 NEC it's allowed now), or if you have any questions, please let me know.
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Quattrohead
Solar Wizard
Latest firmware and app gives you the option of putting it in genuine full off-grid mode, it will only attach to the grid when the batteries are in an oh shit state, even then it will not recharge the battery from grid unless you have a timer set up to do so. It just does a load pass through.
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