What a clean and efficient installation at the unit - beautiful! How did you connect the unit’s two DC wires (assuming you clipped off the MC4 connectors) to your 12 AWG THHN whip wires underneath the electrical access cover? Wire nuts or something else?
Help me Install 3 EG4 Mini Split Solar Heat Pumps
- Thread starter MrM1
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MrM1
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Maybe it's OK ... Maybe it's not, but I left their MC4 connectors on and add my own to my 12 awg stranded THHN wire. Then just tucked them back inside the unit where they were when shipped.
I did not use the included MC4 connectors (in the bag) that would (supposedly) have matched and been of the same brand as the ones that came installed. But from what I have seen of any Chinese manufacturing they use what they have today. So who knows if what they used in the units matched what is in the bags.
In the EG4 AC/DC Manual it says use same brand. But I have never read that anywhere before, and if that were true then when you install solar panels you should cut off the factory ends and install new ones matched sets, which would void the panels probably.
So I don't know if it was a good thing or a bad thing but that's what I did.
Roger - thanks for elaborating. I will probably follow your lead on the internal DC connection approach and then broadly when it comes to the final cosmetic touches. Really like the clean look of just the one flexible conduit running from the unit to the DC and AC breakers combo in the small box.
MrM1
I'm Here, But I'm Not All There
Ok, back up on the roof. Running new screws in the metal b4 the arrays get installed.
Whew, This is a multi day project. About 1000 screws
Whew, This is a multi day project. About 1000 screws
jjfmetal123
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good idea, I did the same thing!
RDuke
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Wow, 1000 screws, that is a lot a work. I am trying to visualize that. Maybe post a pic ?
Anyhow, I have my own projects keeping me really busy (spelled exhausted today), but I did want to follow up with you regarding the array bonding and grounding. While I am new to working with solar, I have done a fair amount with power over the years. If I am reading how you are grounding the array, I would be a little concerned over lightning. My state is on 2020 code and I don't have my book I ordered yet, but it is my understanding it is ok to drive a ground rod for the array framing and bonding it to the house grounding system, but you may not want to do it that way. I am not being critical by any means, just thinking out loud. I was watching one of Mike Holt's NEC youtube videos from 9 years ago called "Solar PV Grounding Electrode System" (34 min long), and he makes some pretty good arguments about why you MAY not want to do that even though it is allowed by the code at the time the video was made. Code may change, but the physics of what he is saying stays the same.
Of course I am not trying to stir the pot here being a new member and all. But I thought I would mention that years ago, the cable company wanted to drive their own ground rod on the far side of my house when it was being installed. I told them no, you have to attach it to my power ground and run it 22 ft under my concrete driveway. Needless to say he was not happy, and when he called his boss I used reference to the NEC to get it done correctly. Since then 3 trees have been hit within 150 ft of my house, and I am the only house without major damage. One took out my microwave but it hit right next to the power lines and I suspect that is how it got in. I have a very large "Current Technology" whole house SPD now for that. The neighbors with separate ground rods for the cable had major damage as the nearby strike went in one rod, through the house wiring, and out the power grounding system as the current left the point of the strike.
I am not too far away from you being in coastal GA. We both definitely have to pay attention to lightning risks. Just wondering what your take is regarding the potential issue. (attached pics of my whole house SPD - yep it is big, weighs about 100 lbs. haha)
RDuke
Anyhow, I have my own projects keeping me really busy (spelled exhausted today), but I did want to follow up with you regarding the array bonding and grounding. While I am new to working with solar, I have done a fair amount with power over the years. If I am reading how you are grounding the array, I would be a little concerned over lightning. My state is on 2020 code and I don't have my book I ordered yet, but it is my understanding it is ok to drive a ground rod for the array framing and bonding it to the house grounding system, but you may not want to do it that way. I am not being critical by any means, just thinking out loud. I was watching one of Mike Holt's NEC youtube videos from 9 years ago called "Solar PV Grounding Electrode System" (34 min long), and he makes some pretty good arguments about why you MAY not want to do that even though it is allowed by the code at the time the video was made. Code may change, but the physics of what he is saying stays the same.
Of course I am not trying to stir the pot here being a new member and all. But I thought I would mention that years ago, the cable company wanted to drive their own ground rod on the far side of my house when it was being installed. I told them no, you have to attach it to my power ground and run it 22 ft under my concrete driveway. Needless to say he was not happy, and when he called his boss I used reference to the NEC to get it done correctly. Since then 3 trees have been hit within 150 ft of my house, and I am the only house without major damage. One took out my microwave but it hit right next to the power lines and I suspect that is how it got in. I have a very large "Current Technology" whole house SPD now for that. The neighbors with separate ground rods for the cable had major damage as the nearby strike went in one rod, through the house wiring, and out the power grounding system as the current left the point of the strike.
I am not too far away from you being in coastal GA. We both definitely have to pay attention to lightning risks. Just wondering what your take is regarding the potential issue. (attached pics of my whole house SPD - yep it is big, weighs about 100 lbs. haha)
RDuke
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SilverbackMP
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Wow, 100lbs. I just have a MidNite solar SPD on the AC side (one per panel) and on every incoming wire set on the DC side. Wonder if I need more?
RDuke
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Mine is definitely overkill and very expensive - way beyond what most would install. But I got a good deal on this one and the nice thing about this model is it can take massive surges repeatedly and never take damage to the MOVs. It uses large semiconductors for the long surges which would toast MOVs. It only uses the MOVs for the short fast spikes. I met the guy who designed these in Texas years ago, Barry Epstein back before he sold the company. I was super impressed with both him and his product, smart guy.
RDuke
RDuke
SilverbackMP
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I’m not afraid of either overkill or expensive (within reason). Off grid with a ton of money wrapped up in my system (which will likely grow), plus some smaller servers, and woodworking and welding equipment and maybe some milling stuff in the future.
I would probably need multiple units for multiple buildings though.
MrM1
I'm Here, But I'm Not All There
Looking at the Mike Holt videos for several years, I know he has tried to get the NEC code to see it differently, The main idea as Understand what Mike advocates for is that you do not what it going thru house and all the electrical system to get to ground, but you do want it part of the main whole house grounding system, not a separate grounding system. Thus I route the array grounds to their own rod, but that rod is tied to the whole house grounding system thru the earth via 6 gauge wire.
My understanding is that you can have multi rods as long as they are tied together. This does not constitue 2 separate grounding systems nor 2 places of potential difference.
My understanding is that you can have multi rods as long as they are tied together. This does not constitue 2 separate grounding systems nor 2 places of potential difference.
SilverbackMP
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This whole thing does my head in. Especially when you have multiple buildings on the same system. We went with one per building plus one at the ground mounts. Almost all of my runs are in oversized conduit so I could add if needed. Sometimes even have an extra empty run of conduit also buried in the same trench for future expansion. Plus one to two runs of smaller stuff for fiber.
timselectric
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Multiple ground rods are considered auxiliary electrodes. While not required, they are still currently allowed (but not recommended).
They must be connected together for electrical safety. But connecting them together creates an equipment Hazzard.
Because it lessons the resistance over distance. Compared to the earth itself.
Which is why they aren't recommended.
When lightning strikes it creates a gradient pulse across the earth. This pulse dissipates over distance from the resistance in the earth. But the EGC that ties the auxiliary electrodes to your grounding system has less resistance. So it allows the pulse to cover more distance.
By installing auxiliary electrodes. You are increasing your chances of equipment damage. Because you are essentially reaching out to a larger area. So more of the strikes are within reach of your system.
MrM1
I'm Here, But I'm Not All There
Well I'm not installed yet. So tie them all together - Array, Equipment grounding conductors (EGC), etc - and run them all to the main panel ground busbar and out to the main ground via the GEC bypassing the aux ground ? My earlier understanding was you did not what this. But you also did not want to separate systems.
I'm open to doing it different. I am at the beginning stages of install
MrM1
I'm Here, But I'm Not All There
timselectric
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This is what I would do.
How far apart are the two ground rods?
Distance between is what you want to avoid. Since if installed, they must be connected together.
Personally I avoid auxiliary electrodes, whenever possible.
All grounding must be tied together. How this is done is up to the installer.
SilverbackMP
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What say you for multiple buildings? One per (sub)panel or just one total?
timselectric
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If it's required by the inspector to add one at separate buildings. Then you must to pass inspection.
If not, don't.
Either way you are required to run an EGC back to the existing grounding system.
My inspector required it for my detached garage. I disconnected it after inspection.
NEC is always evolving. It will catch up, eventually.
RDuke
New Member
Thanks for the discussion. I know it can get tricky depending on the installation - like what SilverbackMP is asking. It will probably be a while before I can install my panels as I need a new roof first, so in the mean time I will just run the 12k off the grid. Mine is supposed to arrive on Tuesday am I am worried that if they use a full size 18 wheeler, they will have problems in my neighborhood with delivery because we have huge live oak trees everywhere.
By the way your installation job is really neat looking and I would not have even thought of the valence idea, very nice.
RDuke
By the way your installation job is really neat looking and I would not have even thought of the valence idea, very nice.
RDuke
SilverbackMP
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I don’t have an inspector. My semi-retired electrician is my inspector lol.
My power shed, my mom’s house, my shop, two other outbuildings, and other future projects (second workshop, greenhouse, my house) are on/will be on an interconnected off grid set up. Probably will remain all SMA to keep it KISS as much as possible and redundant for spares.
SilverbackMP
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The good thing about rural areas in some “flyover states?”
No inspections.
The bad thing?
No inspections.
If I’m jacking something up, sometimes there’s no one readily available to ask a question to.
No inspections.
The bad thing?
No inspections.
If I’m jacking something up, sometimes there’s no one readily available to ask a question to.
MrM1
I'm Here, But I'm Not All There
But you are not required to be inspected , or you're just doing it without a permit
SilverbackMP
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No inspections, no permits required except septic (two page application, $50 fee), no statewide NEC adoption, no zoning, no hoops, no BS.
By Gawd Missoura. Everything Texas imagines itself to be.
MrM1
I'm Here, But I'm Not All There
For the house main panel I have 2 grounding electrodes (rods) 6+ feet apart.
Then There is 20 ft between the array ground and the house ground system. These are connected along the ground via #6
MrM1
I'm Here, But I'm Not All There
I wish I lived there
RDuke
New Member
Yea I am not looking forward to having my solar setup inspected. In 2021 I had GA Power move my service underground. I paid a local electric company to do most of the work. I asked them drive 2 new 10 ft rods for the ground at the new service disconnect panel, and I bonded my copper water pipe inside that panel where the NG bond is. The inspector wanted me to remove the water pipe #6 solid and attach it to my intersystem bonding bridge by running it outside my house. What??? So I paid for a copy of the code just to show the guy that was not right, and he never came back. My electrician said yea , he just signed off on it anyhow. Of course that was after I paid another 100 bucks for the 2017 code. We are on 2020 now. Granted it would have worked, but nowhere does it say that is how to use the intersystem bonding bridge. I was not impressed. So I am dreading how the same guy may inspect a more complicated installation.
RDuke
RDuke
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