Earth Grounding Solar Panels
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- เผยแพร่เมื่อ 7 มิ.ย. 2024
- I noticed that a lighting storm made my off grid system blink. Time to get the solar panels grounded. I am using 10awg bare wire to connect panels together. Then I test between the panels and the unistrut frame to make sure there is continuity. Lastly I use a sledge hammer to drive an 8 foot metal ground rod into the ground to attach the copper wire to.
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It's mainly luck that you got continuity between panels with those nuts/bolts and the jumper wires. The bolt/nut/washer are all acting on the anodized surfaces and you have a very small area of incidental contact within the bore of the hole and the threads of the bolt. You should use a self-tapping fastener to get good contact with the inner aluminum at least, or a fastener with features designed to penetrate anodized surfaces. Thermal cycling, vibrations from wind/rain/weather etc. may cause your current connections to fail without you knowing. Also, a t-post driver may be helpful for that second ground rod!
The small threaded screws I was using were the perfect size to dig into the frame of the solar panels. I think those worked out well. The issue might arise with the larger bolts used to mount to the unistrut.
@@LandtoHouse Would also recommend to spray those bolts, and the panel mounts, with some spray paint, either grey primer or aluminium silver, to provide protection from corrosion. Otherwise you will get corrosion as the copper and aluminium react, same for the unistrut rail bolts. The wire also needs to be 16 gauge or heavier, as it has to handle a potentially high current if there is a close discharge. Some strip aluminium would be best, large surface area, and you put a bend in it to allow flexing, and it makes a great bond.
For the other panels use regular 16 gauge romex, in a conduit, and simply put all 3 cores in parallel, so as to get high current capability. Also, ground rod dig down a little around it, and fill the hole half way with some rock salt, then cover again with soil ,so it will get a lower resistance to the ground. Will corrode the rod faster, but should easily last 10 years still.
@@SeanBZA- not a good idea to use romex in a conduit. Any water or humidity which gets in there can corrode the conductors & destroy insulation. Better to use wire rated for conduit.
Should use an 8 AWG ground cable and also need to run an 8 AWG ground cable from your new ground rod to your existing house ground.
Use paste when connecting Al to Copper!
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That was some hard work driving that rod, well done.
I used a T-Post driver on mine. lol
Subscribed!! Great video!! My wife and I are preparing to build our offgrid 6.5 kw PV System in Northern Nevada - it will be placed on top of a 40' sea container with equipment installed inside.
Nice job.
Thank you.
If you something gets struck by lightning it is 10 times more likely to be struck again. Some trees and boats are like lightning rods. That old tree behind a spring house or next to spring tapped the aquifer. Making it more likely to be struck too. A wet twig can be used as a spark plug wire. Remember to stay well grounded.
If your grounding rods are not bonded the lowest impedance path between your solar rod and your house rod is the solar wiring and inverter circuits. In the event you have lightning strike a nearby tree or anywhere on the ground there will be a difference in potential between your ground rods (earth is not the same potential everywhere), and if it is great enough, you will have a blown inverter. Ground rod systems can saturate and no longer carry additional current, so bonding them together increases the current that can be transmitted to ground and eliminates potential differences created by ground impedance.
I have a lot of grounding plus I use "Delta LA" surge arrestors thruout my system. There are specific models for D.C. and others for A.C. applications depending on voltages. One at the combiner for each array, another on each feed where they enter the building. I'm on the grid so another on that feed. Midnight Solar makes something similar but they are fancy tech and rather delicate (and expensive) whereas the Delta LA's are robust and can absorb multiple surges (and were less expensive years ago - haven't checked recently).
you can use a pole pounder to start the grounding rod.
Thanks for that,🙂
Great Job Seth! Keep up the hard work, there's this tool, there's always another tool, it's called a fence post driver, it's a tube with a welded on end and handles (we had a homemade one made out of steel pipe and an end welded on it, nothing fancy like handles) you raise it up and let the weight of the driver drive your fence post or what ever down into the ground. But hey, you don't need fences so why get one? Again, great job on a neat vid!
I use a steel post fence driver from the local co-op for ground rod driving.
If you have a hammer drill try using it some time. I welded a stripped socket to a cut off drill bit to keep the rod centered. It takes longer to set up than to drive the rod.
connecting copper wire to aluminum is not a good idea
Al and copper are dismissal metals, a tinned crimp lug will do the trick. Flat Aluminum bar is good for linking panels. Also remember to check your surge protection devices if your had lightening near by.
*Dissimilar
Do you have a rotary hammer? I have a cheap one from Harbor Freight. You can get an SDS (or SDS+) bit specifically to drive ground rods, but even without that the power tool is the way to go.
Suggest cad weld to ground rod for much better grounding. Lightning resistors at solar controller in and out.
Good job. All 42kWpv grounded at arrays. 18 Midnite Solar SPD’s.
I believe having to go back and do all this is no cost when an actual ground mount rail system bonds everything correctly because of the type of mounting hardware it uses. Just build a ground mount out of oilfield pipe and use the Ironridge mounting system. Ground one single rail to your rod and you have a fully bonded system, including the grounding of all the pipe.
I had never heard of that type pipe. I just installed another 3kw solar mount like this one and grounding took less than 1 hour. I like the wood mount system because it only cost $400 to mount and ground 12 panels.
Thanks for your information,I don't know what they earth solar panels to ground.
Panel surge and AC back feed are two reasons.
Good job prevention of static I would of made two grouds out of that rod chopped it in half lol
Is your inverter, charge controller ect grounded? Can you make a video on that
That's great work. I've watched numerous array install vids and I think this is the first I've seen on grounding.
What about for the appliances and everything your off grid system is powering? They would need a grounding cct as well right?
Thank you. Yes the electronics in the house have their own grounding rod. I went without a solar ground for 6 months and big storms caused power blinks. Now 6 months with ground I have had zero outages on the off grid system.
Can I use the 16mm deformed bar as grounding rod?
Lightening arresting is often misunderstood maybe its not intuitive as it might seem. You do not need to be struck by lightning to have a problem; during a storm high potentials and corona discharge flow from everything not just the highest object - the best path is the one it chooses but nearby conductors still see massive electric fields and can be damaged. Lightening rods to earth are NOT intended to carry a lightening strike to ground, they are intended to emit or collect charge which reduces the fields preventing lightening strikes which is might sound like its wrong but its not. Finally some inverters by design switch the whole PV array +/- several hundred volts every mains cycle which by capacitive coupling makes your panel frames lightly coupled to mains - if you stick a meter (high impedance) on a none grounded frame you see 50 - 150V of AC. Thats not really a problem but it can radiate interference to other stuff or a mains hum in audio which is annoying so better to ground them. The probably reason for the system blinking is that it lost ferquency lock due to a transient or the varistors or spark gaps quenched it and it needed to restart - thats by design but remember that such protection measures have a life, each time a MOX varistor activates some of its life is used and unfortunatley they tend to fail short circuit so it goes bang. That means anything you can do to prevent that is a good call. I've also noticed in very heavy deluges that static electricity can build up on panels and antenna, so leaking that away is good because if it builds too far it will cause breakdown of the PV PN junction by punching a hole in it.
does grounding of solar increase the rate of current supplied by the solar system
I think you made your panel system into a "lightning rod". But earth-grounding the panel frames is wise for personnel safety, and required per NEC. They allow using an existing metal post in the ground, instead of a separate grounding rod.
wait I guess I'm confused. When you installed the panels, did you not take the ground wire from the panels and run them to the inside, then ground the inside? I guess I'm confused why you're having to ground everything
You should consider a larger wire between the Unistrut instead of a smaller wire through the panel.
You need to considder where the current will flow through the grounding circuit. Right now you're current flow runs between two panels in the center of your array. That thin wire will be a fuse. It would be much safer for all of your panels if you ran your current flow through your Unistrut. This is why in data centers the devices are grounded to the cabinet and then the cabinets are attached to the grounding point. There we use 10GA minimum, and since this is all exposed to nature you are probably better off with a bare copper wire instead of an insulated one which will have water ingress at the exposed ends and connections unless its sealed better.
I was just about to write the same information.
You don't want current from lighting storms running in your panels, you want it to run in the unistruts instead. Ground each panel via wire to the unistrut and connect a large wire in between each unistrut
If lightning hits close to any of it it will all be toast, no mater what you do, except for not having it earth grounded at all. Not having it grounded may be the only chance to survive a near strike.
So shouldn't you check resistance to ground? That can vary largely due to soil type. I'm not sure what DC/solar ground resistance specs are so I'd like to hear from those in the know....Many here know household AC resistance to ground should be around 5 ohms.
I'm afraid that the the connection between the copper wire and the grounded Grounding Rod would be soon ineffective duo to corrosion?
Its possible. I have some grease that I can try if that does happen.
Should you also be connecting your inverters to the same ground rod to ensure that all components in the circuit are at the same potential?
Is there any code on how far the rod can be from the panels? I don't want to hit my panels when I am trying to drive the rod in the ground.
You will want the ground as close to the panels as you can get. But yes far enough away so that you dont hit the panels as you install the ground rod.
I really admire what you have been able to build and accomplish with your system. At the same time I would like to encourage you to study the grounding/lightning subject more carefully. You said your off grid system blinked during a lightning storm. Do you know why?
You said you you were "hoping that putting a ground rod in to earth ground the system is going to fix that issue". As a good friend of mine says.... "hope is not a plan". LOL
Let me explain to you what can and will happen if you get a close lightning strike to the ground. The voltage from the point of the strike dissipates outward through the ground. With DIFFERENCES of voltage potential at ground rods several feet apart being tens or hundreds of thousands of volts. This means that for a very split second the ground rod connected to your panels can be thousands of volts different than the ground rod hooked to your charger and inverter. For that split second the current through those devices connected to both rods can destroy them. This is what happens if it just strikes GROUND nearby. If it strikes the actual panels or inverter it's game over anyway whether there are two ground rods or not. You are just trying to handle a nearby strike as best you can.
There is a another part of nearby lightning strike problems that has nothing to do with striking the ground. Just striking in the air close enough to generate a tremendous electromagnetic pulse through the metal parts of your system. (and make your lights blink) This super electromagnetic wave will generate arc worthy voltages in those ungrounded objects. They need to be able to dissipate it into a single point of ground somewhere or they will jump to something causing fires of other damage to whatever is nearby including you. All equipment should be bonded together and connected to that single grounding point of the earth ground rod to dissipate that induced voltage quickly. I have my panels bonded together and an equipment grounding conductor wire running to the house with the pv wires and connected to the same ground rod as everything else. There are some that do put a ground rod at the panels but it is not normally connected to the panels. The panels are connected to a SPD device that connects the panels to the ground rod momentarily during a nearby air strike. Keep in mind this is charge that was generated on the metal panel frames being discharged into the ground at the panels for a millisecond or two. Unlike the first scenario where the charge is generated in the ground.
Many say to protect an array from a direct strike that you must put air terminals higher than the array that are grounded to divert the lightning to an easier path to ground. So you see, during a strike there are two different things to take care of. What is going on in the ground and what is going on above ground. There are times when multiple rods are in the ground but all hooked together with copper in the ground and there are times when there are two rods in the ground not bonded together ie.. One at the house and one at the garage but NO equipment between them to worry about. The possibilities are endless. Just study up on it and decide what works best for you.
At any rate I hope I have made you curious enough to learn more about it. I find it fascinating to learn about. I encourage you to look on youtube at some of Mike Holt's videos on grounding and such... be careful there are some videos out there that are completely wrong as well.
I wish you the best with your system!
👍
capped heavy iron pipe open one end slide over grounding rod . cant drop on head like a hammer when the shoulders burning
As someone who has driven plenty of ground rods in New England. I am laughing my butt off. 😂
Haha it was less than fun driving that through our NC rock clay soil.
Western Oregon - no rocks! Just clay. Makes it easy.
@@LandtoHouse Replaced ground rods recently at a house, biggest trouble was keeping them from disappearing into the ground. They went in with a pair of pliers as hammer. PVC pipe over the wire so that the garden service did not cut them again, like they had done before, as they trim with a weed wacker only.
I’ve heard great stories about grounding rods which deflected off rocks & hit the person sinking the rod, as the rod made a U Turn! 😅
thanks for sharing info...grear...done support by like & subscribed your channel...i'm also do DIY solar power but not great as you did..
Diy solar is the way to go! This has dropped my grid cost down by over 50%.
Pretty sure there will be continuity with 300 million volts going through it
Grounding wont do shit in a dc system without a gfci, you only add more area for the lightning to hit the panels.
Be careful of poison ivy next to that rod
You could have saved urself a LOT of work with a bottle of water. Stand up and jab the rod in the hole while pouring water down the rod every few secomds. You will push that rod in the ground by hand so easy you cant believe it. Dont believe me? Try it... just keep pumping it up and down.
I'm not an expert in the field but I've read/watched that most inverters feedbacking ac to pv. So be careful and ensure that you will not shock yourself by touch those panels!
Now that the panels are grounded I have not had an issue with the inverter shutting down during a lightning storm. It's definitely worth taking the time to ground.
Sorry I don't get the idea that PV panel frames need to be grounded. If they aren't mounted on a structure that is already grounding them by means of a metal frame then there is no ground reference to the PV frames. The DC circuit is isolated from the frame and only reference to ground is in the wiring connected to the controller PV tracker. By all means provide a lightening arrestor at the PV tracker location but otherwise installing an earth ground at the panels and turning them into a lightening spire just doesn't calculate? Lightening spires might be a good idea depending on the location and panel location but inviting lightening to strike the PV panels is not a good idea. Chances of the conductive path following only the frames to earth isn't likely. And will be very prone to blowing up panels and controllers as well.
Just saying............. Lightening makes up it's own rules as it goes and absolutely does not always follow the path of least resistance. The best defense is to keep it far far away and do nothing to attract it. Arrest it in your wiring everywhere possible and cross your fingers.
Equipment grounding is put in to facilitate the flow of electrical circuits and provide fault protection as well as personal safety against shorting. It isn't in place to protect against lightening. Whole different issue.
t post driver
Yes that would have made the job quicker.
It's funny how many youtubers make videos on fairly serious things without doing much research. Do your own do diligence.
Explain.