I'm a retired electrical engineer, and I can tell you with certainty the loops don't matter. By the way, the loop you are pointing to has both wires (plus and minus) paired together so their magnetic fields would mostly cancel; that means those loops have a lot less inductance than you think. But it doesn't matter. The whole DC string is one big loop anyway, so looping the cable just increases inductance slightly. And that's not a bad thing. A bit of added inductance just means a little more spark on the disconnect contacts when you open it.
Your videos were one of the primary sources of encouragement that gave me the confidence I could install my own 37 panel system!! Everything was delivered last week and we are about halfway through installing mounts and rails. Thanks for all the great videos!
Grounding is not for lightening, it won't do much against a strike, It's for transient over voltages. You're also missing distinction between bonding and grounding. Bonding creates a uniform voltage plane. Grounding is primarily to provide a low resistance path to trip the breaker.
@@altuber99_athlete I'm well aware but most people call the Equipment grounding conductor and Grounding electrode conductor... just ground. Outside electricians or EE's few realize they serve a different purpose and how they function to do so.
@@steven7650 Oh, I thought you didn’t know, since you said “Grounding is primarily to provide a low resistance path to trip the breaker”, which is incorrect. Bonding (connecting the neutral bus bar and ground bus bar together at the main panel) is done for that. What grounding (connecting the neutral/ground bus bars of the main panel to the planet Earth ground) does is allow excess charges (from lightning and electrostatic) to be mitigated. Grounding + bonding establishes the neutral-to-ground voltage to zero or near zero volts at all normally non-current-carrying metallic pieces. Or that’s how I look at it.
@@altuber99_athlete Understandable as most just use ground the way I remarked which as you correctly point out is incorrect or at least incomplete. Bonding is more for creating an equipotential plane around an object which may become energized, think pool, hot tub or such. The neutral to earth bond at the service sets the reference though it's very minimal because North American Utilities use a multipoint ground system already. As you said it's more for directing excess current to the earth in case of strikes.
Respectfully I seriously and absolutely disagree. The Grounding (earthing) intended purpose by design is NOT to provide a 'low resistance path to trip the breaker' as stated! Earth resistance is unpredictable - how can it be a part of an engineering design to operate in a fault? Point being - NEVER depend on 'dirt' to provide a low resistance path to the source.
Another thing about zip ties... you want to use relatively wide zip ties to prevent chaffing from cutting through the cable over time. Wide zip ties tend to be larger than the ones I see in the video. I know it seems like a waste of plastic, but it makes a big difference. I've taken apart old solar systems (15+ years old) where the zip ties had done more damage to the wiring than just leaving it loose would have.
I wish people would stop saying that grounding panels is for lighting protection, it really isn't. Lightening protection is a completely different structure isolated from the structure you are trying to protect. If you think a 10 or 6mm² cable is going to protect fromm 1000's of volts and amps it won't. Directly grounding a structure actually makes it more attractive to Lightening. Good information on the DC coiling
Thanks! The pipes may appear small in the video, but they are a heavy wall pipe. We get 60mph+ winds here fairly regularly and the rack holds steady with no issues.
It is not the inductance which is generally the problem but the heat dissipation, if you bundle wires heat cannot be dissipated efficiently and.you have to derate the wire.
Hi Dave, love the content. It would be interesting to give Jordan another project and have him take a look at voltage loss from panels to the inverter. I suspect your wiring is throwing a bit of heat and your system's a bit leaky.
Thanks! Great Idea! I did a calculation on the losses from the array to the inverter before I installed the system. That showed the loss would be very small, however, I have never checked the actual situation. I'll have him do that. : )
@@ProjectsWithDave Don't listen to Ed Stiver. Jesus man I'm an electrical engineer. I design power systems for a living and I would worry one second over that coiled wire. It is amazing the amount of BS people worry about. Not one person, such as Ed, could calculate the "leaky"-ness of your system. You can spend 3 weeks analyzing stupid shit that amounts to no significant difference. When you know what you're doing you don't need a calculator to verify it.
Interesting - assuming we are talking about leakage-to-ground, I will be happy to check that for you using a simple Fluke 1587 with no calculations required! No big deal and no cost. Since you have so much knowledge, it might be good to submit a paper letting IEEE know that calculations are worthless if you really understand electrical engineering concepts.
Actually, even Jordan's statements are overstated. For DC - yes not an issue. Even for AC, though, from what I can see you have both wires (ie. supply and return path) coiled up together and lying right next to each other. The fields largely cancel out and so your actual inductance will be much lower - likely negligible. Similar structures are used in electronic components routinely - for example the bifilar windings of wirewound resistors which are specifically designed to reduce the inductance of the resistor to negligible values or common-mode chokes which have negligible impedance to your incoming AC power, but noticeable impedance to common-mode voltages picked up via EMR and other noise sources.
The problem with grounding is when lighting strikes the wet ground it travels up your grounds and takes out your fret board on the inverter. I learned that the hard way. I cut all my grounds and only use battery grounding. Haven't had that problem again for 28 yrs.
How will the lightning energy coming up FROM the earth into your ground rod - and then into your equipment physically destroy the equipment? If your theory is valid, then a 3,000,000 volt lightning strike hitting an airplane would completely destroy it in a massive ball of fire. In comparison, a bird landing on a high-voltage power line should be incinerated.
You can always connect your strings using Cross-Connection method, nip one slip one. Advantage is also get same lengths on your + and - wires and neater cabling. Not all makes has longer cables eg Longi panels
Dave, I notice that a 9.36KW unboundsolar kit with SolarEdge optimizers costs around 14K as of today. Your system costs were closer to 10.6K for your "kit". Why the difference? Did costs go up or did you save money clipping?
The kit posted online includes racking for roof mounting, but I used the Ready Rack ground rack. You can see my cost breakdown by part here: ruclips.net/video/PNTO83FvaL4/видео.html
Great video Dave!! thanks - Question for the future.. have you washed the panels yet? Should you avoid city water and use distilled? Any certain brushes to use?
Thanks! Great question! I deliberately did not manually wash the panels since install two years ago. I want to understand if cleaning is a significant consideration for ground vs roof installations. I have been watching build up of dust and bird poop and seeing how much of it the rain takes care of. So far, not cleaning them hasn't been a noticeable impact to performance. I'll keep your suggestion in mind for a future video once I have determined the best approach.
I clean mine twice a year .. and bird poo etc as needed.. and possibly clean anyway.. as I think the dirt or pollution can be abrasive and acidic .. and I want them to be as efficient as possible in cloudy weather.
@@shrujanamsyama9940 Over the decades I've had various types of panel, I've even used a surface treatment which does help.. Just like a greenhouse, car or home windows they all get a build up of dirt that the rain, even hail or snow doesn't remove...
Hi and huge Like from Estonia! Everything is clear and well explained! Only one question about strings. Why not to make "left" and "right" U-s and connecting box in center? Then You dont need extra cables.
Question: you state that you run your DC leads “all the way back to the house”. Is there a preference in running DC lines (like you) a long distance or a converted AC line a long distance? I’m setting mine up now.
You can get the cost information in this video: ruclips.net/video/PNTO83FvaL4/видео.html The supplier is in the description, I used Ready Rack. The description also has time stamps so you can jump right to the racking portion.
The fact that you have to coil the wires means there is unnecessary length which does add resistance. It must not be enough for concern because no one has ever mentioned it.
@@ProjectsWithDave He asked about the "grounding" clips between panels. Your link is for "cable management" not grounding. I'd like to know also, thanks! Those clips that you put the multi-meter on look like they would be cheaper than the solid copper wire 4 awg that I'm using to connect my twelve panels to each other using the older clip with twist bolt that you also showed.
Find More information for this project and others on my website: projectswithdave.com Other related solar videos that may be helpful: Full Solar System Install: ruclips.net/video/_xA6qOwnYbM/видео.html 3 Solar Panel Wiring Issues Answered: ruclips.net/video/i7vHEHB3a-M/видео.html Check out the first year performance results here: ruclips.net/video/BatTeSq05rU/видео.html See the total system cost here: ruclips.net/video/PNTO83FvaL4/видео.html And How to size your solar system here: ruclips.net/video/rbFnZqA0GCI/видео.html 4 Things to Know About Solar in the Snow: ruclips.net/video/vY3PufzPUnI/видео.html Ground Vs Roof Mount Solar: ruclips.net/video/w-iS_8e7n60/видео.html How to Get A Permit For Your Solar System: ruclips.net/video/imiEYDHLG4A/видео.html How to Crimp MC4 Connectors: ruclips.net/video/oH3LqTu4B8E/видео.html
How deep should the grounding rod be in the ground. What determines the depth? The ones at the home/hardware stores are 8 feet long. Why 8? Or 10 or 6?
I'm considering increasing my array size. I believe I can still get a reasonable payback period for some increase in size. As for batteries, the technology needs to improve quite a bit from a cost perspective before it can be justified. It is possible that in the near future electric cars can provide the dual purpose of a household battery backup. Things are changing quickly in the battery area so I think I will wait on that for now. Thanks!
@@ProjectsWithDave Lithium hasn't changed in decades LOL. And you wouldn't want your pos electric car to go to the junkyard even faster using it as a power source.
Doesn't having two earth/ground points - solar array and then main panel - create a really dangerous potential for a ground loop? Wouldn't you need to bond the two ground rods?
You can't really avoid a ground connection at the array. The metal posts are buried several feet into the ground and the frame is connected to the grounding system. The code in my area required me to connect my array to my house ground using a #6 copper conductor.
Great video. I too have a solar system. I was hoping you could clarify grounding for me. Did you ground the negative conductor from your panels? If yes grounding makes sense to protect people from damaged panels as they would be completing the circuit to ground. If you didn't ground the negative there is no circuit to ground so there is no risk to people. Grounding for lightning strikes. Why do we want to encourage lightning to go through the panel frames? Massive DC amps will cause considerable damage. Would it be safer to have separate lightning rods at the highest point of you system that are wired to your grounding rods completely separate from the panels?
Sorry, I'm not an expert on lightening strikes and bonding to be able to give you the benefits and risks of lightening rods. However, I don't think I would want to intentionally attract lightening to the area. I did not connect the negative conductor of the PV panels to ground. However, if the frames are not bonded to the grounding system they could become energized by a positive conductor that was damaged and touched an isolated frame. As long as the frame is bonded to the grounding system any short will be directed to ground rather than through you.
@@ProjectsWithDave additionally if the panel is damaged and the positive is now connected to ground through the frame, If you touch the negative conductor you will get shocked
Grounding the Negative of a properly designed DC power system is fine but it may include one concern - a Ground Fault (the DC+ shorted to Ground) of sufficient magnitude will open the source Fuse/Breaker. As a result the problem then becomes finding the fault itself so you can fix it and get your power back on! Good luck unless you are a professional! Bottom-line, floating the DC Negative is not a problem at all if properly designed, installed, and routinely monitored for faults-to-ground. BTW grounding (earthing) ABSOLUTELY DOES NOT attract Lightning (another topic- but actually the opposite is true). Anyone that believes earthing attracts Lightning needs to write a peer review ASAP challenging the opinion of thousands of electrical engineers and submit it to IEEE for immediate review and update.
curious... is there a 8ft driven ground rod at the array??? and have you thought of installing a couple of air terminals to mitigate system damage in case of a direct lighting strike??? it's my experience that lighting rods do not attract lighting... they just redirect the energy to an earth ground (path of least resistance) if a bolt is headed your way...
It is not the inductance which is generally the problem but the heat dissipation, if you bundle wires heat cannot be dissipated efficiently and.you have to derate the wire.
@@tanishqbhaiji103 yes - but in the case of a lightning strike as suggested by the original poster as a reason for wanting this alleged inductance, we're talking about millions of volts and tens of thousands of amps. Derating is no longer a relevant discussion point any more than the inductance of an air-cored coil of wire is.
@@tanishqbhaiji103 That was precisely my point. What exactly did you think I meant when I said that the inductance of an air-cored coil was irrelevant in the context of a lightning strike? What did you think I meant earlier when I said that a small coil of wire like that will make no measurable difference to the effect of a lightning strike?
By grounding, you are essentially creating a lightning rod to blow up your system. When it rains the salts in the ground become conductive and make a path for lightning from the ground to meet the lightning in the sky
Would that comment apply to the engineering design for radio, microwave, and cellphone towers as well? Should those designs float (eliminate) the ground?
@@Ekanselter I don’t know- I was just pondering as I saw a video about how lightning comes from the ground? Maybe insurance companies don’t require lightning rods on our houses for a reason. Trees get wet down to the roots create a lightning rod. So if you have tall trees around, your probably okay, but don’t stand under the tree.
Howdy from Texas! I am about to mount 24 130 watt panels on the roof of me 40' Tour Bus Tiny Home. Lol (stationary). I am using an aluminum structure to mount them too and that is screwed into the metal bus roof. Is there a problem with this? Is it dangerous?
There are a couple of things to consider. First, make sure they are very securely attached to the roof. Even if you are not moving, high winds create significant loads from the large surface area of the panels. Depending on the wind and the angle, it could be enough to tip the buss over. Second, be aware, if you string multiple panels together in series, you can achieve very high and very dangerous voltages. The optimizers on the system in this video keep every panel to a safe 1V. When you string panels together without optimizers or micro inverters, you don't have that protection. If you don't understand the electrical part, get an electrician to help you with the connections. I talk about understanding voltages in this video: ruclips.net/video/ZFbKtGSkhsE/видео.html I also talk about connecting charge controllers and inverters in this video: ruclips.net/video/OwfGLu8IY_M/видео.html
Hi Dave, first thank for sharing your experinces. Good job ;-) I have a comment to the explanation of wire coils. Everything that was said is true, BUT the main problem with coils is if comes high voltage because of thunder. I've worked in telecommunication company for more then 25 years and I saw what happens with even one turn so my suggestion is NEVER use coils in outdoor installations. Well, we can discuss the principle of Farraday's cage.... By the way the explanaion assumes case with one wire, but in reality there are two, so the magnetic field is diferent and counting is wrong. However the main principle stays the same, so no complaints.
Thanks for sharing your experience on the impact of coiled wire with lightening strikes. Could you explain further what happens with coiled wire in a lightening strike? Thanks!
@@ProjectsWithDave Well, what I tried to say is, that lightning has a huge amount of energy and as such create very strong magnetic field, so every coil in it generates high voltage. It's like a transformer without a core. But if the coil is let say "inside" the PROPERLY grounded construction, it is for example the same effect as if you are in car during a storm. You are absolutely safe because of Farraday's cage principle. Now depends, how is your supporting construction made. If it is all metal, every leg should be connected and grounded. By the way grounding point has to be lower then grounded point-simply imagine, that current is like water and water everytime flows down. Hope it is comprehensive. Sorry, English is not my mother tongue, so it is not easy to me to explain all details.
@@ProjectsWithDave Don't listen to this guy's 25 years of experience. Coil those wires and move on with your day. These idiots commenting over stupid shit like the 0.00001 % chance that a lighting storm would fry a panel or two isn't worth one second of your time. I could go hunt down a physicist and he would have a hard time computing the increase in voltage due to the turns ratio of a coiled wire to a lighting bolt. Stop with the stupidity. I bet you money Mr. Novak is a uneducated technician who doesn't know anything about differential equations. I'm an electrical engineer and I have no problem with your install. These nut bags read a Wikipedia article and suddenly they have a master's degree in electrical engineering.
@@Impedancenetwork I am high educated engineer, by the way... Maybe American standards are different then the Eruopean.... and my English is not as good to discuss every detail. I trust my knowledge and experience. That's all...
I agree with you, the analysis in the coil is not accurate. Both line 1 and line 2 wires were coiled together. This will cancel out any field generated by each wire, and since this is DC then this will not even generate one pulse. Plus it's air core, what induction. If your generating a very high frequency oscillator, maybe, if you coil one wire. On lightning strikes, all conductors will act like an antenna and absorbed EMF. That's why you said even with one coil. The closer you get to the lightning strike, the greater EMF you'll collect. In our telecomm installations, all cables exposes atmosphere are installed with surge protection. But then, other cables, like for instrumentation were not installed with surge protection. Only when the area is prone to lightning surge protection are installed. Grounding is very important. It's an Electrical Code requirement anywhere. Explanation is good. Same reason for the Code. => Personal Protection on any ground fault and lightning protection.
How do you have your array earth grounded? Mike Holts says if you use a ground rod that array needs to be bonded to the main house ground so that you only have one ground, other people/electricians say a separate non bonded rod is safe, do you have a rock solid explanation?
The array is bonded to the household main ground rod. However, the racking is bonded to the same conductor and the posts are buried more than 3' in the ground effectively making them ground rods as well.
Long wire increases the resistance which will increase the losses. However, it isn't worth cutting and remaking all the connections to save $0.50/year in power.
Greetings Dave, I live in Phoenix, AZ, and in 2019, I had a 22 @ 305 watt panel system installed on the roof of my home. Ever since then, the 2.4 gb wifi network inside my home is virtually worthless while the sun is shining. BTW, the 5.0 gb wifi signal seems unaffected, but most of my devices are 2.4 gb only. Once the sun goes down, and the panels are no longer operating, the wifi signal improves back to what seems like 'pre solar' strength and quality. Can you or any of you viewers explain what may be happening and ways to correct the situation? I am wondering if any coiled wires under the panels, are creating magnetic fields or EMF or anything like that which would cause the interference? I know next to nothing about electricity, so I really do not know what I am talking about. The installer company sent out their 'best' troubleshooter, and he shut down the entire system at the inverter, but the signal did not improve during the ten minutes or so the system was off. Basically, since the system is producing the quoted electricity, they are not interested in searching further for a solution. Any help you may provide would be greatly appreciated. Dave
I have heard ham radio operators complain about interference from solar systems. Unfortunately, I haven't researched the problem. Do you have, optimizers, micro inverters, or rapid shutdown modules connected to each panel? If so what type? Even when the array is turned off, these modules still have power from the panels can could be producing interference.
Yes, there are two videos with combiner box upgrades. Budget combiner box: ruclips.net/video/uS8cqppAy7s/видео.html Upgrade with breakers and surge protection: ruclips.net/video/IZjISqEWglU/видео.html
When I was grinding our solar array to a ground rod, I was getting voltage on the ground wire. It was reading 30 volts AC voltage. I haven't been able to find out why. Any ideas? I checked all the grounds and neutrals in the inverter, panel, and transfer switch.
hi don't you think your ground cable is not thick enough? and why don't ground it near the panels? (I mean why do you combine solar panel grounding with your home ground) is it safe? is there any reason for it?
@@ProjectsWithDave I'm new to this subject, and also trying to build offgrid solar system for my home. Is it ok to use same grounding rode to ground solar panels and house AC grounding?
Grounding a solar array is useless if a positive wire from the solar array happens to come in contact with the array it would not pass any current through the bond wire thier is no reference on the bond wire to the negative of the array it is a isolated system just brings everything bonded to the positive potential of the array.
If a positive wire touches the frame which is bonded to ground, they have to be at the same potential, which is also equal to ground. If there is no potential difference between the frame and the ground you can't get shocked.
@@ProjectsWithDave you wouldn't get shocked either way bonded or not unless you were also touching the negative lead on the solar array as the negative of the pv system is not bonded to ground. Without bonding the negative of the solar array to earth thier is no potential difference to any bond any where meaning no shock, no current passing through the bonds. Bonding the solar array just makes the potential of every bonded electrical system connected to it live in the case of a fault to reference of the negative of the pv array nothing else. If you don't beleive me take a positive wire from your solar array touch it to the frame with a current meter on it set to dc and thier will be 0 amps flowing through it unless you have a fault so.e where else that has bonded the negative lead to ground.
The orientation of the panels is a significant factor in their performance. Maybe someday when panels are significantly cheaper their orientation won't be so critical.
Hey good vid, was worried about my solar cables coiled up under each panel, so now you've put my mind at ease. I do have one problem, and It's that my 6x 405 panels are in series and output around 200V. They are mounted on rails and the rails are screwed into a wooden frame. I do get an electrical tingle sensation when I touch the rails or the side of the panels. It's not like an electric shock, but an uncomfortable tingle feeling which is worrying me. Is this normal? My panels are not grounded at all tho.
Proper Bonding and Grounding is very important but it is NOT a solution to your problem - while it will probably eliminate the tingle your 'snake in the grass' is still there. Using another example - if your Washing Machine was doing the same thing hopefully you would not simply 'ground' it to solve the problem. You have at least one (small for now) ground-fault in your system leaking DC+ to the metallic structure. By depending on Grounding to 'drain off' the fault current you still have a potentially dangerous situation lurking in the background.
You can get the cost information in this video: ruclips.net/video/PNTO83FvaL4/видео.html The supplier is in the description, I used Ready Rack. The description also has time stamps so you can jump right to the racking portion.
I'm a retired electrical engineer, and I can tell you with certainty the loops don't matter. By the way, the loop you are pointing to has both wires (plus and minus) paired together so their magnetic fields would mostly cancel; that means those loops have a lot less inductance than you think. But it doesn't matter. The whole DC string is one big loop anyway, so looping the cable just increases inductance slightly. And that's not a bad thing. A bit of added inductance just means a little more spark on the disconnect contacts when you open it.
As an active but 65yo electronics engineer, you are correct.
Your videos were one of the primary sources of encouragement that gave me the confidence I could install my own 37 panel system!! Everything was delivered last week and we are about halfway through installing mounts and rails. Thanks for all the great videos!
Grounding is not for lightening, it won't do much against a strike, It's for transient over voltages. You're also missing distinction between bonding and grounding. Bonding creates a uniform voltage plane. Grounding is primarily to provide a low resistance path to trip the breaker.
Grounding, as in connecting the metal structures to the earth, is not for tripping a breaker.
@@altuber99_athlete I'm well aware but most people call the Equipment grounding conductor and Grounding electrode conductor... just ground. Outside electricians or EE's few realize they serve a different purpose and how they function to do so.
@@steven7650 Oh, I thought you didn’t know, since you said “Grounding is primarily to provide a low resistance path to trip the breaker”, which is incorrect. Bonding (connecting the neutral bus bar and ground bus bar together at the main panel) is done for that.
What grounding (connecting the neutral/ground bus bars of the main panel to the planet Earth ground) does is allow excess charges (from lightning and electrostatic) to be mitigated.
Grounding + bonding establishes the neutral-to-ground voltage to zero or near zero volts at all normally non-current-carrying metallic pieces.
Or that’s how I look at it.
@@altuber99_athlete Understandable as most just use ground the way I remarked which as you correctly point out is incorrect or at least incomplete. Bonding is more for creating an equipotential plane around an object which may become energized, think pool, hot tub or such. The neutral to earth bond at the service sets the reference though it's very minimal because North American Utilities use a multipoint ground system already. As you said it's more for directing excess current to the earth in case of strikes.
Respectfully I seriously and absolutely disagree. The Grounding (earthing) intended purpose by design is NOT to provide a 'low resistance path to trip the breaker' as stated! Earth resistance is unpredictable - how can it be a part of an engineering design to operate in a fault? Point being - NEVER depend on 'dirt' to provide a low resistance path to the source.
Another thing about zip ties... you want to use relatively wide zip ties to prevent chaffing from cutting through the cable over time. Wide zip ties tend to be larger than the ones I see in the video. I know it seems like a waste of plastic, but it makes a big difference. I've taken apart old solar systems (15+ years old) where the zip ties had done more damage to the wiring than just leaving it loose would have.
Great suggestion. Thanks for the real world feedback!
Never thought of that. Thanks and greetings from Jamaica.
I wish people would stop saying that grounding panels is for lighting protection, it really isn't. Lightening protection is a completely different structure isolated from the structure you are trying to protect. If you think a 10 or 6mm² cable is going to protect fromm 1000's of volts and amps it won't. Directly grounding a structure actually makes it more attractive to Lightening. Good information on the DC coiling
Nice having Jordan on the show. Thanks dad. Thanks again for the information.
Sure get him to calculate the wind load on those what seems like small pipes used for the racking system. Love your input as you are active.
Thanks! The pipes may appear small in the video, but they are a heavy wall pipe. We get 60mph+ winds here fairly regularly and the rack holds steady with no issues.
It is not the inductance which is generally the problem but the heat dissipation, if you bundle wires heat cannot be dissipated efficiently and.you have to derate the wire.
Hi Dave, love the content. It would be interesting to give Jordan another project and have him take a look at voltage loss from panels to the inverter. I suspect your wiring is throwing a bit of heat and your system's a bit leaky.
Thanks! Great Idea! I did a calculation on the losses from the array to the inverter before I installed the system. That showed the loss would be very small, however, I have never checked the actual situation. I'll have him do that. : )
@@ProjectsWithDave Don't listen to Ed Stiver. Jesus man I'm an electrical engineer. I design power systems for a living and I would worry one second over that coiled wire. It is amazing the amount of BS people worry about. Not one person, such as Ed, could calculate the "leaky"-ness of your system. You can spend 3 weeks analyzing stupid shit that amounts to no significant difference. When you know what you're doing you don't need a calculator to verify it.
@@Impedancenetwork The key is knowing what to worry about, and what is unimportant minutia.
Interesting - assuming we are talking about leakage-to-ground, I will be happy to check that for you using a simple Fluke 1587 with no calculations required! No big deal and no cost. Since you have so much knowledge, it might be good to submit a paper letting IEEE know that calculations are worthless if you really understand electrical engineering concepts.
Actually, even Jordan's statements are overstated. For DC - yes not an issue. Even for AC, though, from what I can see you have both wires (ie. supply and return path) coiled up together and lying right next to each other. The fields largely cancel out and so your actual inductance will be much lower - likely negligible. Similar structures are used in electronic components routinely - for example the bifilar windings of wirewound resistors which are specifically designed to reduce the inductance of the resistor to negligible values or common-mode chokes which have negligible impedance to your incoming AC power, but noticeable impedance to common-mode voltages picked up via EMR and other noise sources.
Very informative. Looking forward to more videos.
The problem with grounding is when lighting strikes the wet ground it travels up your grounds and takes out your fret board on the inverter. I learned that the hard way. I cut all my grounds and only use battery grounding. Haven't had that problem again for 28 yrs.
Thats not code
How will the lightning energy coming up FROM the earth into your ground rod - and then into your equipment physically destroy the equipment? If your theory is valid, then a 3,000,000 volt lightning strike hitting an airplane would completely destroy it in a massive ball of fire. In comparison, a bird landing on a high-voltage power line should be incinerated.
You can always connect your strings using Cross-Connection method, nip one slip one. Advantage is also get same lengths on your + and - wires and neater cabling. Not all makes has longer cables eg Longi panels
HOWdy P-W-E-D,
Thank you for the GROUNDING Hints & Suggestions
COOP
...
Please make such a video for the bifacial ground installation
I will have some related content this summer.
Dave, I notice that a 9.36KW unboundsolar kit with SolarEdge optimizers costs around 14K as of today. Your system costs were closer to 10.6K for your "kit". Why the difference? Did costs go up or did you save money clipping?
The kit posted online includes racking for roof mounting, but I used the Ready Rack ground rack. You can see my cost breakdown by part here: ruclips.net/video/PNTO83FvaL4/видео.html
Great video Dave!! thanks - Question for the future.. have you washed the panels yet? Should you avoid city water and use distilled? Any certain brushes to use?
Thanks! Great question! I deliberately did not manually wash the panels since install two years ago. I want to understand if cleaning is a significant consideration for ground vs roof installations. I have been watching build up of dust and bird poop and seeing how much of it the rain takes care of. So far, not cleaning them hasn't been a noticeable impact to performance. I'll keep your suggestion in mind for a future video once I have determined the best approach.
I clean mine twice a year .. and bird poo etc as needed.. and possibly clean anyway.. as I think the dirt or pollution can be abrasive and acidic .. and I want them to be as efficient as possible in cloudy weather.
@@mySeaPrince_ In cloudy weather, it is most likely going to rain & wash away the dirt. Why clean manually?
@@shrujanamsyama9940
Over the decades I've had various types of panel, I've even used a surface treatment which does help..
Just like a greenhouse, car or home windows they all get a build up of dirt that the rain, even hail or snow doesn't remove...
Looks great. Same setup as my unistrut/4x4 pt post, 20kw array.
Thanks! 20kW is a nice size array.
Hi and huge Like from Estonia! Everything is clear and well explained! Only one question about strings. Why not to make "left" and "right" U-s and connecting box in center? Then You dont need extra cables.
The corner of the array is closest to the house.
Question: you state that you run your DC leads “all the way back to the house”. Is there a preference in running DC lines (like you) a long distance or a converted AC line a long distance? I’m setting mine up now.
Use black zip ties they are better in UV.
The zip ties linked in the description are designated UV stable.
Where did you get the racking. And how much did it cost?
You can get the cost information in this video: ruclips.net/video/PNTO83FvaL4/видео.html
The supplier is in the description, I used Ready Rack. The description also has time stamps so you can jump right to the racking portion.
The fact that you have to coil the wires means there is unnecessary length which does add resistance. It must not be enough for concern because no one has ever mentioned it.
The resistance from the extra wire length is small enough that it's not worth the time and expense to shorten all the wires.
Today's racking systems (not that kindorf) utilize mounting hardware that bonds modules to the rail (Unirac, Ironridge, SnapNRack, etc.)
Correct. Only need to ground the rails.
Where did you buy the grounding clips between panels? Nice job 👍
Thanks! I put a link in the description. You can get the Stainless Steel Cable Clips here: amzn.to/3e4qCNm
@@ProjectsWithDave He asked about the "grounding" clips between panels. Your link is for "cable management" not grounding. I'd like to know also, thanks! Those clips that you put the multi-meter on look like they would be cheaper than the solid copper wire 4 awg that I'm using to connect my twelve panels to each other using the older clip with twist bolt that you also showed.
Find More information for this project and others on my website: projectswithdave.com
Other related solar videos that may be helpful:
Full Solar System Install: ruclips.net/video/_xA6qOwnYbM/видео.html
3 Solar Panel Wiring Issues Answered: ruclips.net/video/i7vHEHB3a-M/видео.html
Check out the first year performance results here: ruclips.net/video/BatTeSq05rU/видео.html
See the total system cost here: ruclips.net/video/PNTO83FvaL4/видео.html
And How to size your solar system here: ruclips.net/video/rbFnZqA0GCI/видео.html
4 Things to Know About Solar in the Snow: ruclips.net/video/vY3PufzPUnI/видео.html
Ground Vs Roof Mount Solar: ruclips.net/video/w-iS_8e7n60/видео.html
How to Get A Permit For Your Solar System: ruclips.net/video/imiEYDHLG4A/видео.html
How to Crimp MC4 Connectors: ruclips.net/video/oH3LqTu4B8E/видео.html
How deep should the grounding rod be in the ground. What determines the depth? The ones at the home/hardware stores are 8 feet long. Why 8? Or 10 or 6?
It largely depends on the soil type. The important thing is making a good electrical connection with the soil.
Do you think you'll increase the array size or add batteries soon?
I'm considering increasing my array size. I believe I can still get a reasonable payback period for some increase in size. As for batteries, the technology needs to improve quite a bit from a cost perspective before it can be justified. It is possible that in the near future electric cars can provide the dual purpose of a household battery backup. Things are changing quickly in the battery area so I think I will wait on that for now. Thanks!
@@ProjectsWithDave Lithium hasn't changed in decades LOL. And you wouldn't want your pos electric car to go to the junkyard even faster using it as a power source.
Thanks very interesting 👍🏻
Glad you enjoyed it!
Doesn't having two earth/ground points - solar array and then main panel - create a really dangerous potential for a ground loop? Wouldn't you need to bond the two ground rods?
You can't really avoid a ground connection at the array. The metal posts are buried several feet into the ground and the frame is connected to the grounding system. The code in my area required me to connect my array to my house ground using a #6 copper conductor.
If the aluminum is not grounded because of the anodizing you are protected by the same anodizing layer.
Yep protects you yet lightning will jump right through it. Win.
Great video. I too have a solar system. I was hoping you could clarify grounding for me.
Did you ground the negative conductor from your panels? If yes grounding makes sense to protect people from damaged panels as they would be completing the circuit to ground.
If you didn't ground the negative there is no circuit to ground so there is no risk to people.
Grounding for lightning strikes. Why do we want to encourage lightning to go through the panel frames? Massive DC amps will cause considerable damage. Would it be safer to have separate lightning rods at the highest point of you system that are wired to your grounding rods completely separate from the panels?
Sorry, I'm not an expert on lightening strikes and bonding to be able to give you the benefits and risks of lightening rods. However, I don't think I would want to intentionally attract lightening to the area. I did not connect the negative conductor of the PV panels to ground. However, if the frames are not bonded to the grounding system they could become energized by a positive conductor that was damaged and touched an isolated frame. As long as the frame is bonded to the grounding system any short will be directed to ground rather than through you.
Your son is an electrical engineer. What are his thoughts?
@@ProjectsWithDave additionally if the panel is damaged and the positive is now connected to ground through the frame, If you touch the negative conductor you will get shocked
Grounding the Negative of a properly designed DC power system is fine but it may include one concern - a Ground Fault (the DC+ shorted to Ground) of sufficient magnitude will open the source Fuse/Breaker. As a result the problem then becomes finding the fault itself so you can fix it and get your power back on! Good luck unless you are a professional! Bottom-line, floating the DC Negative is not a problem at all if properly designed, installed, and routinely monitored for faults-to-ground.
BTW grounding (earthing) ABSOLUTELY DOES NOT attract Lightning (another topic- but actually the opposite is true). Anyone that believes earthing attracts Lightning needs to write a peer review ASAP challenging the opinion of thousands of electrical engineers and submit it to IEEE for immediate review and update.
curious... is there a 8ft driven ground rod at the array??? and have you thought of installing a couple of air terminals to mitigate system damage in case of a direct lighting strike??? it's my experience that lighting rods do not attract lighting... they just redirect the energy to an earth ground (path of least resistance) if a bolt is headed your way...
Each Post is galvanized steel and bonded to the grounding system, I did not think it necessary to add another grounding rod.
I think it is good to coil the dc wires. In case of lightning strike, the inductors decrease the lightning current.
A small coil of wire like that will make no measurable difference to the effect of a lightning strike on your equipment.
Looks like a good place for a pooping birds nest to me.
It is not the inductance which is generally the problem but the heat dissipation, if you bundle wires heat cannot be dissipated efficiently and.you have to derate the wire.
@@tanishqbhaiji103 yes - but in the case of a lightning strike as suggested by the original poster as a reason for wanting this alleged inductance, we're talking about millions of volts and tens of thousands of amps. Derating is no longer a relevant discussion point any more than the inductance of an air-cored coil of wire is.
@@tanishqbhaiji103 That was precisely my point. What exactly did you think I meant when I said that the inductance of an air-cored coil was irrelevant in the context of a lightning strike? What did you think I meant earlier when I said that a small coil of wire like that will make no measurable difference to the effect of a lightning strike?
great info, thanks !!!
Glad it was helpful!
Hi, where can I find your grounding straps between panels?
You can get them from dynobond.com here is the purchasing page: 973193.shop.netsuite.com/dynoraxx?sort1desc=F&sort1=Item_ONLINECUSTOMERPRICE
I also have a crack… 😂
Cracking up over having a crack, LoL.
Where did you get the grounding wire with the clips on each end that attach to the panel frames?
This is the supplier website: dynoraxx.com/grounding/dynobond/
By grounding, you are essentially creating a lightning rod to blow up your system. When it rains the salts in the ground become conductive and make a path for lightning from the ground to meet the lightning in the sky
Would that comment apply to the engineering design for radio, microwave, and cellphone towers as well? Should those designs float (eliminate) the ground?
@@Ekanselter I don’t know- I was just pondering as I saw a video about how lightning comes from the ground? Maybe insurance companies don’t require lightning rods on our houses for a reason. Trees get wet down to the roots create a lightning rod. So if you have tall trees around, your probably okay, but don’t stand under the tree.
Howdy from Texas! I am about to mount 24 130 watt panels on the roof of me 40' Tour Bus Tiny Home. Lol (stationary). I am using an aluminum structure to mount them too and that is screwed into the metal bus roof. Is there a problem with this? Is it dangerous?
There are a couple of things to consider. First, make sure they are very securely attached to the roof. Even if you are not moving, high winds create significant loads from the large surface area of the panels. Depending on the wind and the angle, it could be enough to tip the buss over. Second, be aware, if you string multiple panels together in series, you can achieve very high and very dangerous voltages. The optimizers on the system in this video keep every panel to a safe 1V. When you string panels together without optimizers or micro inverters, you don't have that protection. If you don't understand the electrical part, get an electrician to help you with the connections. I talk about understanding voltages in this video: ruclips.net/video/ZFbKtGSkhsE/видео.html
I also talk about connecting charge controllers and inverters in this video: ruclips.net/video/OwfGLu8IY_M/видео.html
Hi Dave, first thank for sharing your experinces. Good job ;-)
I have a comment to the explanation of wire coils. Everything that was said is true, BUT the main problem with coils is if comes high voltage because of thunder. I've worked in telecommunication company for more then 25 years and I saw what happens with even one turn so my suggestion is NEVER use coils in outdoor installations. Well, we can discuss the principle of Farraday's cage....
By the way the explanaion assumes case with one wire, but in reality there are two, so the magnetic field is diferent and counting is wrong. However the main principle stays the same, so no complaints.
Thanks for sharing your experience on the impact of coiled wire with lightening strikes. Could you explain further what happens with coiled wire in a lightening strike? Thanks!
@@ProjectsWithDave Well, what I tried to say is, that lightning has a huge amount of energy and as such create very strong magnetic field, so every coil in it generates high voltage. It's like a transformer without a core. But if the coil is let say "inside" the PROPERLY grounded construction, it is for example the same effect as if you are in car during a storm. You are absolutely safe because of Farraday's cage principle.
Now depends, how is your supporting construction made. If it is all metal, every leg should be connected and grounded.
By the way grounding point has to be lower then grounded point-simply imagine, that current is like water and water everytime flows down.
Hope it is comprehensive. Sorry, English is not my mother tongue, so it is not easy to me to explain all details.
@@ProjectsWithDave Don't listen to this guy's 25 years of experience. Coil those wires and move on with your day. These idiots commenting over stupid shit like the 0.00001 % chance that a lighting storm would fry a panel or two isn't worth one second of your time. I could go hunt down a physicist and he would have a hard time computing the increase in voltage due to the turns ratio of a coiled wire to a lighting bolt. Stop with the stupidity. I bet you money Mr. Novak is a uneducated technician who doesn't know anything about differential equations. I'm an electrical engineer and I have no problem with your install. These nut bags read a Wikipedia article and suddenly they have a master's degree in electrical engineering.
@@Impedancenetwork I am high educated engineer, by the way...
Maybe American standards are different then the Eruopean.... and my English is not as good to discuss every detail. I trust my knowledge and experience. That's all...
I agree with you, the analysis in the coil is not accurate. Both line 1 and line 2 wires were coiled together. This will cancel out any field generated by each wire, and since this is DC then this will not even generate one pulse. Plus it's air core, what induction. If your generating a very high frequency oscillator, maybe, if you coil one wire.
On lightning strikes, all conductors will act like an antenna and absorbed EMF. That's why you said even with one coil. The closer you get to the lightning strike, the greater EMF you'll collect. In our telecomm installations, all cables exposes atmosphere are installed with surge protection. But then, other cables, like for instrumentation were not installed with surge protection. Only when the area is prone to lightning surge protection are installed.
Grounding is very important. It's an Electrical Code requirement anywhere. Explanation is good. Same reason for the Code. => Personal Protection on any ground fault and lightning protection.
Connected to houses eathing system. Doesn't that mean lightning is going to travel into your house now?
It should be directed to the ground rod.
@@ProjectsWithDave yes, every house ground is eventually connected to ground rod but should you mix lightning ground path with house electrics?
How do you have your array earth grounded? Mike Holts says if you use a ground rod that array needs to be bonded to the main house ground so that you only have one ground, other people/electricians say a separate non bonded rod is safe, do you have a rock solid explanation?
The array is bonded to the household main ground rod. However, the racking is bonded to the same conductor and the posts are buried more than 3' in the ground effectively making them ground rods as well.
@Projects With Everyday Dave so basically a secondary rod (Buried rack) bonded to house ground
Yes, that's the effective result.
@Projects With Everyday Dave it ses to be a very heated discussion in some groups, did you use 6 awg?
Yes, that is what the inspector required in my area.
why don't you try to shorten the wires? more wire means probability voltage drop increase.. isn't it?
Long wire increases the resistance which will increase the losses. However, it isn't worth cutting and remaking all the connections to save $0.50/year in power.
Greetings Dave,
I live in Phoenix, AZ, and in 2019, I had a 22 @ 305 watt panel system installed on the roof of my home. Ever since then, the 2.4 gb wifi network inside my home is virtually worthless while the sun is shining. BTW, the 5.0 gb wifi signal seems unaffected, but most of my devices are 2.4 gb only.
Once the sun goes down, and the panels are no longer operating, the wifi signal improves back to what seems like 'pre solar' strength and quality.
Can you or any of you viewers explain what may be happening and ways to correct the situation?
I am wondering if any coiled wires under the panels, are creating magnetic fields or EMF or anything like that which would cause the interference? I know next to nothing about electricity, so I really do not know what I am talking about.
The installer company sent out their 'best' troubleshooter, and he shut down the entire system at the inverter, but the signal did not improve during the ten minutes or so the system was off. Basically, since the system is producing the quoted electricity, they are not interested in searching further for a solution.
Any help you may provide would be greatly appreciated.
Dave
I have heard ham radio operators complain about interference from solar systems. Unfortunately, I haven't researched the problem. Do you have, optimizers, micro inverters, or rapid shutdown modules connected to each panel? If so what type? Even when the array is turned off, these modules still have power from the panels can could be producing interference.
Did you do a combiner box video?
Yes, there are two videos with combiner box upgrades.
Budget combiner box: ruclips.net/video/uS8cqppAy7s/видео.html
Upgrade with breakers and surge protection: ruclips.net/video/IZjISqEWglU/видео.html
When I was grinding our solar array to a ground rod, I was getting voltage on the ground wire. It was reading 30 volts AC voltage. I haven't been able to find out why. Any ideas? I checked all the grounds and neutrals in the inverter, panel, and transfer switch.
Sorry, I don't think I can help diagnose that through internet chat. I suggest you get a local electrician to support you.
Off topic but do you use branch connectors in your design?
Not in this setup.
Are those, micro inverters?
DC/DC optimizers. They hold the DC voltage at about 400V for the inverter.
hi don't you think your ground cable is not thick enough? and why don't ground it near the panels? (I mean why do you combine solar panel grounding with your home ground) is it safe? is there any reason for it?
Code requires a 6 awg ground conductor connected to the main ground rod for the house. However, the racking also acts as a ground.
@@ProjectsWithDave but you use to connect two panels with little bit thin cable..
@@ProjectsWithDave I'm new to this subject, and also trying to build offgrid solar system for my home. Is it ok to use same grounding rode to ground solar panels and house AC grounding?
sorry my mistake I think you used 6 guage bare copper cable. 🙂
Man you have 2 views, I'm 1 of them great! good video though
Hey, thanks!
Wirenuts have less impedance than wagos though. Trade offs
I replaced the wirenuts in the J-box in this video: ruclips.net/video/uS8cqppAy7s/видео.html
Grounding a solar array is useless if a positive wire from the solar array happens to come in contact with the array it would not pass any current through the bond wire thier is no reference on the bond wire to the negative of the array it is a isolated system just brings everything bonded to the positive potential of the array.
If a positive wire touches the frame which is bonded to ground, they have to be at the same potential, which is also equal to ground. If there is no potential difference between the frame and the ground you can't get shocked.
@@ProjectsWithDave you wouldn't get shocked either way bonded or not unless you were also touching the negative lead on the solar array as the negative of the pv system is not bonded to ground. Without bonding the negative of the solar array to earth thier is no potential difference to any bond any where meaning no shock, no current passing through the bonds. Bonding the solar array just makes the potential of every bonded electrical system connected to it live in the case of a fault to reference of the negative of the pv array nothing else. If you don't beleive me take a positive wire from your solar array touch it to the frame with a current meter on it set to dc and thier will be 0 amps flowing through it unless you have a fault so.e where else that has bonded the negative lead to ground.
You don’t need to cut the zip ties, they will fall off on their own
Black cable ties handle the sun much better.
😀
You seem legit not sure you seem too smooth
That's probably because I'm just an average guy bringing you what I've learned. Maybe the "smoothness" will improve over time. : )
people spend all this money on racks and all you have to do is put them on the side of your home like windows.
The orientation of the panels is a significant factor in their performance. Maybe someday when panels are significantly cheaper their orientation won't be so critical.
Hey good vid, was worried about my solar cables coiled up under each panel, so now you've put my mind at ease. I do have one problem, and It's that my 6x 405 panels are in series and output around 200V. They are mounted on rails and the rails are screwed into a wooden frame. I do get an electrical tingle sensation when I touch the rails or the side of the panels. It's not like an electric shock, but an uncomfortable tingle feeling which is worrying me. Is this normal? My panels are not grounded at all tho.
This is not normal! You need to have all the panel frames bonded together and connected to a system ground. Usually 6AWG copper.
Proper Bonding and Grounding is very important but it is NOT a solution to your problem - while it will probably eliminate the tingle your 'snake in the grass' is still there. Using another example - if your Washing Machine was doing the same thing hopefully you would not simply 'ground' it to solve the problem.
You have at least one (small for now) ground-fault in your system leaking DC+ to the metallic structure. By depending on Grounding to 'drain off' the fault current you still have a potentially dangerous situation lurking in the background.
Where did you get the racking. And how much did it cost?
You can get the cost information in this video: ruclips.net/video/PNTO83FvaL4/видео.html
The supplier is in the description, I used Ready Rack. The description also has time stamps so you can jump right to the racking portion.