Does my 13kW Offgrid Solar System require Grounding? Is it Grounded? 

Will, can you please give us a visualization of different grounding procedures? Correct vs incorrect. Grid tie vs off grid.

Your videos are a wealth of infomation , thanks for taking the time to educate us newbies , I specialy appreciate your approach to saftey and in depth explanations .You helped me build my first off grid sep up for my cabin few years ago and its still going strong . Keep up the awesome work mate !!

Fault current travels back to the source, not to the earth. Mike Holt’s Grounding versus Bonding videos are great source of information. I have to stay up with the NEC every 3 years. He has been teaching for over 40 years. As a side note Will, if it was not a stand alone system, or if you were to use this system for a home back up in an emergency power outage, through an interlock kit, make sure your Neutrals and Grounding conductors will be separated in this Square D panel. 6/4 cable would go back to the interlock breaker. Also, only one neutral conductor is allowed per terminal. Otherwise you will have an objectionable currents flowing on all metal parts of your electrical system - dangerous condition to have. I keep finding this in people’s homes when someone would add a sub panel. The grounding and grounded (neutral) conductors have to be connected only in one point in the house - at the main breaker panel.

The comprehensiveness of this video makes it a true standout. I have struggled to explain my particular situation, and I now understand that I need to describe other situations that would require earth grounding, how and why may be the missing piece. Truly excellent work!

Mike Holt is great. I used to use his videos in my Electrical Trades Classes. For those people on here that want drawings, they should go look at Mike Holt. He does great drawings.

Thank you Will for expounding on this ground discussion going on on your site. I have learned a lot from Mike's lecture and from your comments. Now I need to go unhook my ground rod from my array!! This is way more complicated than most people think especially when you add in lightning.

It's unfortunate that the National Electrical Code uses the term grounding and grounded. I was a member of the NEC section for many years and there has always been confusion. Many of us believe that the current terminology should be canned and use the terms earthing and bonding to help eliminate confusion. Many other countries use this terminology and it is much simpler.

Thanks for these great videos! We just bought a 12 kw system on Sat for our off grid home and these videos couldn't have come at a more opportune time!

I have read many comments and happy to see so much interest and concern over safety and desire to become more educated on it. Please do so! One of the issues, imo, is our words.... take ground, neutral and line. We all use ground" wrong at times. Many times I say ground when I mean desired return current path, which in houses is called the neutral.... which is (typically) strapped at the box to earth ground. And speaking of ground loops with myself and other saying how they are bad... when the electric company safely has created ground loops with your neighbor's earth ground rod.... all depends on where the loops are. I'm happy to see these discussions : ) Use Good sense... Common sense? def common these days... might not be the best! An example of a play with words intentionally when the understanding of "common sense" to make good decisions is not properly conveyed. Same as more recent technical words like ground etc... Will does good with follow up and education, ya'll do the same now, ya hear?

Part 2 Grounding Update: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-X3QA9T_O1g0.html Update: this system will never pass an inspection and never needs to. It is Offgrid and there is not a single permit required for connecting a battery to an inverter, and using a couple of panels laying on the ground. People are trying to reference NEC?? Why? This inverter isn't even listed. Sure it's compliant and certified, but it would still fail inspection. And that's fine. I'm not connected to grid (besides back up battery charger which isn't grid tie. It's a battery charger). And I only care about safety and that's it. Original pinned comment: Oh and I'm adding ac supply at the input on it's own breaker today (and programming it to only use the battery charger. Not bypass!). That's why I said it has true earth ground in one of my given examples. When this system is supplied by a true earth ground ac circuit, I do not need to separate the grounds and neutrals on my panel because the transfer switch will be open, and the output of this inverter will not act as a sub panel supply. This is because the input only supplies a battery charger in my configuration. If I am using it as a UPS (which requires programming it as such), and I have a large dedicated breaker supply from my sub panel, (which I will not do), then I will need to separate ground and neutrals. That would make a separate connection, and it is not isolated. When the ATS inside the inverter is connected only to the battery charger, it is isolated. But still susceptible to high voltage if a ground loop was created. If it was not grounded when not connected to ac input, that is fine. There are plenty of standalone systems without grounding. Such as an RV electrical system with inverter when not connected to shore power. Same thing. So it really depends on how you use it. If you are using it not as a solar power system, and instead as a stand-alone UPS, then I could see why you do not want to bond the ground and neutrals at the ac output. But that is the only exception I can think of. ~~~~~~~~~~~~~~~~~~~~~~~~~ Does off-grid solar confuse you? Check out my DIY friendly website for solar system packages and product recommendations, and so much more! www.mobile-solarpower.com Join our DIY solar community! #1 largest solar forum on the internet for beginners and professionals alike: www.diysolarforum.com Check out my best-selling, beginner-friendly 12V off-grid solar book (affiliate link): amzn.to/2Aj4dX4 If DIY is not for you, but you love solar and need an offgrid system, check out Tesla Solar. Low prices and great warranty, and they can take your entire house offgrid with their new Powerwalls: ts.la/william57509 ~~~~~~~~~~~~~~~~~~~~~~~~~ My solar equipment recommendations (Constantly updated! 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I have now watched the video. Surge protection is a wonderful idea on the DC side - do not oversize it, match it closely to the maximum open-circuit potential of the solar array. Get the ground connection wired as straight as possible to a good earth ground (and this can be separate from the service entrance - like at a ground-mounted array) but bonded to other ground rods if inside a structure. You are correct in not adding more ground points than at the service entrance of a building. Ground loops are to be avoided, chased down, and eradicated. They can cause all kinds of obscure issues. An SPD will not cause a ground loop. The DC side, being under 60 volts, is likely going to be a Class 2 circuit under the National Electrical Code (NEC) Solar arrays have the advantage of being inherently current-limited. Batteries are not, so over-current protection is required. Neither are going to be much of a shock hazard at 48 VDC. thanks!

I'm just a layman on the subject but I'm glad your warning people about adding extra grounds. The grounds all have to be bonded together at the same potential otherwise you are giving lightning a dangerous path through your home. Edit: also ground bonds need very heavy wire or flashing and short runs to be effective from my understanding.

Great videos, I learn a lot. Grounding is a complex topic. I don't have the answers but I have some thoughts. NEC 250.32 deals with grounding outbuildings. Since 2008, grounding electrodes are required at outbuildings like your garage causing multiple earth grounding electrodes contrary to the older philosophy of avoiding ground loops in the grounding conductor systems.

Great job explaining the shock hazard. Also GFIC breakers are a great way to save your life. All my shop outlets are fed buy GFIC breaker.

Good information. Appears that sub panels need to have isolated neutrals so faults go back to main panel. Grounding electrodes for lighting protection.

I built my own system and I’m totally confused, it always works better when you show exactly how you’re hooking up a ground and where and why! 😳 I’ll definitely look into the links. Thanks

Please do a video on grounding considerations for solar panels on both roof mounted and ground mounted arrays.

Perfect!!! If anyone disagrees with anything he said here go back and listen to it over and over and then study electrical engineering and electrical theory and you will then understand that everything that was said is spot on. Thank you Will.

I love it that you read and understand the manual. That's distressingly rare.

I am confused. A diagram would have been nice to include in the video. The lightning diagram alone taught me a lot!

Great presentation and explanation! Keep up the great work and posting videos you're saving equipment and you're definitely saving people for some nasty shocks.

Excellent! I feel slightly responsible! Something I didn't realize when watching other vidy (off grid title?) that you had an earth ground elsewhere. Absolutely correct, grounds loops are dangerous and can cause electrical problems with certain equipment. Bottom line, follow local code, mfg instructions. Any exposed conductive surfaces that encloses a potential (voltage) should be PROPERLY grounded to prevent shock. exceptions like double insulated code etc, ya need to check code. And yea, seen double insulated fail. And my apologies, didn't realize you DID have a proper grounded case (breaker box) enclosure.... thought off grid. Thanks, Ken

You do a very good presentation on all of your videos keep up the good work thanks..👍👍

I've never analyzed the grounding like you. But I've just followed the instructions. But I have thought about adding another grounding rod.

Excellent, and I fully agree (see 0:50). Approx quote: Even if you have two or three Grounding Electrodes you want to tie it together at one place'. Many absolutely stand by the fact that there can only be ONE Grounding Electrode period! They have no understanding of what Single-Point Grounding actually means! Many even think grounding attracts lightning which is directly opposed to sound engineering practices.

You are absolutely correct..!! It is clear you either studied your ass off self-taught or took engineering because you're always spot on!

Dude ur channel Came on my recommendation, glad i found...ur videos are awsome and well explained..

@will do more grounding vidoes. Start from the beginning. Been searching so few videos on this.

One more thing you need to understand about AC grounding is "Bonding" this provides a path for the electricity to trip the breakers from a grounded short circuit. Bonding is usually provided by a ribbon in the back of your breaker box that goes from ground to neutral. If you have multiple boxes, only bond your ground to the neutral in the box closes to the incoming service and remove the bonding connection in all boxes feeding the main box. Make sure grounds are in place to all wiring to other boxes. This provides only one path for a large surge or lightning.

William you are so informed thank you

Can you make a for dummies version of this.

On the subject of grounding. I have seen varying opinions on whether or not to ground the PV Array (I mean the PV frame NOT ground to inverters etc.) to Earth Grounding rod. You may want to do a video on this.

I think I need to revisit my ground setup. Thanks Will.

On my steel boat, I have a separate 24V lithium battery just connected to my mpp 3k inverter charger. I run the DC bus floating, with a 1 meg ohm resistor between the minus and the central grounding point. This way, I have the added safety of a floating system, and prevent static charge from building up on my DC bus. All Protective Earth conductors end in a central grounding point connected to the hull, just behind the isolation transformer. Shore power Earth is connected to a parking connection on the isolation transformer. When the boat is on the hard the shore power earth must be connected to the hull to prevent having a large steel structure that is unbonded. Marine Electrics in a Nutshell.

A local grounding to your own earth spike would make sense in case of an outage of commercial power, which would cause you to lose their ground reference. But in such a case, you’d also need to have an Earth-Neutral Bridge (the single point where it’s all bonded), which flips automatically between commercial power ground and your own local ground, depending on if the commercial provider is up or down. Surge protection on for each fuse box on the PV side is definitely a plus. I use 500V SPD’s.

Excellent points, however, in places as Florida which has more than a million lightning strikes yearly it is very important to have lightning dissipators the bigger and more the better to make the system invisible to electrons Flying in both directions.

It's amazing to me how many people misunderstand the purpose of earth ground. Mostly people seem to think that earth ground protects them from getting shocked somehow. Lack of "earth" ground doesn't mean you don't have a ground at all, it's just not tied to earth. Your ground wire still acts as an emergency return path to the breaker box to trip the circuit breaker if needed, but that ground wire doesn't need to be tied to earth to perform that duty. By not having an earth ground you're actually decreasing the chance of being shocked. Since the "earth" you're standing on is no longer a conductor you can no longer get shocked by simply accidentally touching a hot wire because there is no "return path" through the earth for that current to flow through your body. In fact: a common piece of safety equipment used by crews working in outdoor / wet environments is something called an "isolation transformer". It's a 1:1 transformer (So it doesn't step up or down) that plugs into a wall socket and creates a new electrical connection that creates an "isolated" electrical path that is no longer referenced to ground. This is used as a piece of safety equipment because by removing the earth ground as a return path for the current it makes it safer to use electrical equipment outdoors in wet conditions. Off grid inverters achieve the same result as an isolation transformer. They effectively "isolate" the electrical system from earth.

Will, be very careful discussing marine "grounding" as it can get tricky and lead to ALOT of corrosion for any metal touching the water. Stray current for marine is a big deal.

I agree with you on grounding. My car doesn't have a earth ground yet has a large power inverter

I swear you’re reading my search history. I was just looking up how to ground these systems

You are a wealth of knowledge in solar generation systems. However, this video was like another language. I’m sure the more advanced people could follow all you said. Me, not so much. I do understand ground to some degree. I understand how earth ground rods and such work with AC electricity. I was looking for help with the correct way to protect my small 4 panel system. My concerns are lighting protection for the panels. How and if I need to ground the wiring. How to connect my inverter to ground. That sort of thing. I will search your other videos. Thank you….

I've never been more confused about grounding and bonding after stopping here.

Code requires separate grounding electrodes for sub panels in outbuildings. You bring across 4 wires from the primary panel to the sub (L1, L2, N, GND), and you do not bond GND to N at the subpanel. That is to avoid current loops. But the remote subpanel DOES get it's own grounding electrode which is then connected to the ground bus bar in the sub panel and the ground pulled from the primary. A subpanel adjacent to the primary panel does not require its own grounding electrode, because the path to the primary is so short. So the question here is how far away is that sub panel from the primary. Even IF in the same building.

Extremely clear and concise. Thanks again for sharing. Have a great week.

I haven't watched the video yet. 1. *Lightning protection.* a system is more likely to survive if it is isolated from ground. 2. *Safety Ground* The protections of grounding an appliance chassis can now be handled by the newer technology of a Ground Fault Circuit Interrupter (GFCI). I will not be grounding my system, as any 120VAC load will run through some type of GFCI. I do the same for portable engine/generator sets. If anyone's system is to be installed permanently on a structure, building codes may apply depending on the jurisdiction. Your Authority Having Jurisdiction (AHJ) trumps anything I just said.

Hello Will, I have just discovered your videos and will be devouring them over the next while. Thank you for posting them! I have a situation that as a non - electrician has me confused, and I am hoping maybe you might have an answer for me. I am currently in the California desert in my solar powered cargo trailer/RV conversion. I am an astrophotographer, and spend my winter far out in the desert looking for dark skies. I have 4-325 watt Panasonic solar panels on the roof and 3-300 amp hour Lifeblue batteries for 900 watts total. The charge controller is a Midnight 150, and the charger/inverter is a Magnum 2000. The system was originally installed in my 5th wheel RV about 6 years ago by a very reputable solar company that specialized in RV installations. They have moved on and no longer do installations on RVs, so I can't talk to the people who actually installed it. I recently moved the solar system from the 5th wheel RV to the current cargo trailer/RV conversion. Grounding to earth in an RV is not practical of course, and nothing on the solar system has been grounded to the frame. I had read that the panel, inverter, and charge controller should all be grounded to the frame, yet they weren't by the original installers. The team that installed my system had installed solar systems in about 3000 other RVs before mine, so I doubt if they just "forgot" to ground the solar components to the frame. I have to think it was intentional. So when I moved the system to the current trailer, I didn't ground anything either. So far all is working great, with 4 120 volt and 4 12 volt circuits. Only the fridge 120 volt circuit is not on a GFCI. My 120 volt Samsung home fridge specifically says not to put it on a GFCI protected circuit. So my question is probably obvious: Should I be grounding anything to the frame of the RV? I used all metal outlet boxes, and they are all on internal walls. The outlet, and the box itself are grounded with a pigtail to the ground wire that goes back to the panel. As a non - electrician, I have a hard time understanding why I would ever want to send electricity into the metal frame of an RV. This seems crazy to me, and a recipe for a serious shock. It seems like I now have a closed electrical loop with the panel. Why would I want to send electricity to the frame of the RV, under any circumstances? As an aside, when I was a kid I stepped off a poorly grounded RV just after the rain had stopped. The step was metal, and I was barefoot and wet. I can only remember screaming and being frozen in place for a second or two before passing out and fortunately falling away from the step and breaking the ground. For a few hours I couldn't walk, and both my ankles were really sore. Within a few more hours I was fine. I suspect it would have killed me in a few more seconds if I had not passed out and broken the connection. It was a really terrible experience, and I don't want to relive it because I made a grounding error. But intentionally sending electricity into the RV frame just seems like the last thing I would want to do. Isn't an electrified RV frame what shocked me in the first place? Any advice much appreciated!

I agree completely, but I heard rumors for questionable sources that a Tesla charger might be very finicky in this type of circut. I was hoping to see how that worked out today. Great tutorial thanks.

Been there done that! Cleaning rack mounted equipment and bumped the conduit with my hand and damp rag while my neck was touching the earth grounded rack = a very big shock! (220v 50Hz) Burned my neck and locked me up until my coworker bumped me with his foot to break my neck from the rack. Turned out during install the power wire had the insulation skinned while being pulled through the conduit. 🥵

Unless you are using a single load against inverter, you want to have everything properly grounded possibly with GFCI. Otherwise a fault somewhere can cause ground loop and what would be grounded is e.g. a hot wire - then all what should be ground is suddenly "hot" against the earth, and this becomes a very dangerous setup. This is not a theoretical example, I touched a place which should be true ground on friend's off-grid powered house, then kept swearing for several minutes, then spend hours to debug how the hot wire got shorted to the ground - the root cause was a mouse chewing the wire insulation, where the wire came to contact with steel rod to basement, and so far, all ground over the house was suddenly hot against the earth.

When I was on the ANSI Residential/Commercial swimming pool and spa standards writing committees for a decade, we had this debate with building officials across the country. The NEC code forbids two grounds in the system for exactly the reason you described. With that said, many building officials force people to drive grounding rods at the pump pad. This creates exactly the system you describe and dumps stray voltage into the pool. What they are often trying to address (particularly with concrete shell pools) is that concrete and the steel rebar can pick up stray current from aging buried lines and this is detected when one grabs a handrail or sits on a wet deck with feet in water. It can be amplified in higher electrolyte pools (salt-based chlorination). In fiberglass/vinyl shells they are somewhat isolated just as you are describing in the DC/AC system (for different reasons, but conceptual similar). The shells are insulators and then they are forced by poorly written code to tie the ladder/handrails to the rebar in the deck. When metal cased lights where dominate, they could carry current into water, but in fiber optic one Is completely isolated in the pool unless a path is given back to the system ground. Although you are at the same potential as the deck, you still can become a bath to ground if it leaks in elsewhere. This isn’t completely related, but it’s so encouraging to see you continue to challenge status quo on what is often “telephone game” engineering.

Bonding Will, everything that is not the earth connection is a bond, not a ground. We use grounded bus bar in large incoming, high voltage vaults, as well as places like server roms to bond equipment to earth.

The NEC requires you to bind neutral and ground on the secondary of a separately derived system (transformers, solid state inverters, etc.). The reason for this is because the primary and secondary are physically separated, therefore the grounding connection does not transfer. You should bind the primary and secondary grounds (exclude the primary neutral because it is bound with the ground upstream).

Once again, awesome information, Will! You quite adeptly answered my question on your previous video. Looking forward to learning more about earth grounding and bonding to neutral situations for off grid systems.

We have a old lead acid off grid system. Way before all this new stuff. Just had a lightning bolt fry our inverter last night. Guess it's time to switch over!

Title says does my “offgrid” need a ground but you are saying it has ac input. What if there is no ac grid input then what?

Thanks Will, I applaud your thinking outside the box, making important points and challenging others to dialogue. I suspect however that many without a good understanding of the physics and dynamics involved many may not take to time to understand and consider the importance of what you have presented. Obviously you've taken the time to understand the big picture in theory and practice, and while I don't have as much experience with PV systems I much agree with and respect what you have presented here, and I believe there are other additional potential issues and dynamics to consider, and as such, I think i would be helpful to go into a bit more detail about the differences between service grounds, equipment grounds, bonding of service and equipment grounds, and a bit more for how SPD relate. Perhaps going through sections of the NEC on Service and equipment grounding and PV system grounding could help others to understand and implement what's in the NEC As an Industrial Wireman (Journeyman Electrician), an Electrical Administrator and project engineer on various industrial and petrol-chemical construction projects and facilities both onshore and offshore and specialized in power generation, grounding and control systems. During that time I observed that while often Code and convention were typically adequate as best practices I encountered many unique instances where "Proper" grounding was inadequate or created issues, especially in the case of grounding electrodes, ground grids, static and lightning strikes. In places where you have low and high soil conductivity such as in the Arctic were you are setting on frozen tundra, lighting doesn't dissipate through the earth very well we installed underground ground grids and 40ft grounding rod arrays, and very large underground copper grounding conductors to attempt to bond all buildings on the same service at the same earth ground potential and give lightning a path to dissipate to earth and prevent different lightning potentials between buildings that contained millions of dollars of electrical and electronic equipment, but during one unusually large electrical storm that in some locations proved inadequate for very large strikes. In the case of lighting strikes, SPDs might be inadequate depending on capacity of the SPDs and the quality of the earth ground they are attached to dissipate a large and direct lightning strike. In some areas prone to especially large lightning strikes, things like lightning arrestor systems and rods for PV arrays and premises may be a reasonable precaution.

Technically one grounding rod will not comply with NEC. You can have many as long as they tied together.

I spy with my little eye... some new Bluetti cables to the bottom right... excited to see your take on what they're up to.

If you wanted to add a 240v shock prevention device, look into adding a residual voltage device (RVD)

The larger the connector cable to the source from the output board, the smaller the earth fault loop impedance, making it trigger faster under fault conditions. You are correct, you wouldn't want to connect to a house earth system, some (most) do not have sufficient equipotential bonding and this allows for transient currents on the earth conductor, and we are not just talking milliamps.

You should use wiring diagrams when discussing this subject

I'm looking to disconnect my utility and have an inverter run my house, the inverter has the earth and neutral bonded at its output, i would like to run the inverter inplace of utility at the panel so would i have to remove the ground rod? It's confusing me.

I have a Xantrex Freedom Sw 3012 inverter charger, 4-6 volt batteries and two 160 watt solar panels. How much more solar power can I add to this setup. Thanks and Keep up the great work.

Its code to bond all electrical equipment including what you have there. Yes you should have only 1 point of ground but everything is required to be bonded.

I can see adding a ground rod only if this is for an off grid 120VAC or a 120/240VAC system. In this case, it would be the only ground rod. Otherwise, you are correct, 1 ground rod at the service entrance only when connected to a grid-tie system. But, what if you are using a 120VAC inverter in combination with a relay that redirects the load back to grid when the inverter turns off? The grid side is grounded, but the inverter side would not be. I have several of these systems, and I tied all my grounds together on each one. This grounds the inverter cases and the inverter output.

Absolutely you never want two earth ground with one system for the ground loop reasons you stated. I did not realize you had an AC input from your house. Many inverters will bond the neutral to the input AC when they switch to line power. Does the AC input ground common to your solar ground? If so you may want on oversized ground wire back to your house and it’s ground rode. Thanks again for your great videos.

I just purchased Will's Mobile Solar book. I like it but the very small font size makes it very difficult to read for my old eyes.

One thing to always consider if isolating, is peripheral equipment ground (accidentally or otherwise). Just an AC unit sitting on a poured pad gets a surprising amount of earth ground into the housing.

Please provide some visualization on this topic. I have seen an end to end Inverter/Electric Sub-panel/Battery setup video and the gentleman there grounded the whole system with a true grounding electrode. Basically a separate grounding bus bar in the subpanel which is connected to inverters as well as true ground electrode outside.

Would like for you to test or give your opinion on the EMP Shield product to protect your equipment from pulse power surges.

I just wish the pv inputs would not have dangerous AC voltage coming from the pv inputs on both positive and negative to earth ground.. I was "shocked" to find this on the pv input without the panels connected yet... also, fun fact.. between the 2 pv input negatives or the 2 pv input positives from the the 2 different inverters yields approximately 350 AC voltage.

You are conflating neutral bonding with grounding. The neutral is bonded to ground at ONE point only. Ground does not carry ANY current when done properly and there is no limit to it's attachment to earth. For example, all metal within 5' of water is required to be electrically bonded to earth, a/k/a ground. This includes rebar, plumbing, metal framing, windows, doors, screen enclosures, etc. Some of these items, such as copper pipe and rebar, may be buried in the earth and serve as a ground path. Again, there is no limit to points of contact with earth for bonding and more is better, but all of them MUST be tied together. This is all covered in the NEC manual which you are required to comply with.

You can have multiple ground rods as long as they are all connected with heavy wire (6 AWG) or copper strap. That will eliminate any voltage potential between the separate circuits they are connected to. Eight ft. rods should be spaced 16 ft. apart.

Good explanation.

My growatt inverter specifically addresses this in the manual where I have to have an inverter controlled relay to bond and unbound my ground to neutral on the inverter output specifically when it switches back to grid power. Perhaps you can do a video on this?

This now raises my own questions. Is it possible I can send you a YT link to a video of my setup with my current ground configuration, get your feed back?

Seems a bit over complicated ... my understanding of what I think I heard ... a panelboard/breaker box (out of your inverter) should always be tied to an earth ground. You may choose to earth ground the metal case of your outdoor solar panels for lightning protection. However, do not earth ground your solar panel output/PV supply to your charge controller. It's okay to surge protect the PV supply, but again, do not earth ground it. Is that accurate?

May sound stupid but someone could ground this system using a low resistance power resistor as a shunt system, so as to not cause the inverter a complete short circuit and blow mosfets but make it possible to have a return ground path in case a short happens in the device or local code demands you ground the system. The other option is a seperate ground with no bonded neutral just to dissipate static buildup.

Lightning protection is best done via lightning rods, which have their own dedicated earthing conductors not to be shared with anything, as the lightning will travel down it, which then yes produces a gradient voltage across anything it touches, including dirt. The house grid earth connection is there in case the earth connection at the pole transformer is lost, the connection to earth is maintained, via the bonded neutral (both at the pole transformer and the house mains panel). The neutral-to-ground "bond" is there for fault current to travel back up the neutral to the power source, tripping the circuit breaker on the hot controlled conductor. This conductor is the ground pin on a wallsocket, it also neutralizes the live voltage during a fault so that humans don't get shocked. Some SPD's just happen to use one or both to achieve surge dissipation, which is fine. The neutral should only ever conduct the operational current, which is also flows back to the power source tripping the breaker during normal operation. It may or may not also conduct fault current by happenstance. There should only be one earth connection point and the ground should never be used to carry any operational current, this also prevents voltage gradients from damaging equipment. If you have properly installed lightning rods there shouldn't be a need for array SPD's, other than perhaps static discharge. A direct hit will render just about anything dead regardless of how good the SPD is designed or believed to be. Some inverters are single phase, some are split-phase, some have bonded neutral and some don't, all of which adds extra complexity for DIY'ers. If anyone is unsure then they should just contact a certified electrician to do the work, it might save their life and/or not burn their whole city to the ground. (and code compliance and all.)

Really falling off that cliff of the Dunning Kruger effect curve if you know what I mean. I guess that’s progress…

Should there be a neutral to ground bond screw in the sub panel box or no ?

Very interesting stuff about the "ground loop". And I have a question. My house has a ground for the sockets (with those metal rods in the ground at the corner of the house) and a separate ground (another metal bar at the opposite corner of the house, as it happens...) for the tv cable. Is that wrong? I am assuming the shield on the antenna plug at the tv is connected to the power ground. Maybe not. Am I in danger? Thanks!

2000w SunGoldPower inverter charger fed from my house 120v, and from 3 X 100w solar panels. All feeding 4 X 100ah LiFePo4 batteries. House is earth grounded. What I hear you saying is that I should remove my earth ground on my solar panels ASAP?

Thank you sir

I see licensed electricians arguing about proper grounding most every day on Reddit. It’s a tricky point, but I think you are accurate, Will.

In Europe we run a true earth most times as an IT-System is too expensive. You don't need a insulation monitoring system. A small cable from a charger isn't a grounding for a 13kW System. The danger comes with grounding as each and every wire carries a little bit of true ground from the earth (induction grounding, resistive grounding, capacitive grounding). If the wires are to long: you still have a ground loop. You should no exceed 15mA to true ground and every appliance should work without earthing (some needs earthing and some not). Every appliance with an y-capacitor (EMI-filter) needs a true ground to earth. A common way is to bond all grounds in you house together and run a big wire from this ground to you solar system.

I do have my panels on their own grounding for the panel frames and dc lines are fused incase something tries to send more amps through the dc input lines like a failed shorting inverter that backfeds ac to the panel frames.

I appreciate this info. I'm 100%off grid and I was curious if I should have a earth ground connected. I bought a grounding rod but have never hooked it up. I felt like it was a complete closed system and didn't believe I actually needed one.. I have a 5kw eco-worthy hybrid inverter. Connected to my camper breaker box. I also have a inverter generator hooked up to my system to charge/bypass also I have 12 solar panels.. so... Should I use my ground rod?? Thank you

Are you sure connecting neutral and ground and the panel is correct? Assuming they are separate: If a ground fault occured in equipment powered by this system (current flowing from the AC hot leg to equipment ground), the current would have to flow through the inverter on the ground wire, but the inverter will shut the system down instead.

I'd like to see a video on the pv power disapation.

Dude you are baller. You should seriously be a college professor. The garbage that people “learn” in school blows my mind. You are clear, concise, genuine, and factual. Bravo. Oh and I had to chuckle every time you said SBD 💨 Be well man!

what about the panels? should they be grounded and bonded to each other? ( the framing)

Hi there, thanks, please connect ac input (utility power), and make a video to us....very nice..keep going.

Will, Great point. A similar question relating to those solar generator/power stations. I believe they are not truly grounded. The A/C output runs on floating neutral. What if, when the A/C charge input is connected. Would the power station be grounded during the time through the A/C input cable? Now, would the ground pass through to the A/C output if there were output load plugged in the A/C output jack?

I'm not sure how you run ground in the states, but the ground we use if for fault current return and has nothing to due with lightning strikes, that's what lightning arrestors are for. In most cases using the M.E.N. system (multiple earth neutral), the main earth is tied into the neutral conductor. Any metallic enclosure has to be earthed so that if a fault occurs with an active conductor to frame it will trip the circuit breaker, and any fault that occurs through a person to ground trips the R.C.D. (residual current device). However having said that we also have other earthing systems other than M.E.N. such as the Direct Earthing System, The E.L.C.B. System (Earth Leakage Circuit Breaker) (voltage operated type), and the S.W.E.R. (Single Wire Earth Return) that uses only one wire and the ground is the neutral return system. I found what you were trying to say a little confusing but that may be attributed to different terminology used. But basically yes, the earthing conductor is used for return fault currents and has nothing to do with lightning. Our supply authorities use a three phase system for reticulation and distribution, generally delta to star step down transformers where the centre point of the star connection is the neutral connection which can also be earthed. Nice watching albeit a little confusing.

Will, your title indicates this video is about OFF GRID SYSTEMS ONLY yet you continually talk about AC inputs. If you have AC inputs then it is not off grid. How about another video about true off grid systems with NO AC input at all.

Hey Will. Very informative videos! I’ve watched many of your videos on lithium batteries but I wondered if you have reviewed later generation lead acid batteries called crystal lead batteries? Not as good as LiFePO4 but reportedly much improved on flooded lead acid batteries. Could they be a low budget option worth considering?

Earth bonding for casing that's what we call it over the pond.

Very helpful.

Great video, but I had a question about these inverters. I went on their website and found that these are “off grid” inverters. What is this “AC input” that you refer to in your video? Is that for AC charging?