Where Does Grounded Electricity Actually Go?

[@PracticalEngineeringChannel]

📖Did you know I wrote a book with a whole illustrated chapter on the power grid? store.practical.engineering/ 🥑 For 50% off with HelloFresh PLUS free shipping, use code 50PRACTICAL at bit.ly/44zdZll!

[@amschelco.1434]

Great channel very very well explained sir!

[@TheRegulator]

Got the book and I love it. It is the perfect coffee table book. Also... that Henson razor is a game changer. I love it.

[@rockets4kids]

It would have helped if you spent a bit more time explaining how three-phase AC power works. You glossed over that so quickly I bet most people completely missed the most critical issues here. I'll admit this is something that could take a video all on its own to explain properly, so go do that!

[@KihoroWamahiu]

Hi, Does Hello Fresh Ship To Outside The US? Say To Kenya?🇰🇪 Avid Fan From Kenya 🖐

[@Stacy_Smith]

I think Hulk Hogan messed around with Zap's mom. There's a striking resemblance.

[@user-Adam72]

@Practical Engineering: at approx 19:30 you mention hopping to limit the chance of step potential - this is no longer the case, at least in the Australian electricity industry. The reason is that a person hopping (one or 2 footed) is very prone to overbalance and accidentelly step or fall, thereby creating the step potential and possibly injuring themeselves as well. Current training is to keep both feet together and 'shuffle' by sliding one foot forward no more than 3/4 of the length of the foot so they stay together, then shifting the other foot in the same manner. In this way, while some 'step potential' will potentially still exist it will be small, and the feet / ankles / legs touching provides a path for any currect without transitting through the torso. Another thing to note is to avoid any sudden ground condition changes where possible - don't move from dry ground to wet, concrete to grass, etc. Great content!

[@user-Adam72]

For anyone interested in the real life consequences of poor grounding and floating Neutral wires, here is a link to an incident in New South Wales, Australia in 2014. The report is quite a detailed investigation and highlights what this video is discussing quite well. www.resourcesregulator.nsw.gov.au/sites/default/files/documents/iir15-01-fatality-at-house-near-quarry.pdf

[@blueberry1c2]

Not from the electrical service industry but I was taught another (still different) way of getting away from ground potential: short hopping with both feet together

[@WanJae42]

That's recommended in electrical training in the US, too. (At least what I had.)

[@anwyl42]

could you attach a wire to the boots, running along the pants to give a lower resistance path?

[@StephenGillie]

@@anwyl42 Exactly what I was thinking - can't we just "ground" the shoes to each other?

[@zzzz271]

I am an electrical engineer (in the US) that designs the grounding grids for substations to limit touch and step potentials. I can confirm that there are tons of calculations & analyses that go into the design, including simulations of worst case faults to make sure there is a near zero chance of injury. However, ground grids are not designed to eliminate potentials, only to reduce it enough to prevent arrhythmia. So if you happen to be at a substation during a ground fault, you may still get zapped, but it won't be fatal! Great video Grady!

[@BTW...]

What is the typical voltage potential at these subs? An even more difficult concept for many here to understand is Prospective Instantaneous Fault Current.

[@dmsdmullins]

How many people do you know who have, "shuffled to safety". I bet it's zero.

[@brockolious]

That's so cool, @zzzz271! I was always amazed to see how much detail, planning, and regulations/standards you have to adhere to with substation grounding grid analysis and recommendations, just to make sure any human life inside and slightly near the fence line has a chance to survive if a fault occurs. It's so much more than just welding a bunch of copper grounding grid into the earth and saying "done!"

[@MojashYT]

@@BTW... Earth Potential Rise (EPR) can vary anywhere from 100 V to over 10 kV. Both have the prospect of being fatal, depending on the scenario, and how it has been designed. There is a huge amount of risk analysis that goes into the mathematical calcs to ensure highest probable safety.

[@Lucas-ry7dd]

nice

[@ElectroBOOM]

Well done! You stepped in my territory, and you managed to survive! 😁

[@tytytyy10]

Ahhh!! I love this! This is hilarious

[@ibtidaahmed9684]

Yeah! He was on the safe side and did make a really good explanation video.

[@Red-ding-Ton]

Hi mate how are you?

[@jamesmorriss9565]

If you were there Grady would have been cleaning for hours to get the sand off the floor... and the walls, the ceiling, and....

[@PracticalEngineeringChannel]

I was tempted to leave in some inaccuracies to try to start another KZbin EE debate!

[@FanZ2626]

I never felt like the concept of electrical ground was very well explained in any of my electronics or physics classes; and I still don't feel like I totally understand it, but this video helped at least a little bit, so thanks!

[@ronjones-6977]

It's magic and I don't care... until it stops.

[@alfredopampanga9356]

Yes, he actually isn’t good at explaining things

[@alfredopampanga9356]

@@jimleigh7781 When someone is not good at explaining something it’s often because they don’t fully understand it themselves.

[@Khulu6061]

Haha, you caught him😂​@@alfredopampanga9356

[@chrisharris6462]

I gather thatground is the place where e- dissipates in multiple ways. Also, e- can flow out of the ground to a generator to produce power?! 17:42

[@sheepiscool]

it goes into the ground

[@windowsxpmemesandstufflol]

I can't believe it

[@AmirDarkOne]

don't believe it russian misinformation

[@missaisohee]

i see, thanks

[@interstellarsurfer]

​@@GOOD_FARMERYes, the ground is made of ground. 👍

[@gamemeister27]

​@@interstellarsurferNo it's made of earth

[@Danger_mouse]

13:00 Grady, fun fact. The early telegraph system in outback Australia used a single wire system as the iron ore content in the soil was high enough to use as the earth return. It's what gives the outback the classic red/orange colour.

[@Liveleadplayer70]

i think i saw snippets of Australia in this video tbh..looked like home to me

[@nigelhungerford-symes5059]

​@@Liveleadplayer70 yep we have SWER in parts.

[@declanclaus6681]

Australia is the mars of earth

[@mrx6682]

yes I'm an Australian electrician. This is called SWER and it still exists

[@robertagostino629]

Woah. That’s so cool

[@BluesMan1234]

As an electrician I see a lot of apprentices get confused with grounding, grounded and bonding. In school and generally out in the world we hear a lot of "electricity wants to flow to ground" without really understanding whats happening. Easiest way I explain it, electricity doesn't want to flow to ground, it wants to return to the source, through the ground, in a grounded and properly bonded system.

[@whuzzzup]

That is a good explanation because this way it's very easy to see that there won't be any electricity flowing from the battery to the earth.

[@Bacongrease00]

Whatever leaves the source must return to the source

[@nicolasjonasson4820]

Call it return path instead of ground and it will make a little more sense.

[@AdamYakan]

kzbin.info/www/bejne/oIPckIywq6mpa7M

[@AdamYakan]

kzbin.info/www/bejne/oIPckIywq6mpa7M

[@traildude7538]

I helped an electrician completely overhaul the electrical system at a large multi-building facility originally built in 1906. All the lines in on building were just single wires that ran the length of the building and at the far end connected to a steel pipe that ran along the top of the wall; that was the return line. We made a bizarre discovery, though: the men's restroom in one corner of the building still had the old steel trough as a common urinal, which was bolted to a frame of steel pipe inside the wall. Somewhere in the decades between the original construction and the electrical overhaul, for some reason the steel pipe serving as the return electrical line had been cut and a section removed -- and when that section had been replaced it hadn't gotten connected back to the return line but instead to the steel frame for that trough urinal, and then a heavy wire had been run from that frame back to the main electrical panel. So for years, probably decades, that men's restroom had an electrified urinal. BTW, the 'hot' wires were only insulated on about eight inches on either side of where they were attached to glass mounting insulators, and the wire insulation was just tar paper wrapped around the copper wire.

[@soaringvulture]

A hot urinal trough has the potential (see what I did?) to cause serious injury if the bathroom floor is somewhat conductive, like from being wet. It's similar to pissing on the third rail.

[@traildude7538]

@@soaringvulture Cute pun. We figured either people had been very lucky or there was a shorter path to ground somewhere, or the steel urinal was itself grounded well. The general manager wasn't interested in paying what it would have cost to trace things to find out, though, so we just did the overhaul and made sure the electrical system was no longer using any connections to plumbing as a ground. Later when a plumber was dealing with an issue not even twenty feet from that restroom I mentioned the electrical silliness, so we traced pipe, ended up pulling sixty feet or so that wasn't actually attached to any water lines plus used PVC sections to join lines on a couple of T-connectors so the only thing flowing would be water.

[@jeffreyyoung4104]

@@traildude7538 COLD water pipes were considered acceptable ground points for decades, but that is changing due to PVC and other plastics used in plumbing. Besides, having a solid wire from ground to point of use is much better than pipes with many joints!

[@googlem7]

Excellent

[@RedWolfenstein]

You'd be surprised how many electricians I work with think the neutral is always a non hot wire

[@rhouser1280]

When I started at the power plant, I asked about where all it fed power to. A guy told me it’s pretty much like throwing a cup of water in a stream & someone else pulling a cup of water out down stream. Yea it could’ve been your water, but more than likely, it was a combo of all the tributaries.

[@danpro4519]

So when we are billed to a single power company, how do they know how much of "their" power we actually used?

[@ethereous]

@@danpro4519 That has to do with distribution. Your local utility, co-op, or municipality was the one that installed all of the equipment in order to deliver you power, aka the feeders (power lines), the protection equipment, the substations, and more. They can generate power themselves, or they can purchase their power in order to deliver you yours.

[@HxTurtle]

@@danpro4519 that's not a question since both are entirely different entities. a power company is engaged in the field of producing electricity and then also in distributing it. those are separate things. with different revenue flows and balance sheets. more often then not, the distribution even inflicts an internal loss. meaning, would they just sell all their electricity to current brokers instead of the consumers, they'd be better off even.

[@imperatoriacustodum4667]

@@danpro4519 Here in the UK, power companies are meant to charge you based on grid usage rather than supply usage as the national grid controls the flow of the entire grid including from all sources, imports and everything. The engineer/TV presenter Guy Martin took over the national grid for a short time in learning how it all works in a series - "Guy Martin's Great British Power Trip" But, that's the UK, so I don't know how it works for others.

[@rhouser1280]

@@danpro4519 as far as generators are concerned. They just get a demand from the grid operators, & then try to meet that demand. Renewable & Fossil plants both put power onto the same grid, as the person above mentioned, it’s the transmission operators & distributor’s that actually deliver the power. Sometimes it’s all the same company but such as in my case, our plant is owned by a different company than the one that operates the grid. So customers pay them, & they keep some & pay us whatever the agreed upon price was per Megawatt when we produced it.

[@michaelcarr2466]

I'm in charge of a power transmission grid and always enjoy your videos. The accuracy of the information makes me trust your videos on topics for which I'm not an expert. Your channel is a gift to the world.

[@andreismirnov7200]

Hi man, in this case maybe you can help me with the question that has been bothering me for a long time - where does an extra current generated by a house solar panel go? It circulates in the local grid up to the transformator, right? It can not go up onto the high voltage grid, right?

[@michaelcarr2466]

@@andreismirnov7200 it can go up into the high voltage grid if you were to make enough. We have a solar installation not unlike a home installation, but a bit larger at around 500kW. It goes through the 11kV to 415V transformer, thus feeding the local medium voltage grid. Yours is likely flowing to your neighbors, but if you're on your own transformer, it's also getting there on the medium voltage grid. But like this video says, it's not practical to tell which current comes from where exactly. It flows where it can based on impedances.

[@andreismirnov7200]

@@michaelcarr2466 first of all, big thanks for your professional opinion! So, transformers work both ways without limitations, so all theoretic excess electricity can go up the grid? I was asking more about regular home solar installations, all big solar farms probably a totally different story. My big problem with solar is that nobody knows if any of this excess electricity generated in the summer is needed, to what extent and how it is used. It is generated and just "goes somewhere". In the winter everybody still gets power from grid and consumer is stuck with the bill for all these solar experiments that nobody knows economics of.

[@michaelcarr2466]

@@andreismirnov7200 You are correct; transformers work in both directions, and thus excess electricity would flow into the grid. You are also correct that the economics of residential solar installations can be complicated, and also result in unintended consequences. There are additional concerns regarding the reliability of the grid when solar and wind become a large portion of the supply, and more traditional generation goes offline. A traditional generator provides physical inertia to the grid which improves the grid stability.

[@andreismirnov7200]

@@michaelcarr2466 thank you very much again for your valuable clarifications and confirmations.

[@javersongoulartfilho9439]

As a chemist I'm used to deal with elements exchanging electrons to make things happen, but when it comes to electricity in a circuit & insulation I'm as a smart as a wood door, save from battery cells. Thanks for sharing this with us.

[@MR-nl8xr]

Glad to have a chemist in the room for once. While you are here, I have been meaning to ask if with the discovery of Quantum "Spin", have Chemists come up with anything in elemental electron exchange?

[@deelowe3]

I find all the analogies confusing. For me, electricity is easier to understand from first principles. Unfortunately, that involves quantum mechanics, which I guess many feel is too complicated to explain. But only after I saw some videos explaining that electricity is all about the movement of fields and not electrons flowing through the wire like little balls in a pipe, it all clicked. AC is extremely difficult for me to understand if I try to understand it using the traditional analogies.

[@Matthews_Resume]

I must suspect there are similarities. As I understand , in order for an electron to move to a higher orbit it needs to have 'enough energy'. An electron following its designed path would be the equivalent of a circuit. Insulation refers to the amount of 'enough energy' required to exceed its normal path to reach a higher orbit(s). To say, insulation=resistance, the distance of, 'enough energy', required to reach higher orbits becomes equivalent to the amount of insulation (resistance) that must be overcome. From Gradys sand example: dry sand offers the most insulation, wet sand offers an amount of insulation, yet salt water offers little insulation. (Different salt((s)) offers different abilities.)

[@javersongoulartfilho9439]

@@MR-nl8xr Honestly, after getting to know the basics of quantum in college I figured out it’s just too much for me. The probabilistic behavior of wave-particles in confined orbitals blows my mind every time I think of it, in the end always going back to physics and tons of math (which is a marvelous way to describe and understand reality). Channels like PBS Space Time, Veritassium, The Science Asylum, Physics Videos by Eugene, Arvin Ash and many others would give you a much better response to your question. As far as I know, genius scientists are using the quantum properties to improve computing power. I’m a simple man.

[@sciencebeing6134]

@@deelowe3 Can you suggest those videos.

[@johnstreet797]

Grady you do a fantastic job of education and explanation of your subjects. I lived in Cambodia which has a 220/380V or so system. Each house was connected to one hot leg of a 3 wire wye and the common. Common was NOT grounded. Middle of the night one phase was 280, in the heat of the day with all the air con running it was 160 or so. Across the street was a welding shop which was on a different hot leg of the wye. I has incandescent lights in my bathrooms, and whenever he struck an arc it would drag the common towards him and increase the brightness of my lamps A LOT. I finally replaced those fixtures with electronic ballast fluorescents, which eliminated the change in luminance. Some fluorescent light switches in the house broke the common instead of the hot, so the input capacitor in the ballast would charge and then flash the lamp about every 5 minutes. Interesting experience living there.

[@stephenalexander6721]

I worked as a journeyman lineman for 36 years. I have found your videos to be interesting and accurate. I think your comment about electricity following all the paths available is very important. Many have been killed thinking the the path of least resistance. I started in 72 and the rule then was to work "between grounds.". Time went by and "singlepoint' grounding became a thing. Grounding from the conductors to the tower or pole below the linemans feet making for no differential. It was a hard sell, still might be, but it works. Im going to watch this one a few more times to see if I can learn more. I think you are one of a few people, who sre not in the electrical industry, who understand what goes on here.

[@JonnyMack33]

What do mean by "between grounds".. and "singlepoint" ?

[@chriswebster24]

I was a defensive lineman when I was younger, but when I got to high school, I became a linebacker. I know what it’s like to be a lineman, though, so I can totally relate to what you do. It’s a tough job, for sure, but it’s a very important one. I’m sure your team appreciates all your hard work.

[@FrankBenlin]

"Im going to watch this one a few more times to see if I can learn more." Good. I was feeling very ignorant about electricity while thinking about how many times I will need to watch this. Thank you.

[@nancymatro8029]

obvious joke, silly @@chriswebster24

[@SodiumInduction-hv]

i’m an apprentice lineman

[@kvg4790]

My electronics professor was explaining 3 phase, 4 wire motors. He had a diagram of the 3phase generator connected to the 3phase motor and kept emphasizing the “4 wire” part of it. Finally a student asked, “where is the fourth wire?” Then he pointed to the ground symbol and added a ground layer to the diagram connecting the generator and the motor.

[@toddmarshall7573]

Three phase may be configured in a "Y" or "Delta" configuration. In Delta configuration there is no phase to neutral connection. At terminations a transformer makes the conversion Y to Delta or vice versa.

[@MR-nl8xr]

How long the class suffered trying to understand until one mind could not take it any longer and had to let his soul get satisfaction in answer form.

[@altuber99_athlete]

Technically, the term “three-phase four-wire” *never* refers to the use of a ground wire, only a neutral wire. If I have a three-phase motor that for some reasons used a neutral wire, as well as a ground wire, it is a four-wire grounded motor (not five-wire).

[@Majima_Nowhere]

​​@@MR-nl8xrOr he's trying to let students think for themselves instead of just blindly accepting everything he says. "Ah yes, three does equal four, because teacher says so." If using an ounce of brain power to ask why something seems wrong is considered "suffering," then it's no wonder our education system doesn't work.

[@danclason5389]

I would try and get students to understand the difference between a neutral and a ground before I got too far into a discussion . That would clear up the confusion. And I have been guilty of using one term when the other was correct.

[@alexanderthomas2660]

Great video. Despite having a degree in electrical engineering for 21 years, this is the first time someone completely explains the concept of ‘ground’ in all its aspects in one single go.

[@youtube_omaro1879]

Technically he explained earth, not ground, and got the two confused

[@sootikins]

@@youtube_omaro1879 Let me guess... European, right? In North America, the thing you guys call earth (the green wire, the spike into the dirt, etc.) is commonly called ground. So is the common/return/reference point in an electronic circuit. Yes this can lead to confusion.

[@sootikins]

Yeah, long time EE here too, and no I too was never taught much about grounding systems in school. I've been told they teach it in trade/tech schools. Or you learn it by working in for an electrical utility co. Actually very little of the knowledge I use to earn my living was taught in my "higher" education.

[@youtube_omaro1879]

@@sootikins Australian. But I learnt that nitpick off American textbooks, or at least I think I did. Circuit ground is not the same as the Earth. Perhaps this is a more Electronics than Electrical distinction, but I'm pretty sure that we always call our green wire earth too.

[@sootikins]

@@youtube_omaro1879 If I'm talking to an electrician I usually say "ground". But if I'm talking to an electronics person I try to say "earth ground" to avoid confusion with system ground aka common. Then there's stuff like servo controllers where you may have "analog ground" and "digital ground" and "ground " (aka protective earth) all on one unit - lol!

[@Niall16lennoN]

I work at an insurance company, and a major fire loss came in where the client had installed an electric fence on their balcony to ward off pigeons/birds, and it required grounding. They put the wire into a plant pot on their balcony.

[@h3069]

Really spices up the petunias

[@miketheperformer5972]

Now that's a bird brained set up.

[@koobs4549]

The bigger question is, did the claim get paid out?

[@buildingwhisper]

They were making a power plant

[@frostonium]

h@@buildingwhisperholyyy

[@FuncleChuck]

I like when ground is Earth. Grounding to the Moon is just so difficult.

[@kiriuxeosa8716]

You're just not using the right ladder

[@mickavoidant4780]

​@@kiriuxeosa8716It's a step ladder. The real one died.

[@sethproaps8899]

I wonder if the english artemis astronauts will call the 0v potential on base "mooning"

[@bag2963]

Smh... Words aren't toys.

[@danbert8]

Definitely need a bonding cable run at some point.

[@Zephyr77]

In the Navy even though it can be more dangerous, we often use ungrounded 3 phase distribution systems so that they continue operating even in the event of a ground fault (like a missile blows a hole in the side of the ship)

[@TCB2023.]

Really that's cool! Hawaii EJ

[@thatspsychotic]

This (ungrounded 3-phase delta) is also fairly common in industrial applications, especially for wet processes where ground faults could be common.

[@AdamYakan]

kzbin.info/www/bejne/oIPckIywq6mpa7M

[@rthony7780]

i think it is pretty common not only in the navy but most of merchant ships today just monitor ground fault and have an alarm system for it, instead of interrupting the service, in the power generating side however(in the generator) it is still necessary to monitor ground fault current

[@raynic1173]

I was a welder in the navy. Most of the time we only needed to carry/run one lead to the work area/parts, as the ship was the return path, AKA ground.

[@will75wallace]

My job has a high resistance ground on our 480v distribution system. It’s wild to realize one phase is at 0 volts during a fault and non of the equipment cares because phase to phase doesn’t change.

[@BTW...]

Yet 2 of those phases in such a fault condition will be much higher voltage to ground, easily exceeding the rated voltage of insulation. That high ground/Earth impedance is a matter that should be addressed.

[@onradioactivewaves]

​@@BTW...Is the wire only rated for 600V in these applications?

[@will75wallace]

@@BTW... the ungrounded phases go from 277 to 480 phase to ground and the phase to phase voltage is unaffected. Still below the common 600v rating of most insulation.

[@MrMaxyield]

Ah yes the high impedance grounded system. The Cadillac of electrical systems. Are you by any chance in a hospital...??

[@will75wallace]

@@MrMaxyield Glass plant. The furnace requires similar reliability to a hospital.

[@fayiznalu8411]

I am master electrician and I have watched your video more than once and everything l learned in the 20 plus years about grounding feel I have just started to understand abit more how grounding really works..! Very interesting and I will continue to follow practical engineering; thank you and Mike Holt as well for the email. God bless 🙏

[@shorttimer874]

In the sixties my dad was converting our house from a furnace, which at some time in the past had been modified from burning coal to oil, to electric baseboards. Part of the project also involved moving and updating the fuse box to circuit breakers. Dad worked for the local power company and got a former lineman, certified for such work, to come make the change over. He had lost the lower part of both arms in a work accident. I was young and fascinated and he did not mind showing me how the hooks split apart and closed using wires that were controlled by shoulder shrugs. I have been very, very careful around wiring ever since.

[@caravanlifenz]

A scaffolder in New Zealand recently lost both arms after the metal pole he was holding to assemble the scaffolding touched the overhead power lines. He spent 6 months in the burns unit recovering. Electricity is nasty stuff. It makes me think how lucky we all are that electrical tradespeople risk their lives at work so the rest of us can relax with electricity at home to watch TV and make coffee.

[@LordAJ12345]

As someone who has spent days in the field sticking electrodes in the ground for geoelectric measurements, I really appreciate the (saturated) sand experiment. It's a good visualisation of how applying voltage to the ground can be used to measure its conductivity and therefore draw conclusions about its composition.

[@ron6625]

As a surveyor who has asbuilt and checked ground rods/ground grids it also helps illustrate why I was correct to scold guys trying to put gravel in instead of washed/clear rock when they were going shallow with the ground grid. I've also done some line locating in the past too, and that principle works really well when doing line locating too. There was a really deep water line that had tracer line on it that was still not being located by most guys. I noticed a pond/big pool of water at the riser location where the pipe and tracer line came out of the ground. Instead of just using a spike to connect my negative lead, I just used a large steel tow rope, attached my lead to it and threw it in the pond. I found that line that 2 line locating companies (remind you, I'm a surveyor) spent two weeks not able to locate without much problem. That was pretty satisfying.

[@NoahSpurrier]

I remember working with a friend of mine on my home electrics. I mentioned to him that the circuit was live, so be careful. He said not to worry because he wasn’t grounded. He grabbed the hot wire and got a shock. I explained capacitive coupling with AC.

[@ianallen738]

"so be careful" would have been to have shut off the power before the circuit was exposed and a risk of shock was non negligible.

[@rambysophistry1220]

@@ianallen738 That only applies if the work can be done on a cold circuit. If they were troubleshooting a circuit, they might not be able to find the problem if it was cold. Sometimes hot work cannot be avoided, and so other methods have to be used to maintain safety.

[@NoahSpurrier]

@@ianallen738 We were just getting started. I did mention that the breaker wasn’t off. I wasn’t expecting anyone to work on a live circuit or anticipating anyone to reach in a grab the hot line after I warned that it was live.

[@Arkios64]

I literally have to double bag my hands in certain areas of my job because there's so much capacitive coupling that turning off the power INCREASES the voltage you can measure. It's wonderful every time, changing out an old light fixture and getting 300V+ not even 5 seconds after shorting all wires.

[@teardowndan5364]

The shock from capacitively-coupled mains and L-N/L-G mains are two completely different things though. The capacitively-coupled one (about 100pF of human body capacitance, 26Megohms at 60Hz), is only an unpleasant but otherwise harmless tingle while L-N/G is painfully sharp and potentially lethal. In both cases, I'm more worried about over-reacting to shocks than the shocks themselves on 120V.

[@holysol]

it goes to its room to think about what its done, only then can it have dinner

[@isaac1998]

HAHAHA

[@dustinsullivan7216]

Your tap water must be ridiculously good. At my high power lab, we would use city tap water as a salt water source when mixing into DI water to set water conductivity.

[@heftycat]

That must taste disgusting!! His water comes from the Edward's Aquifer...and it's taste is pretty good...but the city has added flouride like 20 years ago, and so now it's taste is only okay imo. (maybe it's in my head)

[@rodrigoalonsoparravicini937]

As an electrical engineer I've always seen your videos talking, most of the time, about civil's but with this video I'm really surprised, you've digged into one of the most unknown and hard to explain topics in the matter of power systems and made it really comprensive, which is not that easy. very nice work! PD:I see also that You have good food taste as well hahaha, try to make ceviche I think you have the skills for it!

[@omniyambot9876]

electrical engineer that considers grounding as one of the modt unknown😅

[@rodrigoalonsoparravicini937]

@@omniyambot9876 As is not part of the main topics, commonly is assumed and not deeply explained. Which is impresive because of the importance of the matter, maybe for an EE not but for some professionals of the sector.

[@MarioGoatse]

You’re a great teacher Grady. It’s crazy to think that you don’t have professional teaching experience. You’ve taught me so much about the world around me. From full sized dams, to weirs, and even the dynamics of water pipes. It’s amazing how much more interesting the world is when you know how it works. I really appreciate you as a person bro. Thank you

[@synchronicity458]

It’s sad that some of the most competent teachers aren’t technically qualified to teach a college course. Meanwhile there’s no shortage of professional activists PhDs spreading their ideology across young minds

[@Live2ride2live54321]

I have my degree in electrical engineering with a focus in utility technologies, and I’ve been a journeyman lineman for 15 minutes. I am always thoroughly impressed with your level of understanding and what is a relatively complex focus. It’s rare I see a KZbin video that talks about electrical without me finding errors in the theory as it’s explain, however, your work is very impressive! I suppose the only bone I’d have to pick is the lack of specifications regarding Delta and wye circuits in relation to grounds or short conditions. However, the diagrams clearly showed Delta or wye configurations 🤷🏻‍♂️ so all good!!

[@FowlerAskew]

As an EE who much prefers embedded systems and low voltage stuff, the idea of grounding into the actual earth has always seemed very odd, so I appreciate you making a video all about how it works and where it's used. Your videos are much more engaging than the power distribution class I had to take, maybe if I had you as a professor I'd be more interested in the field. I would definitely be interested in seeing a video on HVDC transmission systems, I run across a lot of people with misconceptions about why we primarily use AC for distribution instead of DC, and I'm not really up to date on the state of HVDC projects, so it would be cool to see your take on how the technology is progressing and what benefits it gives us.

[@pisspee2099]

re: why we primarily use AC for distribution? It comes down to MONEY. If we had DC power lines, we would need more copper.

[@FowlerAskew]

@@pisspee2099 I don't think the primary factor is more material in the lines, but the expensive electronics required to increase or decrease the voltage in a DC system. Compared to a transformer they're much more complex. My understanding is that because DC transmission is significantly more efficient, it can make sense when you have few conversions, like long distance connections between grids, or when supplying power to customers that can use DC directly, but for things like household distribution the cost of the equipment and the cost to retrofit everything exceeds the savings from improved efficiency

[@AtlantisArch]

There are only a couple of HVDC lines out there, mostly in China because they have a *huge* distance between population and production sites. DC outperforms AC only on very very long distances. The main issue with DC line is safety equipments.

[@danielnoriega6655]

@@AtlantisArch no, the main issue with DC is the fact that you "cannot" (except until recently) transform it to higher/lower voltage, thus you would basically transmit at the voltage that is going to be used, thus much more current will flow through the power lines, causing huge losses and the conductors need to be huge as well.

[@lonlockwood9481]

This is the first time I’ve ever left a comment. I’ve been watching practical engineering for a few years and I’ve always enjoyed and appreciated your videos. I am an electrician and you did a really good job explaining where grouted electricity goes . I would like to see more videos on electricity !!!

[@yeahmon215]

Good ol grouted electricity

[@simonruszczak5563]

@@yeahmon215 Hey, it's his first comment.

[@turboturd7954]

​@@simonruszczak5563nobody does a first comment without a spell check, nobody...

[@artnull13]

Even his lathe and wooden bowl videos?

[@earlestes8649]

@@yeahmon215nobody is perfect, including you 😂. lol

[@pulsecodemodulated]

Those single wire earth return systems are quite commonplace here in Australia. I remember being fascinated by them as a kid and asking my dad, who is a physicist, how they worked. I recently purchased a pair of local battery magneto crank telephones, which I have setup as a novelty intercom system. I was recently reading about how some remote telephone lines used a earth return system, so at some point, I plan on doing a little experiment with the phones to see if I can get an earth return system to work between them.

[@gus473]

You may be interested in the open-wire telephone system from the rim to the bottom of the Grand Canyon in Arizona! It's on the historic register.

[@twocvbloke]

Ground-return is how a lot of magneto-based phone systems worked, cheaper to use one wire per phone, and, if you have long wire fences on reasonably insulated posts, you could even use your fenceline as the main wire, just by clipping onto it and connecting the other terminal to the ground... :)

[@darylcheshire1618]

I have a photo I took of a public phone box at Yaraka QLD, when booking a hotel room, I rang this long phone number and asked for “Yaraka 4” and spoke to a manual exchange. This phone box had an A and B button and a crank handle. People I showed this photo to said they wouldn’t know how to make a phone call. This was in 1987. As a kid in the 1960s I had an uncle who was an electrician who had a whole bunch of hand crank generators as he was involved in upgrading the telephone system.

[@pulsecodemodulated]

@@darylcheshire1618 Fascinating! I had always thought that the last manual magneto exchange in Australia was near Geraldton WA and closed in late 1985. The two PMG 403MT handsets I have were made by British Ericsson in 1957 and 1960 respectively, but both have Telecom Workshop Hobart test tags on them from 1979 and 1982, meaning they were probably last in service on remote exchanges in Tasmania until sometime in the mid 1980's.

[@darylcheshire1618]

@@pulsecodemodulated Yes there were a few in Queensland, also in Yaraka the freight train service still carried passengers until 2004 in a passenger compartment in the guards van. This was a car-goods which is different to a mixed which was a passenger car attached to a freight train. This was the reason I travelled to Yaraka 3-4 times from 1987-1999. There was a rail fan called Richard who drove around and took photos of all the remaining manual exchanges and spoke to the old ladies that ran them, he would exhibit these photos on rail enthusiast slide nights. Mostly delapidated tiny buildings in rural areas.

[@ArchIVEDCinema]

I'm an engineer on the civil/structural side of a company that designs transmission lines and substations, and I always love when I can learn and understand more about what the electrical engineers on the other side of the building do! Thanks for this!

[@jogandsp]

I'm not gonna lie, when I first saw the video title I thought "this is a question that does NOT require a 20 min answer." But now that I'm watching it, this video is so fascinating and I'm learning a ton. Thanks for making it!

[@Sw3d15h_F1s4]

I'm a senior undergrad in EE, this video is great! You did a great job explaining the many many different meanings of ground without waving your hands about semi-true analogies, and you did it in an easy to understand manner. As a kid I used to be confused about neutral vs ground in typical house wiring, after all they are bonded at the panel so shouldn't they be the same? No, of course not! Current flows in a closed loop, ground vs neutral vs return path or whatever you call it is just whatever loop that current happens to be flowing back through. Now just wait till yall get to class and learn that all the electrons move backwards...

[@andrewbalzer6263]

Or wait until you start learning about it from the physics side and find out the electrons aren't flowing at all in either direction! There are so many abstractions we apply to complex systems to make practical assumptions that can actually be applied.

[@harmsc12]

Back in 1997, a nasty October storm knocked down some power lines near my home. One of our dogs ended up getting her back legs paralyzed after going outside and had to be put down. We thought she stepped on a downed line, but after seeing your demonstration with the Hulk Hogan figure, I think I have a better understanding of what happened. Just going near the downed line would have been enough to do the damage.

[@tungsten2009]

There are back leg wheel chairs....

[@samsunguser3148]

​@@tungsten2009we don't know if that was the only issue with the dog after the incident

[@tungsten2009]

@@samsunguser3148 That's fair

[@FreejackVesa]

@@tungsten2009oh brother. I'm sure they loved their pet and did what they could. Sure, in 1987 maybe they could have gone to a machine shop to get a custom wheelchair built for their dog, but I dont fault them if they didn't.

[@tungsten2009]

@@FreejackVesa Well, in any case, RIP little doggy, fly high.

[@randallkelley3600]

I'm aware of a number of cases where cast iron water mains developed leaks due to electrical grounds from a business like a welding shop. The grounds weren't on the main itself, but there was enough current to slowly strip iron from the pipe eventually causing leaks.

[@Flying.Dutchm4n]

As a high voltage engineer I know how difficult it is to explain how earth works, but this is an amazing explanation. Great job Grady! (Can you make a Dutch version for new colleages? 🤭)

[@marcobotha9376]

I having teaching myself designing circuits and ground is a difficult concept to understand as there is more than just one type of ground and how should different types of ground be connected to prevent ground loops and EMI noise

[@latticepoint5245]

You can try auto translating the captions to Dutch

Agree this is an excellent video introducing the topic

[@WackoMcGoose]

@@latticepoint5245 This. I have auto-translate set to Polish for fun, and it's certainly _interesting_ to see what videos seem like po polsku...

[@skyfeelan]

aren't you Dutch very good at english tho?

[@TheMrPits]

I actually caught myself asking myself this question during a road trip this past week. I found myself sleeping on the floor of a one room (10x12) cabin, on top of a ridge at 6,000 ft in elevation, while a big storm moved in. At the sound of approaching thunder, I began to consider how the cabin was grounded... or if it was. I hadn't been ready for rain, so ended up sleeping on the floor at the base of the loft, an aluminum ladder pretty much right at my back heading up to the loft, under a gabled metal roof. Now I have been in a fire lookout tower during a storm, and knew how the grounding worked on those with metal wires that ran over the roof, down the sides of the tower, and into the ground below. But, this wasn't a tower up in the air, and I was rather close to that ground. Now I knew the guy who built the cabin, he is a bridge engineer, so, figured, this was grounded sure thing. But.... I have not seen any metal wires running down the outside of the cabin walls, or along the roof. Maybe there were grounding rods in the walls Suddenly not sure, decided sitting against the bottom of an aluminum ladder, on the cabin floor, maybe wasn't the best spot with lighting coming. Got home and found this video and now have come to the conclusion.... yeah, wasn't the best spot. Turned out the cabin was not grounded.

[@RWBHere]

If it wasn't grounded then it would be somewhat less likely to be struck by lightning than a grounded cabin would. Swings and roundabouts.

[@Calico5string1962]

Hi Grady, I always enjoy your videos. Thanks so much for taking the time to create & produce them! As an industrial/commercial electrician for nearly 40 years (recently retired but still "working"), I found this video particularly interesting. As a note: Nearly all modern transmission & distribution systems (with exception of rural SWER systems) always keep a grounded/neutral conductor present with the phase conductor(s), and that ground/neutral conductor is bonded to the earth at every line pole, and every transformer/switch/breaker/recloser location, thus enhancing the earth-ground "connection" on the neutral conductor sytem, which keeps the potential difference of the neutral & ground minimized, in the event of a physical failure of a transmission/distribution line (like a downed pole). I.e., lots of connections to the actual "ground" to minimize resistance and differential potential. Anyway, great video! I always learn something new! Keep 'em coming! All the best from west Texas! ~Alan

[@moonasha]

also worth mentioning that there are ungrounded circuits that use isolating transformers, I want to say in hospitals or certain classified areas where arcs are a concern, definitely for pool lighting i think. And also that while these ungrounded circuits are indeed safer, if a neutral somehow becomes grounded, then a human could be unexpectedly energized, which was a concern in the early days of electricity, when most if not all circuits were ungrounded. The topic of grounding is very interesting, it blew my mind when I first learned the neutral and ground were bonded in the panel. I was going to school to be an industrial electrician but then covid hit... sadly never learned what I wanted to because the school shut down (programming PLCs and HMIs and that sort of thing)

[@usaturnuranus]

That line: "you may have heard that electricity takes the path of least resistance" followed by pointing out that in fact, it follows ALL available paths at various levels determined by their individual conductivity. Yes! That jolted(lol) my brain a bit, and makes a lot more sense to me now. Well of course it does - we all know that we can design a circuit that splits into X number of parallel paths, each having a different resistance, and the electric potential will flow through all of those paths simultaneously at levels that are based on the individual resistance of each path. Excellent descriptions in this video. Much goodness.

[@samstech963]

Great video! One extra thing, related to the example at 7:09: in some countries, such as Italy, France and Japan, the neutral and ground/earth are kept entirely separate in the home, and never connected together. In that case, during a fault (like in the toaster example) the current will in fact flow through the physical ground, and thus will be fairly low - too low to trip a breaker immediately. Because of this, an RCD/GFCI is required to make sure that power gets cut immediately after a fault. This is called the TT system, and is nowadays considered to be fairly safe and reliable, provided that an RCD is actually used (which is the case in the countries that make use of it).

[@RaunienTheFirst]

I was wondering, "what does he mean by a return path?" because the ground connectors absolutely do not reconnect to the grid at any point here in the UK. If your device has a ground fault, the current will simply... Go into the ground. At which point your RCD will detect that the return current is lower than the supply current and open the circuit. The American electricity system is strange. Not to mention their outlets and plugs.

[@samstech963]

@@RaunienTheFirst Generally speaking, the UK does in fact use a TN earthing system - generally a TN-C-S one, the same one used in the US, so the same principles apply (especially since houses in the UK aren't required to have earth rods). The exception is in rural areas, where TT supplies like I described are in fact common - but generally speaking, the TN-C-S system is the predominant one. The main difference with the US, really, is that the split (from combined neutral and earth into separate neutral and earth conductors) is done by the supplier, while in the US this is done at the breaker panel.

[@RaunienTheFirst]

@@samstech963 huh

[@traildude7538]

@@samstech963The old breaker panel in my basement connected the ground wires together and connected them to a copper rod that ran through the seam between the main basement concrete slab and the slab for the exterior stairway. When the wiring got updated at some point the copper rod got pulled, which took a serious amount of pulling power because, as it turned out, the rod was over seven feet long. I thought that was amazing, but an electrician had one of those copper rods on the wall in his shop as a bit of history; it was twelve feet long! The explanation was that anywhere between six and fifteen feet down under much of this town there was a natural gravel layer that water flowed through that was an excellent conductor due to the fact that except for the town the entire valley area was dairyland, which meant that the water flowing underground towards the bay was far from pure.

[@hvrbros8730]

studying to become an electrician here in australia, and we have the same system. we just call it "earth". but just like yours our ground/earth cables go straight into a copper rod submerged a metre into the ground, with an RCD to detect leakage to earth. i was very surprised to hear that their connects to neutral. is it less safe?

[@dangib4354]

Love the content. I’ve been a industrial electrician for 8 years. I worked ungrounded and grounded systems and I love how you have demonstrated it. Good work and thanks for sharing that very cool knowledge with the world.

[@oldroscoe2590]

A few years back my old house was having problems such as the washer not able to spin dry sometimes, dim lights at times etc. The cable TV would also fuzz up and checking that connection to the house I discovered the cab;e connection outside was warm. I called the electric company. They found an intermittent bad neutral at the pole. They redid the connection and things went back to normal. The cable was acting as an interment ground/neutral.

[@buzzaard7036]

I work for a cable company and years ago when we would physically disconnect customers at the pole you were supposed to check with a probe for voltage, occasionally someone would be in a hurry and not check and when they would disconnect the cable lights in the house would go out and sometimes things exploded because the neutral to the home was no longer connected and the home had been using the cable drop as the return path.

[@RobertSzasz]

Intermediately losing your neutral means various things in your house would be getting anywhere between 0 and 240 volts depending on how loads are balanced

[@complexity5545]

Good Video. Most people don't know that soil is a conduit. Your electric company has a topology map of recorded capacitance. They have to plant electric poles accordingly. Constructions have to plant earth bars in the ground for your house (and building). I am an engineer, but my dad worked for the electric company. He taught me alot of behind the scenes electricity stuff. Living in the country, I've seen lightning bolts strike really close and get absorb by trees and the ground. My dad used to go around the yard checking capacitance just for fun. He'll cut down a tree if it grows too big and had too much voltage (just for fun).

[@ralphbell1786]

We should be billing the power company for using the earth beneath our houses as a conduit.😂

[@mvmlego1212]

I found the diagrams a bit confusing, but I appreciated your combined use of them and other teaching methods (theoretical explanations, demos, practical examples, etc.) to make your point. This is a difficult subject, and I think that my chances of properly understanding electrical circuits is higher from watching this channel than it would be from any other source.

[@LoganLovell]

The top wires on a transmission line are called shield wires, often a smaller steel cable or now days a Fiber Optics cable ("OPGW") which can be used for telecom purposes. These are used to protect the conductors in the event of a lightning strike as they are grounded to the structure and consequently the actual ground. If the structure is steel, it itself is the ground "path" which is then usually tied to some sort of grounding rod or cable buried next to the foundation of the structure. If it is a wooden pole, then usually there is a ground wire that runs the length of the pole into the ground near the base of the pole. One of the lesser known issues with this is that people will attempt to steal the grounding wires off of structures because they think they can get money for the copper scrap. What they don't know is that it's actually just aluminum or steel coated with a thin layer of copper, so it's hardly worth anything in scrap.

[@jeffloveless6536]

You answered a question I had for along time and never asked. I kinda had figured the wire going down the wooden pole was ground but didn't know why. Thanks

[@Tupsuu]

We use 25mm2 copper in our city for the 20kv poles. and well all the other stuff too. No idea about the 110kv and 400kv lines tho

[@redraiderrider3289]

You don't know. Sit down please.

[@Matthew-ju3nk]

Once again you and your team have produced a very informative and easy to understand video. I have been in the heavy construction industry for almost 20 years and you STILL manage to teach me a thing or two in almost every video you make. You ROCK Grady!

[@WhereDoesItAllEnd]

love you pfp matthew

[@brianpait]

Man I love your calm, clear, and inviting speaking tone. It’s easy to listen to & because of that (and the highly technical based videos) you have a new follow!

[@jimhall583]

As an engineering student I was lucky to get a job working on the construction of a small power plant for a big manufacture in Buffalo NY. the construction of the switching yard for the plant was fascinating to me and involved a lot of copper rope and rods, plus three or four feet of crushed rock. It always seems kind of crazy to me that after months of construction and connecting a million dollars of equipment that it all comes down to one person covered in protective gear throwing a three-foot lever to make the connection.

[@goodmaro]

I asked my cousin (a railroader) what the metal straps I saw between sections of platform at a passenger station on the electric train line were for. He said it was for grounding, and that you could sometimes measure quite a voltage between structural elements and neutral on the line. Presumably these were generated by induction. Eventually I found the similar straps from these structures to earth grounds. If any sections became electrically isolated, they could present quite the hazard -- for instance for someone walking from one section to another. The straps kept all the sections at the same potential.

[@ke6gwf]

This is basic equipotential bonding. Everything in a substation or similar high voltage installation, even the fences and gates, are bonded like this, and they have steel grid mats beneath the gravel so that the ground itself is all the same voltage as the metal structures.

[@kozel0147]

This is one of your best videos, if not the best one. Grounding is insanely complicated and you helped me to understand it a bit more. Thanks! :-)

[@Dudeitzmimi]

I always liked how it's explained in circuits 1. Ground is just whatever you want to be your reference as 0v. So theoretically you could make the live wire the ground and ground would be -120v.

[@monkeyvittles]

Wow! Excellent job describing everything here. I’ve been doing ground grid design in substations for about 4 years now and honestly couldn’t have described it any more intuitively myself. So cool to see my line of work actually get a mention!

[@tsarodavid9730]

Nice pine of work

[@hootinouts]

Grady, I love your videos. I'm 64 and am always pleased when I can learn something new each day. I wish all teachers were as amazing as you. Although I have enjoyed a long illustrious career as a designer in the engineering field, education was an incredible challenge for me.

[@blacktimhoward4322]

This dude worked SO hard to make this basic and accessible and my dumb self still missed all of it 😂 I'm glad you make these videos sir, and I hope better minds than mine can get something from it

[@kayakMike1000]

What did you not understand?

[@blacktimhoward4322]

@@kayakMike1000 Man, I don't even know the difference between current and voltage. I only clicked because I watch a lot of videos from the Chemical Safety Board and WorkSafeBC. The WSBC vids talk about what to do if you're digging and strike a wire, so I thought maybe I would get this topic. Nope. Multivariable calculus? No problem. Basic electricity? I'm hopeless

[@BallstinkBaron]

​@@blacktimhoward4322voltage: difference in potential (think pressure) Current: flow of electricity (think how much water goes thru a pipe in a given amount of time)

[@skaetur1]

Yeah, when the Dominos logo started spinning, I lost it. I am NOT an engineer. ✍️

[@eklhaft4531]

@@blacktimhoward4322 If you are really good in multivariable calculus then you should be able to derive everything from the Maxwell's equations 😉. 😁JK

[@patrickbullock2136]

An effective approach toward understanding one of the most misunderstood concepts of electrical distribution. I particularly appreciated that you demystified grounding as simply adding another connection to the neutral to complete the circuit.

[@seanvinsick]

Professor in college: Today we're going to talk about electrical grounding. Me: ugh boring. KZbinr: Today we're going to talk about electrical grounding. Me: fascinating!

[@daze023]

Here, you are not distracted by uninterested incurious twits who can't sit quiet long enough to become engaged in a fascinating subject

[@poormiserablesinner4600]

Last year I was driving down the road during a storm. There was a tree that had blown over and leaning on some power lines. The part of the tree that was in contact with the power lines was smoldering, and I saw flames too. The fire department was on scene, but the guys were still sitting in their trucks. Pretty neat to see.

[@kenbrown2808]

yeah, nothing the fire crew can do except tell people to keep clear until power gets there to shut down the line.

[@MR-nl8xr]

LOL, yea they were "F that", we'll wait until it's off.

[@namibjDerEchte]

@@kenbrown2808 Actually some german fire crews now have spray nozzles that allow them to treat fires near train lines without having to wait for the power to get shut off and someone to come out and manually ground the line. The key is ensuring droplets instead of stream and enough distance to prevent arcing.

[@kenbrown2808]

@@namibjDerEchte train lines run a little bit lower voltage than our overhead power lines.

[@aschoenecke]

These videos are all so precious and valueable as introductory learning materials. Your quality is always top notch, better than the Discovery shows and such I grew up watching. You've already created a wonderful large collection on this channel, and I'm so happy with each new one you make. Thank you for all your great work!

[@ClayLud]

amazing video!! I've been an electrician for years and have never really understood grounding...even though I aced the tests in school. Whenever I'd ask a boss, I'd get a different answer and just knew they didn't have a full understanding either. Thank you.

[@notamouse5630]

As a practicing electrical and embedded software engineer, this covers the civil engineering side of grounding as a top level overview. There is also the Circuit board aspects of ground planes, shielding of sensitive signals, and having separate analog and digital grounds to avoid digital transition induced spikes interfering with rapidly sampled analog signals. For ultra-precise small current measurements in test gear, we can even create a ground-like shielding follower to minimize the current through the board surrounding the signal under test. That is isolation from everything by making your own ground-like signal. Also Star Grounding and avoiding ground loops and resonant ground structures. In circuitry capable of making GHz noise from transitions or signal frequencies near such, 90 degree angles can be bad, 180 degrees with a via can resonate at quarter wavelength. etc. Cell phone touch screens can get conducted EMI from insufficiently filtered power supplies. In short, ground is no joke, filtering of power and ground is no joke, conducted EMI is no joke. In electrical engineering, I tell people that board and wiring design mistakes have time to market and customer consequences, be cautious, check for bad things, have good review relationships with your fellow engineers. You will learn from their past mistakes.

[@JacobRiddle-tn9fo]

I would like email and have a correspondence with you. I am an electrician and currently working on public inputs for changes to the 2026 National Electrical Code.

[@notamouse5630]

@@JacobRiddle-tn9fo I am flattered, however I am also not necessarily the man for that job. I will however give some contributions here, take them as you may. In no particular order. 1) Disclaimer I have always been insured by employers, not a PE, never tested as such. 2) I mostly do embedded software, including safety critical stuff. Its really all about ensuring that code is sane, reviewed, cannot enter a state which cannot be left from, achieves full code coverage per certain guidelines, meets all requirements, and system integrates. Also cybersecurity and OS Dev and other higher level things. Volunteering to fix things that are not to par on safety is a thing for me, as is volunteering for hard jobs for experience. This is also generally not the kind of thing one adds stuff to NEC from. It has its own rules and guidelines. Often different per organization. That said: I have heard of some power engineering firms trying to make circuits that are essentially fly-by-wire (FBW) for safety of current conduction on in-place wiring. Class 4 circuits IIRC. Thats like a cross between what I do and what NEC may have in the future. I know because of a job interview I had. My advice is that the usage of FBW-like engineering controls can be an improvement because it would act like a fault mitigating circuit breaker in real time. I would not permit its usage to render unsafe wiring safe due to radiated heat hazards over long periods of time, but instead to permit its usage upon prior inspected wiring and I leave the definition of that to those who can spend the time. I also believe that a standard set of detections and mitigations should be developed to standardize testing of such products to prevent ineffective devices entering the market. 3) I am at best now a senior engineer with 5y of experience and I haven't been in a role close to power engineering in 4y. Not typical for someone contributing to NEC, I suppose. 4) I mostly talked in my prior comment about signal integrity for small low power circuits. More pertinent to PCB and consumer product design. 5) My best advice on what to add to the NEC is to find a way of enforcing sanity in consumer products by making sure that relays used in mains rated cooking appliances such as microwaves and toasters cannot ever fail shut. I just had this happen and that freaked me out more than any lab incident that ever happened to me. Scary fire and carbon monoxide hazard, always watch food or set spare timers, even with a microwave I guess. TImed contactor might be a good hack if you don't need the time on the microwave. I had headphones on and was watching KZbin when I wondered why the food smelled so good. My food had cooked for 5m instead of 2m. Timer was done, light was out. I deduced the problem before even taking it apart and got it right first measurement. I then rendered the microwave safe and extracted parts I wanted before tossing it out. Maybe I should have investigated further as to cause inside the relay, but so far as I can think of, it had a contact adhesion or something and was a 100 ohm contact. Arcing and sparking probably made the relay actually turn on without blowing up. Is there anything else you would like to ask, given the above?

[@markjames8664]

I’m an amateur radio operator. Grounding for RF needs special attention because most of the current flows near the surface of a wire. So a wide strip of copper is often used to connect to ground because it has a much higher surface area. You are supposed to have an RF ground separate from the power ground but that also needs to be bonded to the house ground. Metal towers also need lighting protection grounding. One odd thing: in the traditional AM radio tower the ground is part of the antenna-wires or metal grids called radials run far out from the tower for this purpose. More conductive ground is better for this and sea water is excellent. I’m no expert but people spend a lot of time on improving grounding and bonding.

[@michaelmoorrees3585]

As an EE, I have performed these experiments at home, though decades ago. The ground symbol used in electrical circuits, as the circuit "common", is historical. In the old days, the terms "radio" and "electronics" were used interchangeably. Radio, even battery powered radio, worked better when actually grounded. Simple way of understanding electricity. Note the term "circuit". It means a loop. For electricity to flow, a loop, or circuit, must be completed. Great video, explaining the use of the "ground", on the electrical grid !

[@sethproaps8899]

I'm a ham in general nowadays when we ground our radios its for two types of ground, a safety ground for reducing shock hazards, or an RF ground for unbalanced antennas like a monopole. However ground is not needed for balanced antennas like the dipole. There is also for lightning protection but its usually not part of the RF circuit

[@toddmarshall7573]

I'm amazed we don't even speak consistently about the direction current is flowing.

[@onradioactivewaves]

​​@@toddmarshall7573unless specifically required for the situation, current flows the same direction as power. Even though AC current flows in both directions in a single cycle in a DC sense, in an AC sense the AC current only flows the same direction as the power is delivered. I hope that makes it easier to understand. If it doesn't matter, we don't worry about it.

[@XEinstein]

Well technically for anything to flow you need a differential. Water won't flow unless there is a potential in gravity. Ie connect a horizontal pipe to a water surface and nothing will flow because there is not potential across the pipe. Angle the pipe downwards and a potential is created causing water to flow. Same goes with a wire connected to a battery or power outlet. Connect the wire to the plus and there will be no potential across the wire so no electrons will flow. Connect the other end of the wire to the minus (please don't actually do this) and because of the potential between plus and minus electrons now can flow.

[@MrAranton]

@@onradioactivewaves Thinking of electricity as a flow of current models reality but it doesn‘t reflect reality that well. In electronics we say current flows from + to - or live to neutral when we talk AC while electrons actually move from - to + in DC and just oscillate in AC. But the model works well enough so we keep using it.

[@Beryllahawk]

Really appreciated a new Practical Engineering today! Long day at the hospital (hubby had a heart procedure, he's doing fine!), and I was thinking about the electrical grid already, because while I was waiting (and bored) I got out Grady's book and started looking at all the utility poles I could see from the window. It passed the time nicely and now, I get to enjoy this too!!

[@HumanBeanbag]

My parents take my electronic devices when I'm grounded.

[@ronyhassan4407]

man that's brutal 😂😂😂😂

[@tomchidwick]

Grady, there are about 5 or so YT channels that I'll drop everything and watch the video, once dropped and notified. Yours is always at the top of that list! Thanks to you and your crew for making such excellent content. I found this one very fascinating and informative.

[@josiaharteaga3270]

Excellent video! I’m an electrical P.E. in California, and I deal with the world of grounding quite often. You explained it very well!! Cheers!

[@JonathanFraser-i7h]

In your generator thought experiment, there could be a current of about 2 microamps due to capacitive coupling. Of course if you drove the hot line into the ground, then you would get a pretty bad shock if you touched the generator, stopping which is ultimately why we have earth bonding.

[@evanc1721]

If there is no flow of current, what would happen with the energy (if any) produced by the generator? would the generator spin super fast?

[@JonathanFraser-i7h]

@@evanc1721 The generator itself wouldn't be producing much if any power. With no current flowing there would be no torque on the shaft and it would spin relatively freely. With no load the engine would likely rev up, but most generators have rpm governors that would reduce the flow of fuel to keep the motor spinning at the same rate. There would be some energy produced in the form of waste heat from combustion and some going to frictional losses in the both the engine and generator portion but there wouldn't really be any power produced.

[@evanc1721]

@user-oj9iz4vb4q Thanks a lot, this is very helpful

[@MrGlenferd]

I worked in grounding and this video brought back much of what i learned at the time. We had an area that gets ice storms and the weight of the ice on the high temtion line and the return would cause the poles to break so we removed the reyurn and improved all the grounds in the areacfor earth returns. I remember working on a hill of shale and having to drive 100 feet of ground rod to reach the water table and get adequate grounding. Another time i could not get it and we realized that we were in a valley completely surrounded by rock and thus insulated from the world. We run half a million volt dc lines from up north with earth returns and they can tell in the US what we are doing. I remember being told how material from the ground rods slowly dissolves at one and builds up on the rods at the other. We reverse polarity every so often to reversevthis effect. I hope I've got this right as it was over 40 years ago when i learned this.

[@AllYourFriendsThink]

Wow! Just wow! The demonstrations, the diagrams, the thoroughness, the narration - world class! Thank you for video; wish I'd had this in EE classes.

[@jessiebullock]

I’ve definitely noticed the increase in production value. You’re doing an amazing job. Keep up the good work!

[@tammyhollandaise]

A video or a short on grounding methods might be worth doing. It's possible to ground in sandy soil using an Ufer ground (rod embedded in a block of concrete) because of how much surface area it creates.

[@martindean3958]

This was the first video of yours I stumbled across and I’m glad I did. Amazing video with great detail. Keep up the great work.

[@sirsluginston]

Great video. As someone who works in an ESD safe environment with all of our machines grounded, I would've loved a brief demonstration on ESD PPE, and the role it plays in completing the circuit safely.

[@falxonPSN]

As an EE, it's cool to see some more electricity oriented videos. Your explanations were as clear as usual, and hopefully no Hulk Hogans were electrocuted during the filming of this video.

[@robertszempruch6540]

In an era where the human attention span has shrunk to mere seconds in a lot of cases, I applaud your ability to keep my attention and produce videos I am eager to watch!

[@TheFenrirulfr]

I am an electrician and with this video i finally learned / got an example of what we would call (translated to english from norwegian) Functional earth. The light poles with a singular wire, where the grounding of each light bulb is the literal earth acts as a neutral.

[@jacobdykstra8499]

As a Professional Engineer working in operations at a major utility, your recent videos about the grid and electrical engineering concepts have been astonishingly detailed and incredibly accurate. I am amazed how easily you are explaining rather complicated topics. Sure there are a few other details that could be added in but... It's a very complicated field and you perfectly nail all the important high level details. Almost all videos I have ever seen trying to explain electrical concepts like this are either a long university lecture or some other science KZbin channel or something who gets the details wrong. Not the case here, the video is quick and to the point while clearly demonstrating concepts even engineers often find tricky. You clearly do your research and have a solid fundamental understanding before producing your videos. Excellent work!

[@kennethross786]

One more thing. Some (maybe most) modern relays have oscilloscopes built into them, so they can detect not just the intensity, but also the waveform of the current. This allows enhanced protection, because some low-level faults may not get enough current to trip out the relay, but if the oscilloscope detects a waveform indicative of a fault it can still trip the station or distribution circuit.

[@rondickinson1907]

If there is no waveform acreen then it is not a scope. It is a microprocessor controlled relay.

[@erikpoephoofd]

I guess it uses a current transformer in series with an ADC to sample the waveform of the current. Then, some DSP is applied to detect problems

[@DaveEtchells]

Another superbly-done presentation, thanks! I hadn’t been aware that ground-return was a backup conduction method for HVDC transmission lines, it was fascinating to learn about the massive grounding array in the northwest and the ocean-based ground at the southern end.

[@daze023]

You (and we) are fortunate that yours are pleasant vocal tones and concise delivery I'm happy to try to learn what you try to teach

[@duncanw9901]

In undergrad, I learned about space weather and solar storms indirectly (space medical physics). One of the interesting consequences of space weather events (larger than normal amounts of charged particles hitting Earth) is that _huge_ potential differences can build up between the grounds at different locations. Pipeline operators have to worry about this, because the outside of their pipelines are basically giant wires embedded in the relatively nonconductive soil. If too much current flows, it can heat the gas inside, and cause all sorts of terrible problems. A similar thing can happen when the earth's magnetic field changes too fast, inducing currents in the pipeline. NOAA offers forcasts of this stuff for that reason. I'm glad I wasn't in charge of installing the first pipelines; I never would have thought about that in a million years!

[@3v068]

Grady, my goodness I love this channel. You have taught me so much about engineering that I would have never even thought about, even if I did get an education in a particular field. Your videos are awesome, entertaining, and very informative. Thanks for putting so much work and effort into your content!

[@kenhansew7892]

Thank you for another outstanding learning experience, sir. And it's not just your depth of knowledge and easy to understand explanations, but also a wholesomeness that is just bubbly refreshing! I am sure that this old-school guy isn't the only one that feels it. May God continue to bless you and your family.

[@mkhanman12345]

i like to learn

[@philkarn1761]

Speaking as an electrical engineer, I have to say that for a civil engineer you do explain electrical concepts quite well. Bravo.

[@randydueck6870]

Your videos have always been a favorite as I drive to my civil engineering job in the morning. I also got slightly obsessed with electrical grids during the February 2021 winter storm in Texas where we lost power for 3 days in Arlington. Thanks for proving that civil engineers can understand electrical engineering😂.

[@hazardsharp3125]

As an electrician, this video is very important. I really like how you showed that voltage is a relative value between 2 points. A lot of people I work with make the wrong assumptions about grounding and how it plays many rolls in electrical systems, including being a local 0 reference voltage point.

[@abpsd73]

I remember during my electrical apprenticeship that so many guys couldn't understand grounding at a service box, where you're making the ground potential the same voltage as the ground potential as the grounded neutral at the supply transformer. Then try to explain to them why neutral/identified and ground are two different things and why they can't be interchanged or interconnected at multiple points in one building.🤣

[@HotPotatos]

Nice video! Answering questions I would never think of but are so interesting

[@msromike123]

That's the best instructor! Telling you something that is interesting, but you didn't have enough base knowledge to even ask.

[@smmmokin]

Anyone who had the option to make a 15 second video but knows enough to make it 20 minutes is the kind of person that deserves respect. Props, bud.

[@justalonesoul5825]

I really love your models, they're so incredibly educative, and yes the overall quality lately has been ridiculously good, there's such variety in the content proposed, you guys do wonders! It's funny to notice that when it's not about electricity, it's often water, or traffic... all having in common the dire need that all things keep flowing properly! Thank Engineers for all that infrastructure!

[@bruce-le-smith]

Thank you!! This always bugged me, but all the electricians just say 'it goes in the ground, that's the answer, stop asking questions'. Glad to know that there is more scientific theory and methodology behind the concept :) Keep the great videos coming Grady!

[@trout3685]

Explain what you learned.

[@IIISentorIII]

@@trout3685 is this a multiple choice answer?

[@t.r.4496]

We took a 34.5 kv three phase 1000 kva transformer to 12kv transformer, connected to 35 ground rods placed around and inside a pond energized it with a HV breaker and the settlement in the pond went straight to the bottom and the water turned crystal clear in a flash. Never in my life have I seen anything like that before and probably never will again. The electrical engineer created this monstrosity of a hookup. I was amazed.

[@buckodonnghaile4309]

What was the purpose of doing that? Sounds interesting

[@teeanahera8949]

I think you mean the sediment not settlement.

[@t.r.4496]

@@teeanahera8949 yeah autocorrect got me I didn't proof read it. I did mean sediment.

[@t.r.4496]

@@buckodonnghaile4309 I don't know why I didn't see this comment earlier. Anyway this was at a coal washing plant and the water was used for the plant. The pond had become full of sediment and they had cleaned the pond out. Instead of waiting on the water to clear up on its own which would take a week or longer this idea was thought up first. It was just so the sediment wouldn't get into the pumps and system lines and clog them up. The plant was down a half a day instead of a week or more. If they weren't producing clean coal they weren't happy as they were loading out three 100 car trains a week and the trains were scheduled so any delay the railroad would penalize them an enormous amount of money.

[@philhoward4466]

what voltage was it energized at? three phase i assume. glad you had that transformer laying around, spare. i wish i had one.

[@henryryan4096]

I’m getting a better understanding of earth ground thanks to your video, now I have to watch the video a few more times. Thanks Hank Ryan Electronic Technician 35 years

[@nferraro222]

Excellent vid. It's not just a safety issue. If people knew just how much hell, poorly grounded buildings and ungrounded shields, can play with electronics, computer networks and security systems, they'd pay more attention.

[@mikebarushok5361]

Shielding is a subject worthy of a separate video. And would have to touch on how power returns and shielding works in situations like cars and aircraft don't have any earth connection.

[@nferraro222]

@@mikebarushok5361 If the installers and tecs I used to talk to are any indication, it would probably be too boring a video for anyone to watch. I lost track of all the systems that had problems that were traced back to ground loops, unshielded cables and un-bonded building additions.

[@TheRealAverageZac]

as a telephone lineman, this is extremely interesting and helpful. Some day, I'd love to see a video on inductance and its causes; I recently encountered 240v AC inducted into a 350ft span of aerial copper telephone wire, and am still at a loss as for exactly how/why this is happening

[@rcpmac]

It was changing your iPhone as you stood there wondering. 😉

[@CharlieRAnimaMX]

EE here. 240V is a very rare (almost impossible) voltage to be induced. [At least in my image of what a phone line is, it is an ideally twisted or balanced pair that should be located below the height of the low voltage distribution circuits (AKA the lines that feed the houses) on a pole ]. more than induction The most probable thing is that there is some line knocked down or drifting on the telephone line. (or someone with bad service tried to inject current). If the line is very long, it may have been an accumulation of Static due to the friction of the wind, etc. And in that case, it could be that the combination of insulator and conductors acted like a giant capacitor.

[@TheRealAverageZac]

@@CharlieRAnimaMX Very interesting... it's worth noting that the 240v reading I got was via a non-contact voltage detector; I later read two conductors (white-blue and blue-white in this 6pr twisted-strand cable), and saw 37v AC between them. This is with both sides open, and only reading this 350ft span (approx 400ft total, 350'' between poles plus the vertical). I had not considered friction; that's fascinating, and something I will be studying more. I initially suspected solar activity, as I discovered the voltage (the hard way) during the peak of activity a few weeks ago; however, testing a nearby cable (of approximately the same length, but that ran perpendicular to the power instead of parallel) showed no voltage other than the 45v DC used to run POTS service. My dad (former construction electrician) suggested that it may be due to the setup of transformers; essentially, there is a transformer on one pole that feeds to another pole before reaching the service drop; along the same stretch are lines to a second transformer that then leads to a second service drop. I was told (and could be wrong) that the local utility uses two-phase power in the area, and having a service drop run parallel to main lines can cause issues; if you don't mind answering, is this true?

[@brandonrobertson6327]

I have been a telco maintenance tech for over 20yrs. I have seen 525Vac induction on a aerial self supporting 6pr. The drop was adjacent to a 14.4KVac feeder. What you typically see is adjacent metallic wires with AC induction, the communication wires acting as a secondary of a transformer. In a transformer, the primary and secondary coils do not touch. They are insulated and wrapped around the same iron core. The expanding and collapsing of the magnetic field is what induces voltage from the primary (source) to the secondary (field side). So on the wire used in communication and in your strand that hold the cable you are suspending up will be excited by the expanding and collapsing field. How much depends on proximity, humidity, and even the wind (friction of the dry air over the metallic wire or strand). I normally see this in where the protective ground shield is either not bonded correctly or has deteriorated to the point that it burns open. The shield burns open through contaminants that cause electrolysis and the shield breaks down as the flow of induced voltage pulls electrons away to the more noble adjacent metals involved in the system. Now back to your strand that hold the copper, coax, or fiber up. That strand should be bonded to the multi neutral at every point available on joint use poles. I know to save cost, if you are on your company's owned poles, there may not be a ground at every pole like the power poles tend to be. That is why your engineering dept should at certain intervals on the owned company pole line should periodically ground every for example 10 poles in a long run. This ensures that not only induction is bleed to ground, but unwanted faults like electrical lines that may come in contact several miles down the road or lightning strikes has a path to ground. Like the example of the 525Vac induction I found on the job. The first thing I did was to stop working and call the local electric dept. After it was determined by a clip on AMP meter and close visual inspection by the electrical lineman team and myself of no physical touching of their conductors to my service drop, the electrical lineman used insulated gloves to ground my drop strand to ground and watch the induce voltage go from 525V to 72V with only about several hundred milliamps of flow on the strand. This was interrupted as induction because even a real fault, the current would have been much higher. So, after determining it was safe (I could still feel the static field, so I still used insulated gloves) I proceeded to bond every point I could on this 2 mile run. The end result was that the overall voltage dropped to about 12Vac which by my company standards fell well below acceptable guidelines. Always use you high voltage detector and when in doubt, call the local power company. Hope this helped, stay safe out there. Safe creed..... "There is no job or service so urgent that we cannot perform our job safely."

[@phillyphakename1255]

It's like when a guitar string vibrates sympathetically with another. There is a wave of energy which propagates away from the source, guitar string no1, it hits a slightly movable object, and that energy wave imparts a force on the string no2. Same thing as with a loudspeaker at a concert and your ear drum, the speaker vibrates, it goes through air, it hits your ear drum, your ear drum vibrates at the same frequency, just a bit less than the speaker. Of course, this falls off with distance, it's quieter the further you get. Wires vibrate electromagnetically, they produce electric and magnetic fields going away from them. So you take a secondary wire, put it next to the first, and the eardrum will vibrate. Same frequency, just with a little bit less power. This is how transformers work, you want to reduce the losses, so you make the wires really really close together, like putting your ear drum near the speaker, and you want to increase the length within the same volume, so you coil it up really really tight, like getting a bigger eardrum. Transformers also have some weird properties with the whole step up and down voltages thing, but the intuitiveness of the analogy breaks down.

[@floorpizza8074]

Grady, a potential video idea... Dry pouring concrete has become quite a rage lately. There is an ongoing argument on the internet about whether or not dry poured concrete is as strong as wet pour. Since I know concrete is one of the things you've covered very well in the past, a video from you showing the strengths and weaknesses of both dry pour and wet pour would be great. Might help to answer a few of those wet vs dry questions floating around the 'net.

[@JamesIcom]

This is the reason why London's underground subway train network uses 4 rails (aka the 4 rail system). The track consists of 2 X running rails and 2 X power conductor rails. The outer conductor sits next to one of the running rails and is energised at a potential of +420 volts above ground. The central conductor rail sits down the middle of the track (in the middle of the 2 running rails) and is energised at -210 volts below ground. Thereby the potential difference is 630 volts DC. This was done primarily to prevent stray currents from leaking into the cast iron tunnel segment rings and causing problems with electrolysis to nearby water pipes and other underground service pipes / cables. Whereas on the national rail network (overground trains) the negative return is done just using the running rails. For more information on how this works, checkout Jago Hazzard's video called "Underground, why four rails"

[@56independent]

You should bring up the term "potential difference" for voltage; it makes things a lot simpler to visualise

[@blackkissi]

did you watch the video? 10:36

[@56independent]

@@blackkissi oh. I still feel like it could be better if they explained the term more fully in describing how voltage is a difference.

[@gregorschoepf4840]

The first experiment with the generator. I think the capacitance between the generator, its wiring and the ground (even if its very small there still would be a capacitamce) would result in a loading current if the generator outputs dc and in a continuous current if the generator outputs ac. Then the mental model would also need all the stray capacitances and inductances which can occur in every circuit. This is especially important in high voltage applications.

[@johnburgess2084]

Many years ago, before 9/11, our Portland-area amateur radio club was invited on an in-depth tour of the Celilo converter station by an employee who was also a member. That was the most fascinating tour I think I've ever been on, including some behind the scenes looks at things most folks never have a chance to see. (And probably never will again, since 9/11.) I truly await your explanation of this, or any other, DC Intertie station. 500 kV, plus and minus -- wow!

[@DanielinLaTuna]

I hope you had the chance to visit the location of the grounding grid. It plays an integral role in the operation of the HVDC intertie. Down here at the southern terminus of the Pacific DC Intertie (also called the PDCI, or Path 65) we run heavy conductors to the Pacific Ocean, at Malibu California, to the Malibu Electrodes. The Celilo Electrodes basically connect to the Pacific via the Columbia River. It’s an important component of the high voltage DC (you’re right, one million volts pole to pole, or 500kV per pole) because sometimes the DC converters may fail to single pole operation, in which case the ground return allows Los Angeles and BPA grid operators to shutdown the DC in an orderly manner. From what I remember, we can stay in ground return for twenty minutes (it has something to do with heat stressing the underground copper cables from Sylmar Converter Station to the Malibu Electrodes…

[@johnburgess2084]

@@DanielinLaTuna Nope, didn't get the chance to visit the ground electrode areas. But those high voltage rectifiers ("Flaming Valves") were impressive. And all in heavy-duty wire-enclosed cages. Perhaps I'm remembering incorrectly, but I believe the operator said that the resistance through the ground path is actually somewhat lower than through the main conductors. And then there's the switching to convert all that DC power back to AC. Nothing like those little 3.3V to 5V converters in computers! So much memory lost in so little time!