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@@stefannilsson2406 Ya I am surprised that ELCB/RCCBs are not standard fixtures in the home US electrical distribution panels. Who would have thought that making sure that the making sure that current leaving the live connection should equal the amount of current returning through the neutral for the whole house would be a much better idea than to only have it in the bathrooms
This is all the information I wanted to know. Why is it so hard for someone to answer this for me when I ask it. This video is short and to the point and I wish everyone would explain things this way. Thank you
The Internet acts like only electricians or people trying to mess with things around the house they maybe shouldn't are the only people trying to learn about electricity
#1 cause: by being alive, easilly avoided by using time travel to give your dad a condom/swift kick to the goolies. disclaimer: this is not legal advice. condoms are not 100% guaranteed to work; I hold no responsibility for accidental discovery of infidellity. time travel may cause motion sickness, fatigue, dorcelessness, etc. so consult -the- a doctor about it first.
How to avoid it? De-energize every circuit before you work on it, make sure you understand grounding (as explained in this video), make sure you ground all your circuits, make sure everything is safe and all people and animals are not touching the circuit before you re-energize it (lock out/tag out). Pretty basic concepts, I think.
This reminds me of a terrible incident here in Australia a few years ago where a young girl received a shock from the house's ground wire. The family had complained to their housing authority for a long time that the electrics in the house were faulty. The girl had gone outside to turn a hose off, barefoot, and received a shock from the ground wire. She survived, but can no longer talk or walk - I'm not sure how much she's recovered since. I always wondered how one could receive a shock from the ground wire, since I always thought *it* was the 'safety feature' - but I see with a large enough fault they can be carrying dangerous current.
Dumb family was waiting for ‘authorities’ to fix electrical problem in their home?!?? What happened to hiring an electrician? Well - pity their daughter had to pay the price for their empty heads and scroogyness….
That is, at least as far as I heard, exactly why in Serbia it is forbidden to use a TN system in houses. I think many old ones still are TN but a lot and even mine from 1976 has (tested) good earth rod so it is very easy to switch to TT.
I own a engineering business. I went to use my tig welder ( set on 180 amps ), after starting to weld the setting seemed very low on current. I stopped & checked that the machine was set correctly & started welding again. The current was still low but now there was a burning smell & smoke in the workshop. After a bit of investigation, I had left the earth lead for the tig welder on another steel bench , but I was welding on a jig that had a 3 phase drive motor. The earth circuit went through the frame of the jig , the 3 phase motor, out to the earth stake , back to the bench grinder on the other welding bench ,into the earth lead on the bench. The smell & smoke was the lead for the bench grinder, as this was the smallest wire in the circuit & couldn't handle 180 amps it melted .
@@robertsomerville5377 okay…so not an engineer but you own an engineering business. Please explain, b/c thats like a non-Doctor owning a Doctor’s Practice and playing around with the Patient’s files…
I held my breath through this, waiting for the big fatal mistakes, but I didn't find any! Good job lol There was one minor one and an oversight. The ground rod isn't only to dissipate static, it's what references the entire ground and neutral system to be Equal Potential with the dirt, and also the water pipes, building frame etc. You didn't mention how the ground rod is also bonded to the water pipes for this reason. And when you said that the fault current will travel back to Source via the ground wire INSTEAD OF through the earth, that's incorrect, it takes both/all available paths, so some current will flow through the earth all the way back to the power plant itself. It will be very small, and if you hook a wire to a ground rod and connect a hot wire to it, you won't trip a regular breaker so little current flows, but SOME current does flow. But still, you give a better explanation than most people ever have lol
Hm, i have a question then: If the neutral at the transformer is sticked into the earth (ground rod) and also at my house, and that has a very high impedance, how is then the current able to pass my body when i touch the Live wire? It should actually harder since in most cases i dont have a direct connection to dirt where it could flow back to the transformer or even my houses ground rod. What happens here then??
@@gandalf1783 if you are insulated and touch a hot wire, nothing happens. Just like a bird sitting on a power line. However, moisture is present in a lot of things, and most shoes are not completely insulating (sweat from the foot combined with pinholes in the sole etc), and so electricity can often find ways back to Source. For instance, if you are standing on bathroom floor after someone took a shower, the floor might have enough moisture on it to make a current path to a ground-bonded water pipe. You can also simply touch both terminals on an outlet. Or on carpet, if the humidity is high enough there might be some conductivity, or maybe you are kneeling on a nail beneath the carpet and the board has some moisture because the crawl space has high humidity, and the board is grounded to the damp concrete foundation. However, if you are wearing dry shock hazard shoes which have a dielectric barrier in them with no pinholes, or you are standing on a dry rubber anti shock mat, a clean and dry fiberglass ladder or plastic stool, then you can touch a hot lead with no shock, because there is no where for the current to go. All of the situations I mentioned before are very high impedance circuits, but it takes so little current to be dangerous to us that we can still get that shock. Now, I have gotten a lot of shocks in my life, between faulty equipment (not my fault) and working with electricity (my fault lol), and most of them were more straight forward, standing on wet surfaces, or touching both sides of a circuit, like the time my hand slipped on a large motor starter overload reset button and I punched across the 3 phase 480v terminals with my knuckles. I was actually standing on wet metal when it happened, but I had dry boots on so the only shock I got was between phases across my knuckles. I also was in the habit when I was working on open control panels like that to keep one hand behind my back, which may have saved my life that time, because if my other hand had been holding the cabinet door at the time it would have been much worse. I had an old electrician friend who used to never put cover plates on at his place so he could test the power easily if something went out, and he had to lick his fingers to be able to feel 110 v lol And usually he had to touch across both terminals or touch something grounded, because he would not be grounded standing on dry dirt or concrete. But it's hard to tell for us normal people whether what we are standing on is indeed dry enough to insulate us from ground.
this a 3 min video, you are more than welcome to create content, this is over simplified for the sake of education lmao he wasnt gonna take EVERY what if just for people like you that likes to complain about everything jesus
You are correct but it goes further! The "Ground Wire" connects different areas so they are at the same potential. This is most evident at the star point on a transformer. The star point is the source of the Neutral connection AND is bonded down to the body of earth, so if you touch a Neutral whilst standing on the floor there is no potential difference, no Voltage and therefore no current will flow! The services in your home and workplace also have an Earth point where the Gas and Water pipes are connected together (there may also be cross bonding at your hot water tank, boiler and sinks). This means that All "Earthed" points are at a similar potential. This may seem obvious but if you have adjoining properties that are fed from different substations there can be a potential between different lives (even on the same phase) and it is the earth connection down to the body of earth that keeps this to a minimum!
It could have been worded better though. He states that electricity "prefers" to travel thru a low resistance path (here a wire rather than the actual earth), but electricity will take ALL paths, the current will be higher in the lower resistance one. eg if you put a 1 ohm & a 1000 ohm in parallel across a power source, both will carry current. The 1000 ohm will only have 1/1000 of the current that the 1 ohm resistor does, but it's not zero.
@@edwardscomputers The way he said it inferred that it ONLY goes thru the low resistance path. It's a common statement "electricity goes thru the path of least resistance", which is true but it ALSO goes thru the high resistance path(s).
Correction: Current takes all paths. If it took only the least resistive path then parallel circuit wouldn't exist. Yes, less resistive paths cause currents of high magnitude and high resistive paths lower the current's magnitude. That's it.
Current takes the path with the least resistance always. But it doesnt mean it has to go in a single line. Its path can be devided and make it even less restrictive. Electricity is just moving electrons. So if they ALL go in the less restrictive path it becomes more restrictive than splitting 80/20
Here in The Netherlands, a ground-wire is green-yellow. Also, most houses only have a ground-wire connected in the ''wet-rooms'', bathroom, kitchen, garage(sometimes), but not in the living room, bedroom etc.
Here in america it's standard for all receptacles to have a ground wire and a third prong to provide equipment ground. Y'all most likely have full-house RCD/GFCI protection, which isn't standard here, though we're getting more and more GFCI/AFCI requirements as the years go by.
Nonsense. PE wire everywhere and earth rods were becoming standard in Yugoslavia by the 80s. You can't tell me Western Europe had worse safety standards than us.
I've had desktop computers before with crummy power supplies that would shock you when you touched the case. Grounding was the solution in these situations as it allowed this stray voltage a path back to panel neutral.
@@stevecarter8810 Panel's only used standard U.S. style circuit breakers. Not enough current flow to trip the breaker. Probably a current flow of 500ma or so.
And you kept those in your pc?? Brave man! (are you sure it wasn't just static buildup on you? Wool sweater, socks on laminate floor, that kind of thing... )
That is not a sign of a bad power supply that's a sign of a GOOD power supply. It means you have a noise filter and these filters leak a few mA to ground. In my grandparents house from the 60s that had no PE wire on most or all outlets I would get a zap from touching a computer case or even metal keyboard with even slightly wet fingers. It is because of this. Doesn't help it was all on one power strip so all other switch mode PSUs with filters were adding more current to the earth wire that went nowhere.
Electricity takes all paths, not just the "path of least resistance." It has no way of knowing ahead of time which is the lowest path of resistance. The percentage of total current in a conductor within a circuit is proportional to its resistance.
All of this guys videos are really great! All you have to do is look at some of the other videos on various subjects to know that Tom’s videos all excellent, uniform, and a super great resource for learning said material. Definitely one of my favorite content creators on electrical subjects!
Sir, with due respect, "path of least resistance" is incorrect. The reason for ground conductor having low resistance is for the ckt breaker to trip faster due to having higher current during fault condition. Everything that is in parallel with the circuit still has current flow but just in proportion with its resistance. Appreciate your very informative presentations, still. 👌
Correct, electricity doesn't take the path of least resistance, it takes ALL PATHS of resistance, even in a "dead short" since no matter what everything has some kind of resistance. He did however say "preference of path of least resistance" meaning technically majority flow but even so he should have clarified it
Excellent...my mind is relaxed after watching this video... before watching this, elecron fl ow , grounding etc is a black box for me... thanks for the efforts in making this video... please make more
Thank you very much! I felt like you made this video just for me. My washing machine gave me a bit of a shock when I touched the water and I wanted to ground it (pun intended). I only knew so little and this was the first video I opened, and to my surprise, you used washing machines as an example.
This way of how grounding works (from the grounded component earth wire through the neutral line back to AC transformer) ONLY applies to specific TN-earthing systems (TN-C and TN-CS). It does actually not apply to TN-S and TT earthing systems, used in Europe and Asia (and US at gas stations ect. by exception). In a TT-earthing system (common in Europe) the return fault current actually IS returned by going trough your premise ground rod trough the earth to the distribution AC-transformer ground rod connected to its starpoint or neutral wire. There is here NO link between the neutral line from the supply at your premise to the grounding/earthing wires in your installation. Because of the higher resistance of the earth soil the current will in a lot of cases not be high enough to trip your normal circuit breaker (overcurrent protection) while still being deadly dangerous. Therefore a RCD/GFCI-device covering your entire installation at the supply is mandatory in most countries, as it will trip much faster at a the existence of a ground fault current of 300mA/30mA. When in a TN-C earthing system the neutral gets broken (by heavy weather at power poles for example) you get a dangerous situation because (1) the only return path is trough the soil with higher resistance and the installation does not always have a general RCD covering the entire installation and (2) with the lack of a neutral conductor the devices connected between the 2/3 phases and the in-house neutral are getting connected in serie leading to a dangerous abnormal high voltage on your 'grounded' equipment. Using a PEN-conductor (combined neutral and protective earth condictor) as in this video can be really dangerous if the PEN-conductor is broken upstream. In the UK/Australia this setup is called PME (Protective Multiple Earthing), but it basically the same as TN-C-S with additional ground rods along the way to reduce the electric potential created by the PEN-conductors themselves because of the long distances/resistance of the cheap conductor materials used. So based on your earthing system, the ground rod at your premise is besides lightning strike protection possible also used as a conductor back to the transformer neutral trough the earth as part of the normal earthing system. The explanation in this video only applies to common household installations in North America, but not to a big part of the rest of the world.
Finally someone that posted this very important difference between the earth systems used in different parts of the world. I was very confused by the fact that in many youtube videos they say that during a ground fault electricity goes through the neutral back to the transformer whilst in others they say that current goes through the ground wire to the ground copper rod. It would be really nice iff the author of the video fixed this comment so people can be aware of the differences.
Just sent this to my foreman because I believe I tried to describe this to him today and he said if something goes on the ground it goes to the ground rod so thank you for clearing this up for us .
Great explanation. One little bit worth considering is, even touching a neutral wire on a circuit has the potential to cause an unpleasant experience. Cause current takes every path back to source.
Under normal circumstances this is false. Only true when neutral is floating or disconnected. A lights neutral will become live for example. True neutral will not shock you.
@@Deiphobuzz yeah. I probably gotta stop thinking of less then ideal situations so much. But I mean more along the idea, for example, that if you touch a neuteal in an active circuit a person can become another path back to source. Not that this should be able to normally occur.
I am an Electrical Engineering student in senior year and I’ve been taught in such an amazing way like this before, I don’t even know if someone told me about basic information like this in college. Keep it up you are really doing something great for us.
To sum up. 1. We need a return path or closed circuit for OCPD ( circuit breaker or fuse) to shut off power. 2. All current (normal and fault) returns to origin but earth is not an effective conductor. 3. Instead we install our own path, as a green wire throughout electrical system. 4. That green wire jumps back to the neutral only once: at the service (disconnect). We don't want fault current going everywhere giving us noise, being a hazard, and parrelling paths which weaken it to not turn off OCPD.
As I've been taught. Ocpds like circuit breakers and fuses are installed to prevent fires and equipment malfunctions s. Its primary goals are not to save lives. This is why we have gfci s
In Norway we have 3-phase 230v only, for most houses and buldings, with no neutral wire. Here electricity actually returns to ground/earth rod when a ground fault happens. Thou the rest of the continent (not Norway and Albania) i belive use 400v ( 3-phase 400v + 1-Neutral + Ground ) as standard
@@wouterbos3 only a few costal areas in Norway use 230v TT The main standard in Norway is 230v IT (Isolated Terra) But some new buldings in recent years now use 400v TN (Terra Neutral)
Partially yes, with some editing to clarify some additional points. Problem is, people couldn't find this when they searched because it's buried within another topic. So this help people find exactly what they need. Additionally, it will earn a little extra money which we can use to fund new videos and help us bring you more free content.
Ok, so I understand all of this, thank you for taking the time to explain it all in detail! Now my question, that none of my electrician bosses can answer, if the neutrals and grounds are connected to the same bus why does the ground not carry any current if the neutral returns current to the same bus the ground is connected too?
The long version... lol In order to have current flow, you have to have a complete circuit between the power source, through the wires, and back to the other side of the power source. The ground wire is connected at one end to the neutral conductor, thus to one side of the power source, but it has no connection to the other side of the power source, and also no connection anywhere else to the neutral wire, and so no current can flow. This is actually exactly why the ground and neutral are only supposed to be Bonded at a single location, because if you had the ground wire connected to neutral at the main panel and also at an outlet you would get some current flow on the ground wire, because it basically becomes part of the neutral circuit, and that's not good! For one thing when you have current flow in a conductor, due to resistance you have differences in potential along the wire, and so some parts of the ground wire would now have a voltage difference when compared to say the water pipes, leading to shock hazards. This is part of the reason for the ground rod at the house, which will also be bonded to the water pipes, it's to achieve what's known as Equal Potential, where the neutral wire, and the ground wire, is at the exact same voltage as the water pipes and the dirt. And the ground rod at the transformer bonds the split phase windings to force one side of the transformer to be at the same potential as the earth. If you leave the neutral floating on a transformer, then you get 120v or whatever between the terminals, but you don't have one that's at 0v in reference to the ground, it floats. One site I was working on some industrial controls in an equipment room, and I was there after dark one day and discovered that there was 110v on the ground buss in the plc cabinet after I melted the end off a screwdriver lol I found that there was 0v from the "Hot" wire to grounded objects like water pipes, and 110v on the neutral and ground wires. I started testing but didn't find anything that night, so the next day I was going to start tracing the whole system back through the breaker boxes, but when I got there, everything was correct! I was confused, until a later day I was there late and around dark I heard a loud clunk, and curious I checked, and the voltage had flipped. Then I realized that some big outdoor lights were powered off the 110v panel, and so I started turning breakers off, and finally discovered that when I turned the breaker for one of the lights on, the voltage flipped. I discovered that the light circuit was dead shorted when the photocell energized it, so I disconnected it until it could be replaced. The room was served by a 3 phase feed, and they had put a transformer in the room to derive 110/240, and when I pulled the panel off, sure enough, the electrician who installed it had not bonded the neutral, so it was floating. That meant that when the "hot" side was shorted to ground, rather than tripping anything, it just referenced the whole transformer, and everything on the sub panel, so that hot was at Ground potential, and thus ground and neutral were now at 110 v to ground. I called the site rep over the next day and told him the problem, but he tried to tell me I was crazy, so I put the meter between the ground buss and the metal building, and took a test lead and hooked it to a screwdriver and the metal building, and jabbed the screwdriver into a live outlet with him yelling at me to stop, and then told him to look at the meter... I had to walk him through bonding and what was happening, but finally he agreed to call their electrician to come in and wire the transformer properly.
@@EngineeringMindset By the same token, if neutral and ground are connected to the same bus, why are two separate wires needed? Why can't the metal casing of an appliance just be connected to neutral?
@@Bapuji42 because it serves two different purpose. Neutral wire for return path on normal conditions, and ground wire for fault condition (hot wire touch metal case) If metal case connect to neutral then the metal case can shock human anytime.
the rule appears to be that you should never connect ground to neutral anywhere else than at the main panel. The reason for that (from countless individuals/websites online) is that once you do that, you would be a using a device's ground and neutral returns in parallel, and once the ground in a system is energized, this effectively energizes all other objects connected to ground in the system. But given that ground and neutral are already connected together at the main panel, doesn't that do exactly what is meant to be prevented with this rule? Once you have conductors (ground/neutral wires) at equal potential somewhere in the system, how does connecting them elsewhere change their relative potential?
Nice video. Please break this down even further to the lead common denominators. In some ways very siimple but with multiple scenarios its complicated.
I was horribly misinformed on this subject in high school. It's a shame the misinformant still collects a salary and benefits. You've gained a new subscriber.
Many thanks for all the videos you do they're always educational. Question with regards to this one though, when you say the ground fault will takes preference over the path with the least resistance and therefore take the ground - neutral path instead of the ground rod. Surely this is incorrect and it will take both routes back to the transformer? Isn't it just a parallel path for the current one with high resistance (the earth rod back to earth rod at the transformer) and one with low resistance (ground wire - neutral back to the transformer) and therefore it will take both paths? Many thanks in advance 🙂.
I'm throwing out some arbitrary numbers here, which I'll explain in a moment. The ground to neutral route has a resistance (impedance) of 0.1 ohms and the ground to earth to ground to neutral route has a resistance (impedance) of 100 ohms. Even though it's a parallel circuit, a thousand times more current travels through the neutral to ground route. In reality the impedance difference is usually much higher, but it depends on the impedance of the earth, which varies wildly depending on conditions. If the soil is saturated with salt water from a hurricane surge, that might just become the path of least resistance! Study the topic of resistor networks.
@@jstreutker and therefore takes both routes back to the transformer regardless of resistance? Just that in the video he states that "as we already have a very low resistance ground wire which provides a path directly back to the source, the ground fault is going to take this route instead" which in my opinion was an incorrect statement because as you've just said that if the soil becomes saturated with salt water from hurricane surge that might just become the path of least impedance. So in any scenario the fault current takes all paths back to the transformer and not just the path with the least resistance, which was my initial question and my understanding of it. 🙂
@@stevenhargreaves9897 you are correct that electrons take all available paths, which is why the ground and neutral circuits are only allowed to be bonded at a single point, otherwise the ground wire would have varying potential along its length since it would be a parallel current path. So yes, a fault circuit that includes contact with the earth as well as the ground wire will return some current through the earth, and so the statement in the video is inaccurate. In practice it doesn't make much difference, because even with a salt water soak, the impedence of the soil will be so much higher than a copper wire that negligible current will flow, but it may be enough current to stop a heart, so that's why we use GFIs etc. So yes, that should be worded differently, but it's relatively minor in the scheme of things. The main purpose for the ground wire is to get a high enough fault current to trip the breaker, because through the earth is basically never enough current to trip a breaker and stop a fault.
@@ke6gwf Many thanks for your reply it is much appreciated. Yes I understand that RCDs or what you call GFIs are used to trip when there is a current in excess or equal to a certain amount (typically in the UK 30mA) flowing to earth. When you say that ground and neutral circuits are only allowed to be bonded at a single point, otherwise the ground wire would have varying potential along its length since it would be a parallel current path. In the UK we sometimes use a certain type of earthing system called a TN-C-S which sometimes incorporates a PME which refers to Protective multiple earthing. This is where the combined earth/neutral conductor is connected to the physical ground in multiple places along the cable length. Would this be a case where there is multiple ground and neutral circuits and therefore it will have varying potential along its length? So from the point where the neutral and earth are combined they run all the way back to the transformer, then all the high resistance earth electrodes are each parallel paths back to the transformer? I hope this makes sense and apologies if you are unfamiliar with this type of earthing arrangement I'm not sure if where ever you're from uses this type and I'm assuming you're not from the UK when you referred to what we call an RCD a GFI. 🙂
I learned a lot from this video. Thank you. Question: In the sub panel, neutral and ground will not be bonded. In that case, where would the Fault current will go?
Depending of what type of grounding system you have, the ground rod can actually be used for fault currents. In my area, we dont get ground from the services. Nor is neutral connected to our ground wires. We call that TT. What you describe looks more like TN.
I believe this video was geared towards the U.S. (We don't do TT installs here to my knowledge). We are strictly TN-C-S but we don't call it that. We call it "multigrounded neutral" (MGN) because we have to have our own terminology for everything, lol
The most important life saving practice is ALWAYS de-energize the circuit for the components you are working on. That’s the best way to not get electrocuted.
Smashing video. Can you do one on earth leakages caused by chillers, drivers, pumps, pfc, motors etc. we have this problem at work. We had 12amps at the MET. Found a loose PME rod. Rectified it and the earth leakage dropped to 9 amps . Turned the chillers off, the leakage went down to 7 amps. Checked the transformers star point and it's OK . Check all terminations. Still no answer
Check all your neutral connections to as close back to the supplying transformer that you can. A bad / loose neutral will allow more current to flow through the ground to get back to the source. There should be no good reason to have ground leakage measured in full amps, milliamps, yes. Either a device is seriously damaged or, in your case and especially since it changed with varying the load, a bad neutral somewhere from the panel back to the supply. If you have to, have the power company check the connections on their end as well.
@@inothome I had, what appeared to be, a 'floating neutral'. Lights would flicker, dim, surge, all hours of the day and night. No correlation to any high-current devices. They did high-current tests between the pole and my panel, all checked out fine. I had the power company out 3 times. Each time they insisted it was something in the house. I tightened every screw in the panel myself, still happened. I tried shutting off different circuits, didn't matter. I had a licensed electrician come in and RE-check all my screws, connections, breakers--still happened. Paid to have them out twice. On the 4th time out, the poco tech said "I'll change out a few things at the transformer, see if that helps." Not sure what he changed, but it fixed it immediately. I had this, intermittently, for 3+ years. It took that long for the power company to actually fix it. They just kept denying it was their issue. Meanwhile, I spent a small fortune on tools, replacement breakers, electricians, checking every outlet box in the house... Infuriating. And can be really dangerous! So my advice: Check everything possible in your walls. But don't rule out a bad transformer or service problem.
This is why GFCI breakers and receptacles are so important. If you DO get across the hot side wiring the GFCI detects the ground current and trips the breaker almost instantly. GFCI breakers can be problematic in some situations.Exterior Christmas lights are good examples. If they get wet with rain or snow, they can trip GFCI breakers and GFCI outlets.
0:00-0:09 That’s true for half a cycle (that current flows from the source to the load through the live wire, and from the load to the source through the neutral wire). In the other half cycle, it’s the opposite: current flows from the load to the source through the live wire, and from the source to the load through the neutral wire. I suppose you didn’t say this because you usually use DC for explaining AC circuits. But I thought I’d clarify this because many other people say what you said without specifying that’s true only for half a cycle.
@@altuber99_athlete True enough about the actual current flow, But I agree with the way it's done in the video as it's less a less distracting way to illustrate the concept of grounding, esp. if the viewer is new to the subject and want's to know why the ground wire is important. I've seen films in the past that did the opposite. in a 1950's (?) film demonstrating simple circuits a battery, a switch and and several light bulbs were used for the visuals, but every time a circuit was demonstrated a 60Hz hum is heard. For the first few circuits, I could not figure out WHY a DC circuit would have a hum. It could not have been a simple indicator of the circuits working as a lit bulb (or bulbs....) would be enough for that. THEN they showed various way a SHORT circuit could occur, then I got it. They wanted to have a way to indicate that current flowed in a short no matter if no bulbs were lit. It was just to make it so a layman would understand.
@@jamesslick4790 Okay that's fine. Perhaps The Engineering Mindset should have clarified later in the video (after explaining ground), that current changes direction and thus for half a cycle it flows from the load to the source through the hot wire and from the source to the load through the neutral wire.
Every person watching this needs to understand that the service entrance ground bus is the ONLY place the bare ground and the white grounded conductor can touch. Anywhere else and you create multiple fault paths and a dangerous ground loop situation. One of the most common wiring errors.
@3:00 Today's houses have the ground connection connected to the neutral before a differential circuit which senses the difference bw neutral and hot currents. Thus you cannot die, as soon as the difference is > 0 the circuit stops the flow of current in the house.
I studied engineering in undergrad and I still don’t understand this stuff. I’ll rewatch this another time, but I’ll probably have to draw this stuff out myself to understand it.
If I may offer a bit of feedback: The video starts very abruptly with the ENTIRE THING shown. The whole image is animated, so the viewer has difficulty orienting themselves in it. You do not highlight what you're talking about with some bright frame or spotlight, and the animations keep switching without being synchronized with what you're talking about. I'd recommend first establishing what's on the screen, with several sentences such as "On the left side, you see the electricity producer's transformer which converts [x] to [y]. From there, wires bring electricity inside someone's house or an office building. On the right is the electrical socket in the wall." etc.
Thanks for feedback. This video is literally just a snippet from our long video about the electrical system. Please watch that "Electrical panel basics" or "120 & 240V electricity explained" for full explanation
That System really remembers me on the fail-safety systems in my country. We use something called "die Nullung" It's a modern version of the old Nullung ss it have some math stuff and more preparation What it does: the system builds on breakers. Your electricity must be build, thst the breaker will be for sure cut down the wires. Like: if you want to use a breaker LS-Typ B, then you need to get a currency of I×5 So if the breaker can hold 10A, then your system needs to get in worst cases everywherr 50A or more Too that their are 2 or 3 other rolds, like grounding and so, that needs to work
The cables going to the ground rods are considered grounds. The wires used to connect metallic parts of the devices in the electrical system are bonding wires.
lovely as usual but this time it's hard a little bit to understand because the distraction of eyes in so many items in pictures shown unlike some previous videos were so simple cuz few itmes in pictures and deeply concentrated ,, specially of non english speakers like me :)
The resistances of the ground wire at the outlet is no less then the resistance of the neutral wire. The current flowing thru a device and then back on the neutral doesn't trip the breaker because the device acts as a resistance item, aka resister, and doesn't allow the current to flow thru the device to over load the breaker. You can remove the neutral and connect the ground wire to the neutral connection and it will not trip because the wire has the same resistance as the neutral. In return you can connect the neutral wire to the case of a device and it will properly function as if it was a ground wire. In either situation if the hot wire touches either the ground wire or the neutral wire with no load connect in between, but a direct connection it will trip the breaker as a direct fault.
The question nobody seems to be able to answer is... why two separate wires? They're shorted together at one end, so isn't one of them redundant? Why not just, as you say, have the neutral wire connected to the case?
@@Bapuji42 Because the neutral wire carries current, the ground wire only does when there is a short. So if for example you was using a hand drill with a metal case, assume the neutral attached to the case, you can hold the case and with the drill off and be fire. Turn on the drill and now the case has current running through it and the your hand. if the resistance to ground is less through your body then through the neutral wire you will get shocked. Now if a ground wire is connected then you can use the drill and have short circuit protection without risk of getting shocked because the ground wire only carries current on a direct short which would trip the breaker instantly.
@@johnchase7667 That makes sense, thank you. I thought of another reason. If something happened and there was a break in the neutral wire, everything attached to neutral "upstream" of the break would be at the same voltage as hot, since with no current flowing there's no voltage drop across any load.
This is just a bonded ground and neutral situation. In europe we mostly use a terra terra setup, the ground is not bonded to the neutral. Or you get a separate ground and neutral wire delivered from the net.
Is the central mystery "Electricity always tries to get back to it's source" ? This always seems to be the final simplex statement that concludes even the most edifying of descriptions of circuits / grounding. Is there no way that equivalent power and application of electricity could be found by something equivalent to a giant over-charged balloon running to a different probably impossibly humongous under-charged balloon?
Great Video. I would have added Bonded and Unbonded panels into the mix. Since people like to add addition's to House's, Garage's, Shops, or Man Cave's. Or maybe I missed that video.
Thankyou for this video but it would be best if you could give green clr to the ground line as it would be more clear + it’s what is used for grounds. Thanks
Ah nice video. The 3 wire design in home electrical always confused me a bit, likely because I learned how to do electrical work on cars which use a 2 wire system and different terminology.
Thank you so much for these videos! Is there any explanation as to why the ground has a lower resistance? Usually all the wires are copper. What's the difference. TYIA
@@EngineeringMindset Thank you for the answer, if I can add to my question I would appreciate it. I didn't see in the video how the ground would trip the breaker. I don't see any physical connection from the ground to the breaker. Thank you for your time. Edit: Unless since this is AC there would be high current going back through the hot wire causing the trip.
Thank u very much I like yo channel so much hope u wd one day make for me videos of powerful amplifier coz I like to learn how to make them so much God bless you
⚠️ *These videos take a long time to make* if you would like to buy Paul a coffee to say thanks, link below: ☕
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Thank 🙏🏻🙏🏻🙏🏻🙏🏻🙏🏻🙏🏻🙏🏻 we must respect who ever who teaches us something
Thanks for your reply Sir hope I would one day buy a coffee
mo_st1
Thank you for the useful information
To murky up the waters more, the hull of most (metal) ships is.. is usually the connection point to all grounds.
Those first 30 seconds really cleared up 80% of my questions about grounded wires. Thank you
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ruclips.net/video/Qi0ynSQw-wc/видео.html
same
This is fantastic. This is such a murky subject for even experienced electricians. This explanation is so clear, love it!
Ground is hot that's how I remember it lol
It is scary to me that any electrician, much less an experienced one, does not already have a very good understanding of this.
Great explanation
@@bjarnedevos5891 how do you mean? I am curious.
100% agree. This is the basic stuff.
"This could lead to death" "Alright bye guys see you in the next video" best way to end a vid
if there was a RCCB in the panel, would the persons life be saved?
@@nitro-ww6sk Yes, most likely.
Glad there was a happy ending to the video
@@stefannilsson2406 Ya I am surprised that ELCB/RCCBs are not standard fixtures in the home US electrical distribution panels. Who would have thought that making sure that the making sure that current leaving the live connection should equal the amount of current returning through the neutral for the whole house would be a much better idea than to only have it in the bathrooms
I love how the workman in these videos always has a big smile on his face right before he gets electrocuted :)
Pretty realistic, that's usually how it goes.
😃 ⚡ 😵
I love these short educational videos, they are very easy to follow and grounded in simplicity 😉
I see what you did there
@@EngineeringMindset laugh out loud!!!
😂
This is all the information I wanted to know. Why is it so hard for someone to answer this for me when I ask it. This video is short and to the point and I wish everyone would explain things this way. Thank you
The Internet acts like only electricians or people trying to mess with things around the house they maybe shouldn't are the only people trying to learn about electricity
I don’t get it
It’s only for emergencies instead of the current going through you, it goes through the ground wire.
It’s just for emergencies so the current goes through the ground wire instead of anything else that touches it including you.
@@llamaface6229 I understand the concept, not the explanation
You don’t need to understand it. Just turn off the breaker before doing any electrical work 😂😂
Then don’t work on anything electrical 😅
How about a video on most common ways people get hurt by electricity and how to avoid it. Thanks!
Good idea, my shock was from touching an intermittently live wire.
Most common way people get hurt is by touching live wires 😅
@@EngineeringMindset I was recently shocked by an electric iron🥺.
#1 cause: by being alive, easilly avoided by using time travel to give your dad a condom/swift kick to the goolies.
disclaimer: this is not legal advice. condoms are not 100% guaranteed to work; I hold no responsibility for accidental discovery of infidellity. time travel may cause motion sickness, fatigue, dorcelessness, etc. so consult -the- a doctor about it first.
How to avoid it? De-energize every circuit before you work on it, make sure you understand grounding (as explained in this video), make sure you ground all your circuits, make sure everything is safe and all people and animals are not touching the circuit before you re-energize it (lock out/tag out). Pretty basic concepts, I think.
Wow. 1 year of Electrical training and this video definitely helped more than anyone else XD
This reminds me of a terrible incident here in Australia a few years ago where a young girl received a shock from the house's ground wire. The family had complained to their housing authority for a long time that the electrics in the house were faulty. The girl had gone outside to turn a hose off, barefoot, and received a shock from the ground wire. She survived, but can no longer talk or walk - I'm not sure how much she's recovered since. I always wondered how one could receive a shock from the ground wire, since I always thought *it* was the 'safety feature' - but I see with a large enough fault they can be carrying dangerous current.
Dumb family was waiting for ‘authorities’ to fix electrical problem in their home?!?? What happened to hiring an electrician? Well - pity their daughter had to pay the price for their empty heads and scroogyness….
J
J
That is, at least as far as I heard, exactly why in Serbia it is forbidden to use a TN system in houses. I think many old ones still are TN but a lot and even mine from 1976 has (tested) good earth rod so it is very easy to switch to TT.
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ruclips.net/video/Qi0ynSQw-wc/видео.html
I own a engineering business. I went to use my tig welder ( set on 180 amps ), after starting to weld the setting seemed very low on current. I stopped & checked that the machine was set correctly & started welding again. The current was still low but now there was a burning smell & smoke in the workshop. After a bit of investigation, I had left the earth lead for the tig welder on another steel bench , but I was welding on a jig that had a 3 phase drive motor. The earth circuit went through the frame of the jig , the 3 phase motor, out to the earth stake , back to the bench grinder on the other welding bench ,into the earth lead on the bench. The smell & smoke was the lead for the bench grinder, as this was the smallest wire in the circuit & couldn't handle 180 amps it melted .
U own an ‘engineering business’, but you are a welder? Somethings doesnt make sense here
@@zefrum3 Just because you own a business doesn't you sit back & dont work.
@@robertsomerville5377 well hmm… *sighs*. Where to begin… Read carefully: You are not an actual Engineer if you are the Welder.
@@zefrum3 nowhere did I say I was an engineer, I said I own an engineering business.
@@robertsomerville5377 okay…so not an engineer but you own an engineering business. Please explain, b/c thats like a non-Doctor owning a Doctor’s Practice and playing around with the Patient’s files…
This is actually one of the easiest videos to understand. I love that it’s 3 minutes.
I held my breath through this, waiting for the big fatal mistakes, but I didn't find any! Good job lol
There was one minor one and an oversight. The ground rod isn't only to dissipate static, it's what references the entire ground and neutral system to be Equal Potential with the dirt, and also the water pipes, building frame etc. You didn't mention how the ground rod is also bonded to the water pipes for this reason.
And when you said that the fault current will travel back to Source via the ground wire INSTEAD OF through the earth, that's incorrect, it takes both/all available paths, so some current will flow through the earth all the way back to the power plant itself. It will be very small, and if you hook a wire to a ground rod and connect a hot wire to it, you won't trip a regular breaker so little current flows, but SOME current does flow.
But still, you give a better explanation than most people ever have lol
Hm, i have a question then:
If the neutral at the transformer is sticked into the earth (ground rod) and also at my house, and that has a very high impedance, how is then the current able to pass my body when i touch the Live wire?
It should actually harder since in most cases i dont have a direct connection to dirt where it could flow back to the transformer or even my houses ground rod.
What happens here then??
We use a grounded neutral as a 0v reference in controls. Sometimes ill measure control voltage to a pipe. Because why not.
Sorry should be more specific, grounded neutral of a 24v transformer
@@gandalf1783 if you are insulated and touch a hot wire, nothing happens.
Just like a bird sitting on a power line.
However, moisture is present in a lot of things, and most shoes are not completely insulating (sweat from the foot combined with pinholes in the sole etc), and so electricity can often find ways back to Source.
For instance, if you are standing on bathroom floor after someone took a shower, the floor might have enough moisture on it to make a current path to a ground-bonded water pipe.
You can also simply touch both terminals on an outlet.
Or on carpet, if the humidity is high enough there might be some conductivity, or maybe you are kneeling on a nail beneath the carpet and the board has some moisture because the crawl space has high humidity, and the board is grounded to the damp concrete foundation.
However, if you are wearing dry shock hazard shoes which have a dielectric barrier in them with no pinholes, or you are standing on a dry rubber anti shock mat, a clean and dry fiberglass ladder or plastic stool, then you can touch a hot lead with no shock, because there is no where for the current to go.
All of the situations I mentioned before are very high impedance circuits, but it takes so little current to be dangerous to us that we can still get that shock.
Now, I have gotten a lot of shocks in my life, between faulty equipment (not my fault) and working with electricity (my fault lol), and most of them were more straight forward, standing on wet surfaces, or touching both sides of a circuit, like the time my hand slipped on a large motor starter overload reset button and I punched across the 3 phase 480v terminals with my knuckles.
I was actually standing on wet metal when it happened, but I had dry boots on so the only shock I got was between phases across my knuckles.
I also was in the habit when I was working on open control panels like that to keep one hand behind my back, which may have saved my life that time, because if my other hand had been holding the cabinet door at the time it would have been much worse.
I had an old electrician friend who used to never put cover plates on at his place so he could test the power easily if something went out, and he had to lick his fingers to be able to feel 110 v lol
And usually he had to touch across both terminals or touch something grounded, because he would not be grounded standing on dry dirt or concrete.
But it's hard to tell for us normal people whether what we are standing on is indeed dry enough to insulate us from ground.
this a 3 min video, you are more than welcome to create content, this is over simplified for the sake of education lmao he wasnt gonna take EVERY what if just for people like you that likes to complain about everything jesus
You are correct but it goes further!
The "Ground Wire" connects different areas so they are at the same potential. This is most evident at the star point on a transformer. The star point is the source of the Neutral connection AND is bonded down to the body of earth, so if you touch a Neutral whilst standing on the floor there is no potential difference, no Voltage and therefore no current will flow!
The services in your home and workplace also have an Earth point where the Gas and Water pipes are connected together (there may also be cross bonding at your hot water tank, boiler and sinks). This means that All "Earthed" points are at a similar potential.
This may seem obvious but if you have adjoining properties that are fed from different substations there can be a potential between different lives (even on the same phase) and it is the earth connection down to the body of earth that keeps this to a minimum!
It could have been worded better though. He states that electricity "prefers" to travel thru a low resistance path (here a wire rather than the actual earth), but electricity will take ALL paths, the current will be higher in the lower resistance one.
eg if you put a 1 ohm & a 1000 ohm in parallel across a power source, both will carry current. The 1000 ohm will only have 1/1000 of the current that the 1 ohm resistor does, but it's not zero.
@@j.f.christ8421 he was right as far as electricity will indeed be highest at the very least path of resistance
....and its funny its called ground....because in fact they are also talking about the ground we walk on
@@edwardscomputers No coincidence! We call it Earth in the UK. Could be worse though .... how about the Dirt Wire? ;o)
@@edwardscomputers The way he said it inferred that it ONLY goes thru the low resistance path. It's a common statement "electricity goes thru the path of least resistance", which is true but it ALSO goes thru the high resistance path(s).
Correction: Current takes all paths. If it took only the least resistive path then parallel circuit wouldn't exist. Yes, less resistive paths cause currents of high magnitude and high resistive paths lower the current's magnitude. That's it.
Not for engineers.
Engineer: it's close enough, make it zero 😉
Also, PI = e = 3
Current takes the path with the least resistance always. But it doesnt mean it has to go in a single line. Its path can be devided and make it even less restrictive. Electricity is just moving electrons. So if they ALL go in the less restrictive path it becomes more restrictive than splitting 80/20
Here in The Netherlands, a ground-wire is green-yellow. Also, most houses only have a ground-wire connected in the ''wet-rooms'', bathroom, kitchen, garage(sometimes), but not in the living room, bedroom etc.
Here in america it's standard for all receptacles to have a ground wire and a third prong to provide equipment ground. Y'all most likely have full-house RCD/GFCI protection, which isn't standard here, though we're getting more and more GFCI/AFCI requirements as the years go by.
Wtf, not in every room? In Germany it is.
Nonsense. PE wire everywhere and earth rods were becoming standard in Yugoslavia by the 80s. You can't tell me Western Europe had worse safety standards than us.
I've had desktop computers before with crummy power supplies that would shock you when you touched the case. Grounding was the solution in these situations as it allowed this stray voltage a path back to panel neutral.
That should trip your rcd
@@stevecarter8810 Panel's only used standard U.S. style circuit breakers. Not enough current flow to trip the breaker. Probably a current flow of 500ma or so.
@Fransisco Wijaya True. Fortunately for me that place was all utilities paid haha!
And you kept those in your pc?? Brave man!
(are you sure it wasn't just static buildup on you? Wool sweater, socks on laminate floor, that kind of thing... )
That is not a sign of a bad power supply that's a sign of a GOOD power supply. It means you have a noise filter and these filters leak a few mA to ground. In my grandparents house from the 60s that had no PE wire on most or all outlets I would get a zap from touching a computer case or even metal keyboard with even slightly wet fingers. It is because of this. Doesn't help it was all on one power strip so all other switch mode PSUs with filters were adding more current to the earth wire that went nowhere.
This is a great video I can share with my customers who are confused by someone saying they're system is ungrounded.
I suggest you find simpler explanation.
This explains "how" but not "why"
I'm glad you ended that on an uplifting note.
the first time I watch a RUclipsr answers my question in the first 30 sec thank you
This is great. Thanks for posting. As I suspect,al along with a lot of people, I had an incorrect understanding regarding how this works.
Electricity takes all paths, not just the "path of least resistance." It has no way of knowing ahead of time which is the lowest path of resistance. The percentage of total current in a conductor within a circuit is proportional to its resistance.
All of this guys videos are really great! All you have to do is look at some of the other videos on various subjects to know that Tom’s videos all excellent, uniform, and a super great resource for learning said material. Definitely one of my favorite content creators on electrical subjects!
Sir, with due respect, "path of least resistance" is incorrect. The reason for ground conductor having low resistance is for the ckt breaker to trip faster due to having higher current during fault condition. Everything that is in parallel with the circuit still has current flow but just in proportion with its resistance.
Appreciate your very informative presentations, still. 👌
Correct, electricity doesn't take the path of least resistance, it takes ALL PATHS of resistance, even in a "dead short" since no matter what everything has some kind of resistance.
He did however say "preference of path of least resistance" meaning technically majority flow but even so he should have clarified it
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ruclips.net/video/Qi0ynSQw-wc/видео.html
I'm always with Engineering Mindset
Shout out to the ground wire, out here saving lives. I never knew that's what they were for.
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ruclips.net/video/Qi0ynSQw-wc/видео.html
Excellent...my mind is relaxed after watching this video... before watching this, elecron fl ow , grounding etc is a black box for me... thanks for the efforts in making this video... please make more
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ruclips.net/video/Qi0ynSQw-wc/видео.html
Thank you very much! I felt like you made this video just for me. My washing machine gave me a bit of a shock when I touched the water and I wanted to ground it (pun intended). I only knew so little and this was the first video I opened, and to my surprise, you used washing machines as an example.
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ruclips.net/video/Qi0ynSQw-wc/видео.html
I appreciate a split-phase diagram being used for this, being from North America. ;)
This way of how grounding works (from the grounded component earth wire through the neutral line back to AC transformer) ONLY applies to specific TN-earthing systems (TN-C and TN-CS).
It does actually not apply to TN-S and TT earthing systems, used in Europe and Asia (and US at gas stations ect. by exception).
In a TT-earthing system (common in Europe) the return fault current actually IS returned by going trough your premise ground rod trough the earth to the distribution AC-transformer ground rod connected to its starpoint or neutral wire. There is here NO link between the neutral line from the supply at your premise to the grounding/earthing wires in your installation. Because of the higher resistance of the earth soil the current will in a lot of cases not be high enough to trip your normal circuit breaker (overcurrent protection) while still being deadly dangerous. Therefore a RCD/GFCI-device covering your entire installation at the supply is mandatory in most countries, as it will trip much faster at a the existence of a ground fault current of 300mA/30mA.
When in a TN-C earthing system the neutral gets broken (by heavy weather at power poles for example) you get a dangerous situation because (1) the only return path is trough the soil with higher resistance and the installation does not always have a general RCD covering the entire installation and (2) with the lack of a neutral conductor the devices connected between the 2/3 phases and the in-house neutral are getting connected in serie leading to a dangerous abnormal high voltage on your 'grounded' equipment. Using a PEN-conductor (combined neutral and protective earth condictor) as in this video can be really dangerous if the PEN-conductor is broken upstream. In the UK/Australia this setup is called PME (Protective Multiple Earthing), but it basically the same as TN-C-S with additional ground rods along the way to reduce the electric potential created by the PEN-conductors themselves because of the long distances/resistance of the cheap conductor materials used.
So based on your earthing system, the ground rod at your premise is besides lightning strike protection possible also used as a conductor back to the transformer neutral trough the earth as part of the normal earthing system.
The explanation in this video only applies to common household installations in North America, but not to a big part of the rest of the world.
Agree, the video is for North America only
Finally someone that posted this very important difference between the earth systems used in different parts of the world. I was very confused by the fact that in many youtube videos they say that during a ground fault electricity goes through the neutral back to the transformer whilst in others they say that current goes through the ground wire to the ground copper rod.
It would be really nice iff the author of the video fixed this comment so people can be aware of the differences.
I thought TN-CS is also common in Europe (not sure about Asia tho). TN-S is too expensive
Just sent this to my foreman because I believe I tried to describe this to him today and he said if something goes on the ground it goes to the ground rod so thank you for clearing this up for us .
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ruclips.net/video/Qi0ynSQw-wc/видео.html
A down to earth explanation if you will. Great video
I see what you did there.
@@anthonyjagers7770 great minds think alike
Great explanation. One little bit worth considering is, even touching a neutral wire on a circuit has the potential to cause an unpleasant experience. Cause current takes every path back to source.
Under normal circumstances this is false. Only true when neutral is floating or disconnected. A lights neutral will become live for example. True neutral will not shock you.
@@Deiphobuzz yeah. I probably gotta stop thinking of less then ideal situations so much. But I mean more along the idea, for example, that if you touch a neuteal in an active circuit a person can become another path back to source. Not that this should be able to normally occur.
Paul I learned a lot from you and keep making videos
Absolut awesome videos! I love them because they are so clear and dont loose you even if you are a beginner.
Appreciate the info and illustrations. Working to my goal of being able to build my own house!
Get some permits
I am an Electrical Engineering student in senior year and I’ve been taught in such an amazing way like this before, I don’t even know if someone told me about basic information like this in college.
Keep it up you are really doing something great for us.
@ Mahmoud : Did you mean to say you've *_never_* been taught in such an amazing way like this before?
@@Milesco yes, I got terrible teachers in my freshman years 🤣
and I am trying learning some miss-understanding concepts myself now
glad you finished this video with a very happy ending scenario
Always end the vid on a high note……”you are dead”
More please!
To sum up. 1. We need a return path or closed circuit for OCPD ( circuit breaker or fuse) to shut off power. 2. All current (normal and fault) returns to origin but earth is not an effective conductor. 3. Instead we install our own path, as a green wire throughout electrical system. 4. That green wire jumps back to the neutral only once: at the service (disconnect). We don't want fault current going everywhere giving us noise, being a hazard, and parrelling paths which weaken it to not turn off OCPD.
As I've been taught. Ocpds like circuit breakers and fuses are installed to prevent fires and equipment malfunctions s. Its primary goals are not to save lives. This is why we have gfci s
A good explanation on AC. DC is much different and simpler
In Norway we have 3-phase 230v only, for most houses and buldings, with no neutral wire.
Here electricity actually returns to ground/earth rod when a ground fault happens.
Thou the rest of the continent (not Norway and Albania) i belive use 400v ( 3-phase 400v + 1-Neutral + Ground ) as standard
Indeed. All installations with TT earthing use the earth soil as a conductor, which is in combination with a RCD/GFCI perfectly safe.
@@wouterbos3 only a few costal areas in Norway use 230v TT
The main standard in Norway is 230v IT (Isolated Terra)
But some new buldings in recent years now use 400v TN (Terra Neutral)
Clear concise information as always. Some will find it difficult
to accept the current not going to the ground rod. Thank you
Partially yes, with some editing to clarify some additional points. Problem is, people couldn't find this when they searched because it's buried within another topic. So this help people find exactly what they need. Additionally, it will earn a little extra money which we can use to fund new videos and help us bring you more free content.
Nếu mà bị cháy đường truyền thì sẽ như thế nào
I'm glad the man being shocked no longer looks happy while he is being used a a ground path.
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ruclips.net/video/Qi0ynSQw-wc/видео.html
Ur graphics insanely help with ur description of the subject. I will make a statue in ur name one day.
Your explaining and animation skills so good😏😏
Ok, so I understand all of this, thank you for taking the time to explain it all in detail! Now my question, that none of my electrician bosses can answer, if the neutrals and grounds are connected to the same bus why does the ground not carry any current if the neutral returns current to the same bus the ground is connected too?
The ground connects to the metal casing not the load, it will only carry a current if the hot touches the metal case
The long version... lol
In order to have current flow, you have to have a complete circuit between the power source, through the wires, and back to the other side of the power source.
The ground wire is connected at one end to the neutral conductor, thus to one side of the power source, but it has no connection to the other side of the power source, and also no connection anywhere else to the neutral wire, and so no current can flow.
This is actually exactly why the ground and neutral are only supposed to be Bonded at a single location, because if you had the ground wire connected to neutral at the main panel and also at an outlet you would get some current flow on the ground wire, because it basically becomes part of the neutral circuit, and that's not good!
For one thing when you have current flow in a conductor, due to resistance you have differences in potential along the wire, and so some parts of the ground wire would now have a voltage difference when compared to say the water pipes, leading to shock hazards.
This is part of the reason for the ground rod at the house, which will also be bonded to the water pipes, it's to achieve what's known as Equal Potential, where the neutral wire, and the ground wire, is at the exact same voltage as the water pipes and the dirt.
And the ground rod at the transformer bonds the split phase windings to force one side of the transformer to be at the same potential as the earth.
If you leave the neutral floating on a transformer, then you get 120v or whatever between the terminals, but you don't have one that's at 0v in reference to the ground, it floats.
One site I was working on some industrial controls in an equipment room, and I was there after dark one day and discovered that there was 110v on the ground buss in the plc cabinet after I melted the end off a screwdriver lol
I found that there was 0v from the "Hot" wire to grounded objects like water pipes, and 110v on the neutral and ground wires.
I started testing but didn't find anything that night, so the next day I was going to start tracing the whole system back through the breaker boxes, but when I got there, everything was correct!
I was confused, until a later day I was there late and around dark I heard a loud clunk, and curious I checked, and the voltage had flipped.
Then I realized that some big outdoor lights were powered off the 110v panel, and so I started turning breakers off, and finally discovered that when I turned the breaker for one of the lights on, the voltage flipped.
I discovered that the light circuit was dead shorted when the photocell energized it, so I disconnected it until it could be replaced.
The room was served by a 3 phase feed, and they had put a transformer in the room to derive 110/240, and when I pulled the panel off, sure enough, the electrician who installed it had not bonded the neutral, so it was floating.
That meant that when the "hot" side was shorted to ground, rather than tripping anything, it just referenced the whole transformer, and everything on the sub panel, so that hot was at Ground potential, and thus ground and neutral were now at 110 v to ground.
I called the site rep over the next day and told him the problem, but he tried to tell me I was crazy, so I put the meter between the ground buss and the metal building, and took a test lead and hooked it to a screwdriver and the metal building, and jabbed the screwdriver into a live outlet with him yelling at me to stop, and then told him to look at the meter...
I had to walk him through bonding and what was happening, but finally he agreed to call their electrician to come in and wire the transformer properly.
@@EngineeringMindset Ahh, ok I get ya! Still seems weord to me lol bur I appreciate it!
@@EngineeringMindset By the same token, if neutral and ground are connected to the same bus, why are two separate wires needed? Why can't the metal casing of an appliance just be connected to neutral?
@@Bapuji42 because it serves two different purpose.
Neutral wire for return path on normal conditions, and ground wire for fault condition (hot wire touch metal case)
If metal case connect to neutral then the metal case can shock human anytime.
the rule appears to be that you should never connect ground to neutral anywhere else than at the main panel. The reason for that (from countless individuals/websites online) is that once you do that, you would be a using a device's ground and neutral returns in parallel, and once the ground in a system is energized, this effectively energizes all other objects connected to ground in the system.
But given that ground and neutral are already connected together at the main panel, doesn't that do exactly what is meant to be prevented with this rule? Once you have conductors (ground/neutral wires) at equal potential somewhere in the system, how does connecting them elsewhere change their relative potential?
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Love these videos. Thanks “Dad”
Very welcome
Thanks for breaking it down like that. I always thought that the buried ground was connected to the "appliance" ground lol
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Nice video. Please break this down even further to the lead common denominators. In some ways very siimple but with multiple scenarios its complicated.
I was horribly misinformed on this subject in high school. It's a shame the misinformant still collects a salary and benefits. You've gained a new subscriber.
Thanks for this. I took two electronics courses yet grounding was something I never fully understood.
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Many thanks for all the videos you do they're always educational. Question with regards to this one though, when you say the ground fault will takes preference over the path with the least resistance and therefore take the ground - neutral path instead of the ground rod. Surely this is incorrect and it will take both routes back to the transformer? Isn't it just a parallel path for the current one with high resistance (the earth rod back to earth rod at the transformer) and one with low resistance (ground wire - neutral back to the transformer) and therefore it will take both paths? Many thanks in advance 🙂.
I'm throwing out some arbitrary numbers here, which I'll explain in a moment. The ground to neutral route has a resistance (impedance) of 0.1 ohms and the ground to earth to ground to neutral route has a resistance (impedance) of 100 ohms. Even though it's a parallel circuit, a thousand times more current travels through the neutral to ground route. In reality the impedance difference is usually much higher, but it depends on the impedance of the earth, which varies wildly depending on conditions. If the soil is saturated with salt water from a hurricane surge, that might just become the path of least resistance!
Study the topic of resistor networks.
@@jstreutker and therefore takes both routes back to the transformer regardless of resistance? Just that in the video he states that "as we already have a very low resistance ground wire which provides a path directly back to the source, the ground fault is going to take this route instead" which in my opinion was an incorrect statement because as you've just said that if the soil becomes saturated with salt water from hurricane surge that might just become the path of least impedance. So in any scenario the fault current takes all paths back to the transformer and not just the path with the least resistance, which was my initial question and my understanding of it. 🙂
@@stevenhargreaves9897 you are correct that electrons take all available paths, which is why the ground and neutral circuits are only allowed to be bonded at a single point, otherwise the ground wire would have varying potential along its length since it would be a parallel current path.
So yes, a fault circuit that includes contact with the earth as well as the ground wire will return some current through the earth, and so the statement in the video is inaccurate.
In practice it doesn't make much difference, because even with a salt water soak, the impedence of the soil will be so much higher than a copper wire that negligible current will flow, but it may be enough current to stop a heart, so that's why we use GFIs etc.
So yes, that should be worded differently, but it's relatively minor in the scheme of things.
The main purpose for the ground wire is to get a high enough fault current to trip the breaker, because through the earth is basically never enough current to trip a breaker and stop a fault.
@@ke6gwf Many thanks for your reply it is much appreciated. Yes I understand that RCDs or what you call GFIs are used to trip when there is a current in excess or equal to a certain amount (typically in the UK 30mA) flowing to earth. When you say that ground and neutral circuits are only allowed to be bonded at a single point, otherwise the ground wire would have varying potential along its length since it would be a parallel current path. In the UK we sometimes use a certain type of earthing system called a TN-C-S which sometimes incorporates a PME which refers to Protective multiple earthing. This is where the combined earth/neutral conductor is connected to the physical ground in multiple places along the cable length. Would this be a case where there is multiple ground and neutral circuits and therefore it will have varying potential along its length? So from the point where the neutral and earth are combined they run all the way back to the transformer, then all the high resistance earth electrodes are each parallel paths back to the transformer? I hope this makes sense and apologies if you are unfamiliar with this type of earthing arrangement I'm not sure if where ever you're from uses this type and I'm assuming you're not from the UK when you referred to what we call an RCD a GFI. 🙂
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Amazing explanation!!
Thanks. Im sure I'll be back next year when im wondering about this again
Man my brain left half way through this. I’m a mess, but thank you for describing it to me
Great explanation
Thanks for sharing
I learned a lot from this video. Thank you. Question: In the sub panel, neutral and ground will not be bonded. In that case, where would the Fault current will go?
Please watch our sub panel video
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Great bit at the end to emphasize safety
Depending of what type of grounding system you have, the ground rod can actually be used for fault currents. In my area, we dont get ground from the services. Nor is neutral connected to our ground wires. We call that TT. What you describe looks more like TN.
I was just about to comment on this and thought surely someone already has,
I believe this video was geared towards the U.S. (We don't do TT installs here to my knowledge). We are strictly TN-C-S but we don't call it that. We call it "multigrounded neutral" (MGN) because we have to have our own terminology for everything, lol
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thank you very much, i learnt soo much from this video
Best vid on the topic out there.
Thanks!!!
The most important life saving practice is ALWAYS de-energize the circuit for the components you are working on. That’s the best way to not get electrocuted.
Exactamente; JAMÁS confundan la “TIERRA” con el “NEUTRAL!” 👍🏽
Smashing video. Can you do one on earth leakages caused by chillers, drivers, pumps, pfc, motors etc. we have this problem at work. We had 12amps at the MET. Found a loose PME rod. Rectified it and the earth leakage dropped to 9 amps . Turned the chillers off, the leakage went down to 7 amps. Checked the transformers star point and it's OK . Check all terminations. Still no answer
Sounds like an interesting problem. Can someone use a clamp meter to narrow down where it's coming from if you don't have the proper equipment.
Check all your neutral connections to as close back to the supplying transformer that you can. A bad / loose neutral will allow more current to flow through the ground to get back to the source. There should be no good reason to have ground leakage measured in full amps, milliamps, yes. Either a device is seriously damaged or, in your case and especially since it changed with varying the load, a bad neutral somewhere from the panel back to the supply. If you have to, have the power company check the connections on their end as well.
@@inothome I had, what appeared to be, a 'floating neutral'. Lights would flicker, dim, surge, all hours of the day and night. No correlation to any high-current devices. They did high-current tests between the pole and my panel, all checked out fine. I had the power company out 3 times. Each time they insisted it was something in the house. I tightened every screw in the panel myself, still happened. I tried shutting off different circuits, didn't matter. I had a licensed electrician come in and RE-check all my screws, connections, breakers--still happened. Paid to have them out twice. On the 4th time out, the poco tech said "I'll change out a few things at the transformer, see if that helps." Not sure what he changed, but it fixed it immediately. I had this, intermittently, for 3+ years. It took that long for the power company to actually fix it. They just kept denying it was their issue. Meanwhile, I spent a small fortune on tools, replacement breakers, electricians, checking every outlet box in the house... Infuriating. And can be really dangerous! So my advice: Check everything possible in your walls. But don't rule out a bad transformer or service problem.
This is why GFCI breakers and receptacles are so important. If you DO get across the hot side wiring the GFCI detects the ground current and trips the breaker almost instantly. GFCI breakers can be problematic in some situations.Exterior Christmas lights are good examples. If they get wet with rain or snow, they can trip GFCI breakers and GFCI outlets.
Frustrating, but safer.
GFI doesn’t “detect ground current,” as you said. It monitors the hot & neutral.
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0:00-0:09 That’s true for half a cycle (that current flows from the source to the load through the live wire, and from the load to the source through the neutral wire). In the other half cycle, it’s the opposite: current flows from the load to the source through the live wire, and from the source to the load through the neutral wire.
I suppose you didn’t say this because you usually use DC for explaining AC circuits. But I thought I’d clarify this because many other people say what you said without specifying that’s true only for half a cycle.
However even if the current flows in both directions, the neutral wire is referenced to ground, you only get a shock if you touch the hot wire.
@@FreeOfFantasy True. Though that’s not what I was talking about.
@@altuber99_athlete True enough about the actual current flow, But I agree with the way it's done in the video as it's less a less distracting way to illustrate the concept of grounding, esp. if the viewer is new to the subject and want's to know why the ground wire is important. I've seen films in the past that did the opposite. in a 1950's (?) film demonstrating simple circuits a battery, a switch and and several light bulbs were used for the visuals, but every time a circuit was demonstrated a 60Hz hum is heard. For the first few circuits, I could not figure out WHY a DC circuit would have a hum. It could not have been a simple indicator of the circuits working as a lit bulb (or bulbs....) would be enough for that. THEN they showed various way a SHORT circuit could occur, then I got it. They wanted to have a way to indicate that current flowed in a short no matter if no bulbs were lit. It was just to make it so a layman would understand.
@@jamesslick4790 Okay that's fine. Perhaps The Engineering Mindset should have clarified later in the video (after explaining ground), that current changes direction and thus for half a cycle it flows from the load to the source through the hot wire and from the source to the load through the neutral wire.
Every person watching this needs to understand that the service entrance ground bus is the ONLY place the bare ground and the white grounded conductor can touch. Anywhere else and you create multiple fault paths and a dangerous ground loop situation. One of the most common wiring errors.
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@3:00 Today's houses have the ground connection connected to the neutral before a differential circuit which senses the difference bw neutral and hot currents. Thus you cannot die, as soon as the difference is > 0 the circuit stops the flow of current in the house.
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I studied engineering in undergrad and I still don’t understand this stuff. I’ll rewatch this another time, but I’ll probably have to draw this stuff out myself to understand it.
If I may offer a bit of feedback: The video starts very abruptly with the ENTIRE THING shown. The whole image is animated, so the viewer has difficulty orienting themselves in it. You do not highlight what you're talking about with some bright frame or spotlight, and the animations keep switching without being synchronized with what you're talking about.
I'd recommend first establishing what's on the screen, with several sentences such as "On the left side, you see the electricity producer's transformer which converts [x] to [y]. From there, wires bring electricity inside someone's house or an office building. On the right is the electrical socket in the wall." etc.
Thanks for feedback. This video is literally just a snippet from our long video about the electrical system. Please watch that "Electrical panel basics" or "120 & 240V electricity explained" for full explanation
That System really remembers me on the fail-safety systems in my country. We use something called "die Nullung"
It's a modern version of the old Nullung ss it have some math stuff and more preparation
What it does: the system builds on breakers. Your electricity must be build, thst the breaker will be for sure cut down the wires.
Like: if you want to use a breaker LS-Typ B, then you need to get a currency of I×5
So if the breaker can hold 10A, then your system needs to get in worst cases everywherr 50A or more
Too that their are 2 or 3 other rolds, like grounding and so, that needs to work
The cables going to the ground rods are considered grounds. The wires used to connect metallic parts of the devices in the electrical system are bonding wires.
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lovely as usual but this time it's hard a little bit to understand because the distraction of eyes in so many items in pictures shown unlike some previous videos were so simple cuz few itmes in pictures and deeply concentrated ,, specially of non english speakers like me :)
Very well explained
thanx, a great & simple reminder of what it does when like me, its de las thing on your mind :)
The resistances of the ground wire at the outlet is no less then the resistance of the neutral wire. The current flowing thru a device and then back on the neutral doesn't trip the breaker because the device acts as a resistance item, aka resister, and doesn't allow the current to flow thru the device to over load the breaker. You can remove the neutral and connect the ground wire to the neutral connection and it will not trip because the wire has the same resistance as the neutral. In return you can connect the neutral wire to the case of a device and it will properly function as if it was a ground wire. In either situation if the hot wire touches either the ground wire or the neutral wire with no load connect in between, but a direct connection it will trip the breaker as a direct fault.
The question nobody seems to be able to answer is... why two separate wires? They're shorted together at one end, so isn't one of them redundant? Why not just, as you say, have the neutral wire connected to the case?
@@Bapuji42 Because the neutral wire carries current, the ground wire only does when there is a short. So if for example you was using a hand drill with a metal case, assume the neutral attached to the case, you can hold the case and with the drill off and be fire. Turn on the drill and now the case has current running through it and the your hand. if the resistance to ground is less through your body then through the neutral wire you will get shocked. Now if a ground wire is connected then you can use the drill and have short circuit protection without risk of getting shocked because the ground wire only carries current on a direct short which would trip the breaker instantly.
@@johnchase7667 That makes sense, thank you.
I thought of another reason. If something happened and there was a break in the neutral wire, everything attached to neutral "upstream" of the break would be at the same voltage as hot, since with no current flowing there's no voltage drop across any load.
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This channel helps so much. Thank you for the high quality videos!
Glad you like them!
This is just a bonded ground and neutral situation.
In europe we mostly use a terra terra setup, the ground is not bonded to the neutral. Or you get a separate ground and neutral wire delivered from the net.
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Makes you appreciate GFI's, don't it?
Is the central mystery "Electricity always tries to get back to it's source" ? This always seems to be the final simplex statement that concludes even the most edifying of descriptions of circuits / grounding.
Is there no way that equivalent power and application of electricity could be found by something equivalent to a giant over-charged balloon running to a different probably impossibly humongous under-charged balloon?
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very educative. Thank you
Thanks for making this Video
It's my pleasure
Great Video. I would have added Bonded and Unbonded panels into the mix. Since people like to add addition's to House's, Garage's, Shops, or Man Cave's. Or maybe I missed that video.
Thanks for the explanation, nice and simple to understand.
Can you do one for earthing in vehicles?
Excellent explanation.
Hi I'm watching you from Azerbaijan
Thanks Bro, This is what I am confused and for this such a long times about Ground cable for? Thanks also RUclips platform too.
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ruclips.net/video/Qi0ynSQw-wc/видео.html
Thankyou for this video but it would be best if you could give green clr to the ground line as it would be more clear + it’s what is used for grounds. Thanks
Ground is often bare metal in the US. Sometimes it has green insulation. EU does but it uses a completely different system.
That last situation would be protected by a GFCI in the circuit. If you haven't already, would be a good video too.
Thanks for the video!
🍺🍺🥃🍿🏌🏻♀️
Ah nice video. The 3 wire design in home electrical always confused me a bit, likely because I learned how to do electrical work on cars which use a 2 wire system and different terminology.
AC-DC (Not the band) 😉
Thank you so much for these videos! Is there any explanation as to why the ground has a lower resistance? Usually all the wires are copper. What's the difference. TYIA
The material is exactly the same, it just has a direct path back to the transformer
@@EngineeringMindset Thank you for the answer, if I can add to my question I would appreciate it. I didn't see in the video how the ground would trip the breaker. I don't see any physical connection from the ground to the breaker. Thank you for your time. Edit: Unless since this is AC there would be high current going back through the hot wire causing the trip.
Thank u very much I like yo channel so much hope u wd one day make for me videos of powerful amplifier coz I like to learn how to make them so much God bless you
Teşekkürler elektronikte ögrettiklerin için, Türkiyeden katılıyorum.Thank you for teaching electronics, I agree from Turkey.😀
Electricity is just cool.
Thank you for the useful information
This is really a good job. Thumbs up, which software do you make use of?