Ground is MORE IMPORTANT than you think! EB#57
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In this video we will be having a closer look at ground, earth, soil or however you want to call it. The stuff that is under our feet. In electronics you often hear ground when it comes to lots of different things. So I will do some experiment to show you why ground is super important and how it is getting used. Let's get started!
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0:00 Ground is Awesome, but why so many?
1:22 Intro
2:04 AC Cable with Ground Wire
5:50 Earth Ground (Electrostatic Problem)
9:19 Schematic/PCB Ground
10:17 Verdict - วิทยาศาสตร์และเทคโนโลยี
FINALLY, this is a topic that surprisingly little people have attempted to explain and in a simple and yet deep well put together way. It's honestly felt like a roadblock for electronics to me, google searches only get you so far. Thanks :)
I totally agree!
Same! I had some silly doubts which I did not dare to ask on Stackoverflow, but ChatGPT and now Greatscott is there for the rescue!
EXACTLY!!! I feel like nobody fucking understands what it means and so just rehash what others say. Hobby electronics people just use wires for everything, and I have never met an electrician who actually knows the physics intimately. They all just again rehash what they heard before without ever questioning it. All trades are like that tbh. Its disappointing. Its like the man version of beauty pseudoscience
I agree
@@melody3741
Exactly
I have asked about it but everyone just said the same stuff more or less I still don't know what a digital ground is really
I always make sure to include a few hundred grams of soil inside of every product I design, ensuring a reliable ground connection for the enclosure by shoving a wire into the soil and guaranteeing safety of the device. Proper grounding is very important!
Sorry, I had to.
Good practice. Everyone should do that.
Dude don't waste effort, You just have to lay the wire down & connect it with a glass of water.
@@greatscottlab 😂
make sure to have ground fault protection included in the product
meanwhile I am just using wireless grounding technology, way easier xD
my dad was working for a broadcasting company in germany. they had 3 metel towers for sending programs in medium wave frequency. they highest was about 188m in lenght. the stabilisation of the tower was build with steel wires to the ground. the wires had isolators at the end with a cable bridge to secure the towers to ground (earth) from electrostatic charging. the mass of metal in the towers made the electrostatic athmosphere effect very dangerous. my dad demonstrated this to me on a sunny day, he got safety clothes on and attached the ground cable. an ca. 10 cm long electric flash appeared. later he told me, that on rainy days there can be one flash about 30 cm and there can be ca. 10000v and more in it and a lot of current strenght.
In North America I often see “common” on schematics where it’s not really an earth ground like, for example, on circuit boards and vehicles. I have been involved in many situations where that distinction indeed matters, and the more experienced the electrician or electrical engineer, the more they seem to care about the distinction in the documentation.
My circuit board designs often have had a different net for common and earth ground so that the coupling between the two can be managed.
Thanks for the feedback. Interesting.
There are different symbols for real earthing and common point. Nobody knows them unless they have to work on something where it matters.
This is a topic that is a bit specialized, but there can be reasons to have separate "grounds" (a.k.a. signal returns) for analog and digital circuitry on a board. A metal housing might need to act as a shield against RF noise, and might need to have special care taken when connecting it to the signal returns. This is typically referred to as a chassis ground. These issues usually come under the heading of electromagnetic compatibility, and are discussed in those sorts of texts. As with many things, you can get by for quite a while without knowing too much about it.
@@prolarkaIt's used in particular when you have circuits that are mixed analog, digital and power electronics. Most of the time, each of those have their own specific common reference, and sometimes it's even not allowed in the electrical code to have a shared ground between the power (high voltage) and control (low voltage) parts of the circuit.
Common is called "Neutral" in Europe, as well as in UK, as well as in Australia, and other former British territories. 🇪🇺🇬🇧
excellent video, bromigo. Grounding is a deep subject and you're giving some very clear explanations
Thanks for the feedback :-) Happy to hear it.
90 percent of my electronic learning was learnt on this channel..
@@greatscottlabsay, how does ground work on a spaceship?
In some places it is up to 9 meters deep. 🤔
I'm an engineer who works in the grounding field; my favorite part of grounding is the research performed by Dalziel and Lee to determine the human body's withstand to various voltages and currents. Their research is the basis behind the decision making process for various overcurrent protective devices. Your video is great and does a good job summarizing the basics behind grounding
i'm going to copy/paste another reply (slightly extended here)i just posted under another thread in this video, without going into how many miliamps kill humans, because it's beside point, and because many places have no protection whatsoever:
neutral is always grounded on substation (step down transformer) side.
and that's exactly what killed 1000s of humans in the past.
ie prioritizing the protection of equipment (transformers, generators) vs. protection of humans.
because if you don't ground neutral, you can't kill a human, electricity has no will to go to ground when it has a better path (ie the other wire) , but this layout increases chances of lightning destroying equipment of the electric grid.
one more thing to mention: many places in the world (probably half the world) lack both rcd and grounding at customer's side, which means that
a) contact of live wire to metal housing won't trip the rcd or fuse
b) it's easy to end up dead (if you get a good ground connection, for example outside, for example construction site) even if you don't hold live in one hand and neutral in other.
why? because neutral is always grounded at substation and you'll get electrocuted via live and earth.
no need for 2nd wire if earth is your 2nd wire.
so, beware of all exposed metal that potentially carries charge. you don't know if protection is employed at that circuit.
it's good to have rcd and grounding, but this was not installed in many old buildings and houses, and it never will be installed. esp. in the "non western world".
It's very important to ground our knowledge in the basics.
One of the most important questions that I wanted an answer of. Thank you for explaining it so well.
A couple of clarifications, one short, one long.
1) My understanding is that in North America the use of the term Ground is synonymous with Earth. In Europe we tend to use Earth to refer to the Protective Earth (PE) connection, and sometimes a functional earth in RF systems, and use the term ground for all other functional 0V connections.
2) There can be many different earth/ground networks for many different reasons in a system, and these are often designated using different symbols in schematics and on connector markings. When using international electrical safety standards, such as ISO, IEC and EN standards, the symbol usually used by Great Scott consisting of three horizontal lines with decreasing length top to bottom, making a roughly triangular shape, is reserved for the Protective Earth (PE) connection only. Functional ground connections, such as the common 0V network in analogue and digital circuits, and which is not intended to carry fault current to protect users from electric shock, use different symbols. In my design schematics I use an open triangle for low current functional ground networks and a filled triangle for high current power ground connections. Some people use a thick horizontal line instead. But I only ever use the three horizontal line symbol for PE connections to conform to safety standards. I wouldn’t want my circuit to be misunderstood and for an electrician to wire a PE connection to a circuit that was not capable of handling fault currents and was not connected to Protective Earth by a sufficiently low impedance to ensure safety in the event of a fault.
I think your understanding is correct, though I would put it a different way: In the US (not sure about Canada, etc), instead of making a distinction between "earth" vs "ground" (which I personally think is needlessly confusing, really), the two concepts are formally identified as "protective ground" and "signal ground" instead. However, when the distinction is not necessary/important, both can (and often are) abbreviated as simply "ground", for convenience.
In German, it's usual to refer to the Protective Earth as "Erde" (the German word for earth) or also as "Erdung" (a connection to earth), while the English word "Ground" is used for the common zero voltage in a circuit or something.
(I'm not an electrician or anything, but that's how I as an electronics enthusiast know the words.)
Protected Earth is often specified with a circle while chasis groud uses slanted vertical lines. Open triangle is used for signal ground. The horizontal line triangle "ground" is too often used for the negative electrode of a battery or power supply.
@felix30471 I always use "Erde" for PE only, for all other GNDs, I use "Masse".
Living in the US, I've also heard these distinguished as "ground" and "earth ground".
Where I live in Portland Oregon the utility uses earth ground return for the high voltage distribution to residential neighborhoods. That means that on the top of the power pole there is only a single conductor coming from the utility that then feeds into a transformer. The other conductor that goes into the transformer makes its way down the pole and into the ground which completes the circuit with a similar conductor stuck into the ground back at the power distribution station. (Over a km away) I can only assume that back in the 1920s when they put the power in this neighborhood , this saved on copper. There are of course big warnings on this ground conductor that makes its way down the pole telling you not to cut it since if you did, that would then put that loose end attached to the transformer at some very high voltage.
It's pretty fascinating that they did it this way and I think it's somewhat unusual for inside a city. It also means if a single tree branch falls on the HV conductor nothing happens but if a tree falls on that's still attached to the ground, you get a short circuit. I have no idea if this ends up being more or less reliable in the long run.
On top of that, my house has earth ground with a rod driven into the ground. My earth grounding rod is probably only 25 m from the power pole which has the transformer on it with the earth ground return rod... It's all fascinating that it all just works and goes to show how amazing of a conductor the earth really is.
In the UK that would be called a TT sytem. terra terra
@@UberAlphaSirustrue, but in the classic domestic TT system there is still a neutral conductor
This sounds scary for many reasons
@@j--xe3ke remember that residential power in the US is split-phase, so the lack of a neutral on one side of the transformer is really no matter, since the other side is gavanically isolated anyway. The neutral, which is bonded to ground at the home, is the center tap of the 240V secondary of that pole transformer. The two 120V phases created this way are then referenced to that incoming neutral. The distribution neutral not being present means nothing in this situation.
Although, yeah. Having a broken ground end up exposing a 11 kV floating potential is not great.
4:41 Germany uses the TN-C grid system (Earth and Neutral connected together in distributionpanel) but also the TT electric grid system (Earth and Neutral separated).
If you have a TT electric grid system, and the Neutral wire comes in contact with the PE wire (chassis home device etc....) your RCD will also trip.
Here in Belgium we use the TT electric grid system, and depending on the load of the grid, and how far removed from the grid transformer, there can be a voltage between Neutral and PE between 0,5V up to 5V.
The exact amount of current that is available i'm not sure off, but it is way above 100mA because i have seen RCD's of 100mA trip when the Neutral touched the PE wire.
Because the current in the PE wire is not monitored by the electricity company, this voltage / current between Neutral and PE is in fact free electricity if you stay below the tripping point of the RCD. 🙂 Grtz
Nice to know, thx😀 you could plug a usb charger between N and PE😏
Ah, that explains why the RCD always tripped, when I cut wires with only the breaker disconnected. I always thought it was bad wiring or devices that created that neutral to ground voltage.
Well, you could try to get free energ... uhm... I mean electrical power without paying; but what's your plan how to use 500mW at best?
@@j--xe3ke , with 500mW you can run some small LED's, but in reality is less then 500mW. The 5V is somewhat maximum that is possible between Neutral and Earth. In reality here at home, i useally measure arround 1,5 to 1,8V (i'm not measuring this every day). With a RCD of 30mA installed for the entire house, that leave not much room, max 15a20mA of use, because there is always leakage present due the X and Y capacitors leakage in switching powersupplies through the entire house. So with 1,8V at 20mA it's only 35mW, enough for a couple small LED's. With a Joule thief, it can be scaled up a little for more LED's.
Here in India we follow TT earthing system. Without a RCCB, human safety is compromised in TT system. Practically the earth rod resistance cannot be maintained at o. Minimum possible is between 5 to 20 ohms in domestic service. Our house earth pit resistance value is around 12 ohms that too after watering!
Between earth and neutral terminals the voltage is around 2V.
You did a great job of explaining and demonstrating how important proper grounding really is. Good work, keep it up!
I am absolutely in awe at how nice and tidy modern German electrical panels are in general. Good use of plastic for touch surfaces and electrical boxes.
In Canada, we just love making everything out of stamped steel like we did 100 years ago and earth the ever-loving heck out of everything. Leaves a lot of safety in the hands of the installer, and much room for error.
This is the best video I have seen in TH-cam about Ground. Thank you! I encourage you to make more videos about ground, in case there is anything interesting to add.
7:39 That's truly a PCB torture machine!
Great Scott really gives some useful tips n information
Glad you think so!
Hi @GreatScott! Thank you for presenting that very important topic 🙋🏻♂️
Shoutout to your ABB electrical cabinet ❤
my house was made in the 50s and has screw in fuses. looking at your 'fuse box' is like something from a spaceship.
thank you so much for touching on this subject!
Thanks for clearing this out. I have heard other people complaining but it did. It really sink in completely before. Thanks again
8:40 this was the best explanation i’ve ever heard on grounding. Thanks
Finally one of my greatest mystery is solved! Thank you!
Well, Great Scott, that was a Great Tutorial. Much better then the lessons in school about 45 years ago.
Some more things I'd add:
- Static discharge can start fires, especially if there are any frisky substances in the air like petrol or natural gas.
- You sometimes see circuit/signal ground marked as "COM" for "common" to emphasize that it may not actually be ground.
- Another thing that is generally grounded is your plumbing, if your pipes are copper (or lead). Thus, most of the water that comes out of taps in your house is likely to be at ground potential.
Thank you for this excellent learning video!
Very nice and clear explanation. I was taught to have separate grounds for analog and digital parts of the same circuit and only tie them together at one point, where the common entered/left the board. But then, I'm a dinosaur. Thanks for sharing.
Thank u for expleaning this thing, It Always got me in the past.
Man I wish I could have a teacher like you, you are better than my entire ee department faculty.
Nice video! This was also one of the concepts I had difficulty grasping when I started out hobby electronics. Especially the difference between earth ground and chassis ground and voltage reference grounds.
Toasters generally don't have a protective ground in the US. This has always bothered me, since the electrically live heating elements are exposed.
6:18 Electricitiahh😌
PEN, nice. A sensible country. I've got 3x230 where I live. Every wire is live all the time. Except for PE, which is completely separate and virtual from all 3 phase wires. Truly fun stuff
After watching this video, I am glad, this guy is still alive 😅!
I have seen a triangle symbol used for common connections. The commonly-used ground symbol (3 decreasing length horizontal bars as in your video) is then reserved to show the connection to the earth.
This is just a preference thing of the designer, there's no standard usually for electronic schematics. When actual "ground" needs to be referenced in a circuit it's usually mentioned explicitly as PE (Protective Earth) in order to avoid confusion. There are national standards for electrical wiring diagrams however, such as the wiring of your house because those need to ensure proper electrical safety (both from shocking hazards and from electrical fires). So, whenever you see a circuit diagram with electronic components laid out on a PCB, the symbol for the ground there just denotes a common reference point. When you see electrical wiring diagrams, i.e. putting wires through walls etc. you will see an "N" (stands for "Neutral", the actual common point of all your household appliances) and a "PE" (stands for "Protective Earth", the thing that connects to the actual soil eventually) along with L1,2,3, etc (for "Line 1,2,3", i.e. each of the 3 phases coming from the utility pole).
@@InTimeTraveller The symbol shown in this video is actually the IEC symbol for protective earth (iec 60417-5017). So more like an ignorance thing, not a preference thing
@@WhiteBreamQuite so! My comment details the different networks called earth/ground and why it’s important to reserve the PE symbol for PE use.
@@BillySugger1965Yeah, but the IEC PE symbol specifically uses a circle around it to specify that it is protective earth.
In Canada we like to live dangerously. My metal toaster has a two wire ungrounded plug.
I do enjoy a "dont try this at home" episode 👍👍
Glad to hear it :-)
Yes, I'm sure the wife wouldn't be happy with finding burn marks on the toaster!! :-D
5:10 The RCCB or residual current circuit breaker is the equivalent to a GFCI or ground fault circuit interrupter in North America.
Beautiful video.
Finally, the explanation I was looking for, thanks!
Really great explanation! Thank you
I can see your good work all the way from Africa. 👏👏👏
Good topic my friend 👍👍🤝
Thank u Sir
Proof that Great Scott is becoming electroBOOM
Some old televisions had what was called a “live chassis” in which an isolation transformer was pretty imperative to use while performing service work on them to protect the technician from a lethal electrical shock.
It is worth noting that a respectable repair shop would perform a leakage test by measuring either the resistance of any exposed metallic pieces on the set to the neutral and live spade on the plug. Or, perform a voltage test of any exposed metallic piece to earth while the set was plugged in and on. . These types of tests were completed before the set was returned to the consumer.
It's not just old TVs and radios. Just about any modern power supply will have circuitry on the "hot" side. On many gadgets such as "smart" switches and other electronic control circuitry it's also common for all the internal circuitry to be live.
In terms of safety when troubleshooting you really just need to be careful not to touch the wrong thing. The safest way to do this is to (with the device unplugged) attach clip leads to your test points, then plug it in without touching anything.
Personally I've been doing work on an old TV with a true hot chassis (a huge hunk of metal directly connected to one side of the power line) and most of the time I would just plug it in so the chassis is connected to neutral, and I would also use a GFCI. I did get shocked a few times but it was shocks between locations on the chassis, something an isolation transformer cannot not help with.
Great one Scott! You should probably make some telsa coil drivers, ZVS circuits etc. High voltage circuits
Thanx for explaining this, it explains a lot about why losing earth is dangersous. Your electrical system in Germany is very similar to our Country's one.
Ground is important for way more things than electricity. It's one of my favorite things for standing on too.
thank you.
The apartment we rent is so old it doesn't have a Schutzleiter...yaaay. But well, in the current situation you have to take what you get.
Unexpected topic but everyone needs to know
Clear explanation super bro 👍👏👍
So nice of you
Another important reason why everything is bonded to ground: isolated systems are impossible at the scale we use it, e.g. the wiring from your transformer to your house but also to all neighbors in the street. Every device, power outlet and wire is galvanically connected to each other within this subsystem. With hundreds of meters of cable you always get a significant capacitive impedance to ground and thus there is always the chance for current (high enough to harm humans) to flow as soon as the circuit gets closed at another point. Ungrounded systems are used for example in operation rooms because the surgery has to continue even if one appliance has an electrical fault.
This video was very informative. I remember being very confused by grounding when I first started off in electronics and the differences between the schematic ground symbols and Earth ground. It took me a while to gain a better understanding of it. Your video is going to help clear it up quite a bit for electronics beginners.
The only video that I've come across that is even remotely similar was the video "EEVblog #279 - How NOT To Blow Up Your Oscilloscope!" by Dave Jones of the EEVblog channel. That was somewhat related because it addressed the importance of placing the ground properly for an oscilloscope probe and whether or not it is actually connected to Earth ground (and the consequences of not connecting it properly if that oscilloscope is actually connected to Earth ground).
Thank you for being willing to tackle such a difficult subject.
I remember that video! Watched it years ago before I bought my oscilloscope and went on a deep dive into grounding concepts.
Great video! Grounding has always confused me a bit, and it's great to learn this from someone who shares my electrical grid. I just didn't quite understand why the neutral is connected to Earth.
8:56 Hope this means a more in-depth video is in the works!
I was hoping this too!
The neutral is connected to earth for a "well-defined" reference. If you didn't ground any of the active conductors (IT-grid), the wires still form a capacitor between themselves and earth. You wouldn't "get rid" of any earth reference completely in an (extended) distribution grid, but get a "floating" voltage with respect to ground and touching any of the conductors could still lead to a current flowing to earth. Monitoring an IT-grid for insulation problems (to ground) and fault finding is much more difficult than it is in a TN- or TT-grid (where the neutral is grounded). A single (ground) fault in an IT-grid would basically only "degrade" it to a TN-grid, but not result in a short circuit or anything triggering overcurrent protection.
Imagine your neighbor tied L1 to earth somehow. In a TN- or TT-grid that would basically result in a short circuit and trip his circuit breaker (and RCD if there is any) and it would be obvious that something is wrong. But in an IT-grid the problem wouldn't be that obvious, but now you (and everyone supplied by the same transformer) now also have L1 at earth potential, and what you think is the "neutral" at 230 V (and L2 and L3 at 400 V) with respect to ground. Technically, everything should still work fine, but you can no longer assume that touching the neutral or a lighting fixture with the (single-pole) switch or circuit breaker turned off is "safe". (And you could draw current from the neutral by connecting devices between neutral and earth, maybe without sufficient overcurrent protection, depending on where the ground fault is located.)
Great video, ElectroScott 💥 ! 😉👍
Now i understand why i was often grounded by my parents when i was a child.
To protect those around me
You did an excellent job explaining it!
Thank you very much :-)
Very very good content, and i apreciate that you are doing experiments, is fun, and a lot of new thinghs to discover in them. You are a very good young teacher for many peoples, and your job is getting better with every new video!👍👍👍
That's crazy watching you.Draw something so neat and tidy with your left hand
I am right handed but have dyslexia So even my right hand is Terrible 😂😂
Very nice explanation 😁👏👏👏👍
Holy cow! I wanted somebody to do a video like this. You read my mind mah dude!
I had an electronic teacher in high school showing a somewhat lost girl how to ground an input by shoving the wire into the plant next to the us. He was great.
Very Interesting!
I'll just add that a RCD is great, but won't save you if you do something dumb like touching both live and neutral (and are insulated from ground, idk, carpet/ fur slippers). Then it won't trip as you will be just another "regular" load.
Thank you!
You're welcome!
Next part of The vídeo please teach us about the absorbing properties of our beloved ground from EMP's, and protection from undesired interferences, thats other plus when using a bottom layer ground at PCB design!!
Thank you for Explaining not my questions are cleared ❤
Great video! Nice explained ❤❤❤🇸🇪
"With such a long rod you usually get a pretty low resistance"
True, unless it scares her off.
more videos like this please. was great help understanding
More to come! ;-)
also want to add not only soil or the simple dirt, playdoah does pretty the same thing. I have done it before during one of the electronic projects with my group
Super Video mach weiter so!
nice explanation.
loved the video but amazed about your wood stove. so amazed that I couldnt write a comment and ask it to you. then paused and sccreenshot google lens helped. so it seems a masterflemme stove from a czech company. very effective and aesthethic design! hope they deliver to turkey! would love to see other devices in your home :D
In the US, the grounding electrode in the actual earth caps the voltage rise from induced currents due to EMP from lightning and also when large inductors (motors) are shut off. The moderate resistance between the building grounding electrode and the one at the transformer on the pole creates an always available path for when the induced current hits an open switch or loss of the combined neutral/ground on the triplex from the transformer that would result in a high voltage spike and possible arcing causing damage or fire. It began as a way to reduce arcing between the windings in large motors. In the past, an induced current on the "hot" side would pass through. motor winding or resistive light then be capped on the neutral. With electronics, we use surge protectors which pass voltage spikes to the bonded neutral rather than let the voltage arc through the transistors and such.
Very interesting video!
It is funny that kids don't get taught that wind can cause static build up........ This is also not very well known, but, in very dry climates like in my country where we are an arid country this is a major problem and also why ground mats and spikes tend to be buried and driven deeper into the ground as the ground dries out to a very deep depth here making the "earthing" of structures that much more involved. Well done.
Wish america's grid and electronics were more like that, clean and deterministic, maybe except the 230V
I like the idea of individual circuit breaks on each power and light circuit. This way he lights stay on when the toaster gets a shock to its left cheek. Might cost more but in a home at least the fridge still running and the lights stay on
nice video! it's almost midnight and this video is a feast for my tired eyes
Haha happy to hear that :-)
For those who do not know, actuall the cause of electrical shock from human touching Live wire (not talking about touching both L & N) is because the bonding of Earth and Neutral somewhere in Grid Transformer. Without any bonding to Earth from Neutral, it would not give shock, that is called Floating system and where L and N are both equally the same (both becomes Live but does not give shock if just one wire is touched). But because N and E are bonded, the Live will go through human body via Earth back to N. This is the precise explanation of electrical shock (or danger) that often people worry about.
6:40 for more info on earth as a conductor, look up SWER
Single Wire Earth Return.
Used in some remote areas in Australia and New Zealand, possibly others.
We get 220VAC from transformers which takes 11 - 13.8kV as input. Transformers are just 2 coils with a couple cm gap between HT and LT. If somehow a phase from HT gets into contact with LT which isn't properly earthed, Nothing will blow up, everything will work properly between phase and neutral but the moment anyone gets close enough to electrical fittings, 6.4KV will zap right through them.
Grounding also ensures every substation in an interconnected grid measures the same voltage in each phase wrt to earth, that's essential for fault finding.
Fantastic video, dude! Thanks a bunch for all the explanations!!! 😃
(Sorry I just commented today... I was traveling with my family. 😊)
Anyway, stay safe there with your family! 🖖😊
Can you make a video about different kinds of grounding? I don't really understand that topic.
For example how do we ground electronics in cars which are isolated from the ground? What's a floating ground?
I can put it on my to do list
@@greatscottlab Thx!
Agreed, I‘d be interested in particular in a video about digital and analogue grounds in PCB designs. The articles and videos I‘ve seen give me the impression that not everyone fully agrees about whether the distinction is really necessary, and if so how to implement ground separation on a PCB. IIRC The Great One has some practical experience building boards with digital and analogue components, and can probably demonstrate when things work well or poorly. Thanks @greatscottlab for another interesting video.
@greatscottlab Yes, please do! Also perhaps go into PEN, why neutral is connected to ground. This used to be a little strange when I was starting out, as it intuitively felt like that should kinda be a short or something.
@@slimhazardAnalog ground can be connected to a digital ground, but often needs a some additional isolation from digital ground as the noise generated from digital circuits is often noisy. Ground needs to be close to 0v in an analog signal, but digital systems often can take a range. 5V digital for example can have a "ground" signal that up to 2 volts and it'll be fine for the most part. If you are dealing with communication circuits it gets way more complicated as they are digital signals that act a lot like analog ones when operating at high speeds.
(ElectroBoom flashbacks)
True ;-)
I have some smart home switchable outlets with a 5v dc circuit inside. Depending on the L/N connection, the DC 0 reference is 230V.
Grounding of equipment is a highly complex issue in a wide range of experimental science and instrumentation, in particular at very low signal voltages and large installations. Ground loops can be the bane of an experimentalist and although one possible solution is to have floating equipment i.e disconnected from ground, this can have serious safety issues, since in many applications you have mixes of very high voltages in the 10's of kV range and signal voltages and currents in the 10-6V or pA ranges. I once had an experimental system which worked extremely well and achieved very high sensitivities without any ground noise issues and then I had to change a few components and power supplies and from one day to the next every thing went to pot and it took me a month to find the causes of the new ground loops being introduced by swapping out equipment.
In the UK we tend to call the green AC ground "earth" and DC Black negative "ground"
I'm probably too late and there's likely already a comment pointing this out, but: The PE on your mains connection is especially important in Germany because your plugs are never polarized. Since even the earthed ones can be inserted both ways, you can never assume which wire is neutral and which is live.
This is not true in North American wiring (for example), where there is supposed to be a guarantee of which one is neutral. Thus, for example, you can put your device's switch and fuse on just the live wire. In practice, though, that's not something that's good to rely on for safety since it's fairly common for them to be reversed by mistake.
I do not see your point. If the case gets energized the fuse will not blow, not even on inside the device. Device fuses are to limit damage to the device.
@@okaro6595If the case is grounded, it cannot be live and grounded at the same time--if a live wire touches the case _something_ will blow, whether it's the device's fuse or a breaker on the mains circuit.
@@okaro6595with respect to the comment I made about the switch--if you have an unpolarized mains plug and a switch only on one leg of it, then if the switch happens to be on the neutral leg, turning the switch off means the whole device is live (since it's connected to the live leg and there's no current flow to drop voltage).This is why many such devices have a double-pole switch to disconnect both legs. The same is true with the fuse.
My understanding with ELCB is as you say, measures current in Vs current out, but it also helps diagnose causes of issues.. so normal fuses and CB are protection for overload, so essentially too high current draw on a circuit or, there is a live touching neutral/Earth.. an ELCB measures or identifies leaks on the neutral and earth lines since even if the live is off, a neutral touching earth will still cause it to trip.. because there is still a potential between neutral and earth even when the live is disconnected from a circuit.. when you're fault finding, that kinda detail helps a lot..
Good stuff
In French, ground usually has two names. If the ground is the earth itself, we will call it earth, and if it’s not (like in electronics), then we call it the Mass, I guess as it acts kind of like a mass that attracts potentials, or something like that, referring to how it’s the 0V point
Danke!
Gerne :-)
Thanks a lot...
ElectroBoom will be proud of that spark and the breaker tripping
Could you please bring a COB designing video series / or one video regarding the COB parameters such as VIA , traces , how to choose planes etc☺
Difference is when talking 230VAC it's earth, when its digital electronics it's ground, which simply is 0V common reference. Interested to see your take on PEN though 👍
Also, it is usually good practice to flood any layer with ground.
And as soon as you connect your (digital electronics) phone to your computer via a usb cable it's ground is earthed. Or is the earth grounded then?
@@j--xe3ke Well its ground shouldn't be earth. You still want current to run in live and neutral then somehow transformed and isolated to produce a DC voltage supply.
@@bogmaerke I'm speaking of desktop PCs. Their metal case is grounded.
@@j--xe3ke The USB connection (female connector) of a PC is usually digital ground and not PE as the actual case might be. This is to shield the signals going into the cable (which usually also has a ground wire).
In my parents house in the 90's we had one water pipe that sometimes gave you a bit of a zap. It was an outside tap. So i wrapped copper around a half meter mild steel rod, drilled a hole in the concrete to expose soil, and drive that rod into the soil with the back end of an axe. Other end of the wire I wrapped around the copper water pipe for about 10cm, then welded it with lead and a torche with way to much flux. It worked.
Come to think of it now.... that was maybe not the correct fix. It is only hiding a bigger problem somewhere. I was 15 when i came up that that idea.
RCD = GFCI for American viewers. (And GFCI are typically only used in outlet plugs and not at panel breakers in American houses, and typically only in wet areas.)