Ground is MORE IMPORTANT than you think! EB#57

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 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.

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.

excellent video, bromigo. :elbowcough: Grounding is a deep subject and you're giving some very clear explanations

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.

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

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.

It's very important to ground our knowledge in the basics.

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.

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. 🙂 Grt

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.

Great Scott really gives some useful tips n information

my house was made in the 50s and has screw in fuses. looking at your 'fuse box' is like something from a spaceship.

This is the best video I have seen in YouTube about Ground. Thank you! I encourage you to make more videos about ground, in case there is anything interesting to add.

One of the most important questions that I wanted an answer of. Thank you for explaining it so well.

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.

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.

You did a great job of explaining and demonstrating how important proper grounding really is. Good work, keep it up!

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.

7:39 That's truly a PCB torture machine!