Electrical Grounding Explained | Basic Concepts

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⌚Timestamps:
00:00 - Intro
00:49 - Why do we a Ground?
01:23 - Earth Ground
02:07 - Graphical Symbol
02:32 - Common Ground
02:58 - 1) Typical example - electronic schematic
04:17 - 2) Typical example - Industrial schematic drawings
04:35 - Ground loops

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In this video, we’re going to discuss the commonly used, but often misunderstood term, Ground.

There are lots of different names for Ground…
There’s Earth, Earth Ground, Neutral, Common Ground, Analog Ground, Digital Ground, and Instrument Ground… just to name a few. And then you have terms like Ground Loops…

Quite often, Ground means different things to different people. For example, Ground to an electrician might mean something different than Ground to electronic engineers.

There are lots of reasons for grounding.
Proper grounding is a critical safety measure in all electrical systems and installations.

We ground the exposed part of electrical equipment so that internal wiring failures don’t raise the voltage potential of these exposed parts to dangerous levels.

Let’s look at some of the different perceptions of the ground.

It’s probably safe to say that Earth and Earth Ground are the same things.
Earth ground is the reference point in an electrical circuit that is a direct and physical connection to the earth. Earth Ground is the ground that you walk on.

Earth Ground is true zero volts. It is the true zero reference for any and every electricity discussion.

You don’t have to go far to see evidence of earth ground.
You might be able to spot a copper rod in the ground with a heavy wire attached to it.

This Earth Ground wire runs to your power panel and ultimately connects to all the Ground terminals of every receptacle in your house.

Notice that we’ve used an electrical symbol for Earth Ground.

The symbols used to indicate ground terminals are found in the International Electrotechnical Commission document IEC 60417 Graphical Symbols for Use on Equipment.
Symbol 5017 is the symbol for Earth Ground.

Every electrical circuit needs to be complete for the current to flow. In many applications, the common ground becomes the return path. For example, your car chassis is a common ground for the return current to the battery’s negative terminal.

Sometimes you’ll see the Earth Ground symbol used incorrectly on electronic schematics. The intention is to symbolize a Common Ground and it may not be connected to Earth Ground.

If ground points are not connected to Earth Ground but are connected to a Common Ground, it would be more appropriate to use the symbol IEC 60417 5020. This symbol suggests the points are connected to a frame or chassis terminal.

This brings up an interesting question…

Are all the components at the common ground potential connected at one point on the frame or chassis, or are they connected to the chassis at multiple locations?

Unfortunately, the schematic does not provide that answer. The schematic does not provide any clue as to physical connections. Industrial schematic drawings will indicate ground points and often provide more detail but physical connection points are still a mystery.

This brings us to a term called Ground Loops.

A Ground Loop is an unwanted electrical current path that can cause havoc in equipment or process control systems by introducing unwanted electrical noise.

These undesired Ground Loops are created when two supposedly connected points are not at the same electrical potential. That’s when Ohm’s Law takes over and creates an electrical current flow between two points.

Ground loops can be avoided if all devices are grounded together at one point. This type of grounded is referred to as Star Point grounding.

Unfortunately, in large industrial plants, multiple-point grounding is the reality, and the possibility of ground loops is high.

With so many connections referenced to the ground within a facility, the chances of needing more than one ground point are great.

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[realpars]

Want to Become an Industrial Automation Engineer or Advance Your Career?

[seeithappen]

I graduated in Electrotechnics and Electronics but they neaver teached this so clear during my school years. Thanks a lot for this useful information. I had ground loops problems in the metal box of a desktop computer that messed up the powersupply. Now I know what to do to solve it.

[zohaibali]

You are putting lot of work in making these easy to understand animations. Excellent job and thanks alot for sharing.

[sonnyfung]

I have been searching a video like this for my life. TONS OF THANKS.

[baconsledge]

Keep em coming, RealPars! Thanks for all your good content.

[jackzugna]

This is why in elettronic is better use "0V reference A/D", in the schematic you can highlight the connection with the chassis and the ground (if necessary), but also the connection between 0V-digital and 0V-analog.
If the target of your circuit are boats, cars or airplanes "ground" means the chassis of the veicle.

[owenduck]

Every man and his dog has a different take and definition on this. Frankly I don't think most people understand wtf is going on.

[s]

Thank you so much for this high quality content. Your responses to almost each and every comment speaks volumes. Subbed.

[JKTCGMV]

As soon as you mentioned that the ground symbol was the most misused I thought to myself “guilty!”
I’ve worked more with low voltage digital/analog circuits (mostly for classes at school, a little at work now) and we just use whatever symbol we like to denote a 0V point, without regard to whether it physically means chassis, Earth, or just a copper trace. At school this didn’t matter because every circuit we worked with was just a little bunch of wires and a battery, with no metal chassis or Earth connection to be confused with.

We almost exclusively used the most common “Earth Ground” symbol, but some professors would use “Common Ground” or “Chassis Ground” in their schematics.

[hubercats]

Thank you for sharing this helpful video. The only quibble I have with it is calling “planet Earth” the true 0 volt reference. More generally, voltage is the integral of the electric field between two points in space, and one of the points is 0 volts by definition (I.e., 0 volts does not necessarily refer to the planet Earth). Your video is, nonetheless, very helpful.

[johnfranco]

Superb presentation. Even people like me can understand about various grounding and importance of it.

[elmirelmir]

I was also asking myself what those people mean by saying "grounding". Now it is clear for me. Thank you very much!

[eugenepohjola]

Howdy. Great.
I usually say soil electrode and soil currents to discern from the fuzzy and blurry use of grounding and earthing.
Regards.

[albertwashingtonjr]

You should also note why it's important to declare what "standard" you use for the basis of your discussion. Still people around who think the NEC is a standard when it's not and it specifically states that. Also the symbology changes between standards i.e. IEC, IEEE, NFPA and JIC. JIC I believe is outdated, but if you declare that's what you're using, then you have to go by that standard. Love the video. Good explanations!

[vt]

Excellent video. Thanks for your enlightment!!

[RussLinzmeier]

I have an old physics textbook that describes the earth as a limitless energy sink that electrons can be poured into without it ever filling up .

[ardentdfender]

Damn excellent video explanation. Some Ground concepts I've never even quite heard of like the Analog and Digital Ground as well.

[sujithbalendra]

This. is. very. important. and. great. lesson. so. i. appreciate. your. this. video. lesson. so. Thank. you. very. much

[bvds]

Finally a near-complete discussion of ‘ground’. Excellent.

[sriyantra]

These techniques implemented in building (in1996) avionics test rig, at ADA B'lore.by (we) ex_HAL technicians under Sri V. Subbarao
All symbols (some I don't come across) are at one place to learn more. Thanks