A Facebook question about Earthing and Grounding

[_q12x_]

I find this question on Facebook:

And I give it my answer already and I will post my answer that I already made for it.
But I am curious what you guys will say first, without me influencing you with my answer.
I am an artist, I am not an electrician or electronist. My relation with electronics is in the hobby level. But I am an old hobbyist and not a beginner and I have some good knowledge from long time ago that I still remember and apply and guide even today.
I am curious what you will say, my good friend here, mister @marconi about this difference and if it is one?
Thank you.

 

[telectrix]

IMO, we call it earthing in the UK. you call it grounding in USA. that's the only difference., except for the fact that we only earth the neutral before the installation distribution board ( think you call that a panel).

 

[DPG]

Bonding means basically ensuring that a set of items is kept at the same potential. This will undoubtedly involve earthing, however it is a common point which is the key. It is no good connecting a water pipe to earth somewhere, and then some other metalwork to a separate earth rod which is not connected in anyway to the other earth.

That's trying to keep it in layman's terms.

 

[littlespark]

The way I always thought of it- rightly or wrongly- was that earthing was to do with the supply… the earth is the circuit path back to the power station or substation or whatever
Bonding was to make sure everything within touching distance was linked.. so you couldn’t touch a high potential and low potential at the same time. The clue is in the name “equipotential” bonding.

Ground, I took as something for DC circuits. Ie, on a vehicle.
The negative of the battery being attached to the chassis, and the return path of all loads was through the grounded chassis.

I’m sure some DC power supplies use “GND” instead of a negative symbol.

 

[Lucien Nunes]

As far as elecrical power wiring is concerned, it is mainly a language difference as mentioned above
British English: Earthed.
US English: Grounded.

For example, the terminal connected to the metal body of a fixture would be called the 'earth terminal' in British English but the 'ground terminal' in US English. The function is the same.

In electronics the usage of the terms is different. Earthing and grounding are sometimes used interchangeably, but in British English especially they can be used with different meanings:
Earthed: Connected to earth potential.
Grounded: Connected to the signal / power reference (common) potential, which might or might not be earthed.

For example, in British english I would speak of the green/yellow wire of the power cable to an audio mixer as 'earth' but the shield (screen) of an audio cable within it as 'ground.' This has changed over the years. An British electronic technician in the 1930s would likely have called the signal common 'earth' rather than ground.

In British English we sometimes use 'earth' or 'ground' to refer to the chassis of a motor vehicle, and speak of an 'earth connection' when in theory it is technically a neutral, i.e. a return conductor carrying load current that is near earth potential. This is an old-fashioned usage that has continued to the present day.

I’m sure some DC power supplies use “GND” instead of a negative symbol.

However the ground terminal is not always negative, e.g. many analogue electronics use both a positive and a negative supply relative to a common terminal, which might or might not be earthed but is often referred to as ground because it is the power and signal common connection. In this case the negative and the ground are two different things. A single supply with its negative grounded could use the terms 'positive' and 'ground' for the two wires.

There is no theoretical distinction between AC and DC as far as the difference between earth and ground is concerned. But in practical applications, typically if there are non-earthed DC supplies in a piece of equipment, the DC common might be called ground when only the AC side of the power supply is earthed.

BONDING is a whole different matter and the UK and US meanings are quite different. The OP didn't ask about it so I won't elaborate, to avoid confusion.

 

[DPG]

Flip! My brain saw that question as being the difference between earthing and bonding. Which to be fair is a more common question.

What Lucien said then!

I'll not mention positive earth cars from the 1960s because it might confuse things further!

 

[loz2754]

I'll not mention positive earth cars from the 1960s because it might confuse things further!

No. Please don't.

 

[_q12x_]

Thank you mister @Lucien Nunes , very interesting response.
I particularly like your phrasing: "...a return conductor carrying load current that is near earth potential..."
I never thought on the "earth" being a potential as you name it here. This is a new thing for me to keep in mind. I mean, everything is a potential after all, but for me earth is a surge surface and not usually a potential. But there is negative current as well, and that makes the "earth" a positive potential, so that's an interesitng point I didn't pay too much attention until you specified it. Again, overall interesting explanation and close to my explanation(which i didnt post it yet but I will). So, thank you.

 

[Lucien Nunes]

I'll not mention positive earth cars

I will. Positive-earth vehicles are covered by my reference to the use of 'earth' to mean 'neutral' in the context of vehicles. Positive neutral is perfectly reasonable; back in the day of 3-wire DC mains, half of all houses with a 2-wire service had a positive neutral (and a negative outer) and the others half had a negative neutral (and a positive outer).

The original question touches against many similar-but different questions; earthing vs. bonding, рабочий ноль (functional zero) vs. защитный ноль (protective zero), PME vs. TN-C-S, some involving language and electrical practices that have varied over time and place. Zero, middle wire, tomayto, tomarto, Potayto, potarto.

 

[pc1966]

I never thought on the "earth" being a potential as you name it here. This is a new thing for me to keep in mind. I mean, everything is a potential after all, but for me earth is a surge surface and not usually a potential.

The Earth is used to define zero voltage, as all voltages are potential differences, i.e. measured with respect to something else. The physical Earth is one conductive point that everyone can agree upon and has access to.

In electrical supply networks the neutral is "live" in the sense it is current carrying, but defined as neutral if it is connected to the true Earth somewhere. Where and how it is connected is an aspect the in turn defines different power supply arrangements and the related risks/advantages/methods of protection best employed.

This is why electricians ought to refer to "line" and not "live" for the conductor at high voltage w.r..t Earth ("hot" in USA parlance, though sometimes "phase" is used for this). But most UK folks use, at least sometimes, the common meaning of "live" to mean at significant potential w.r.t. Earth.

 

[_q12x_]

Yes I agree mister @pc1966, excellently put "the Earth is used to define zero voltage". For me, how I represent it in my mind, it is the element that every electron on this earth is surging, going into, flowing, descending, find a path to, directed into. The classical example of a lightning. Will always surge into earth. Literally. Also every other current at different potential.

 

[Lucien Nunes]

it is the element that every electron on this earth is surging, going into, flowing, descending, find a path to, directed into.

This is not an accurate way of looking at it. The only reason that current will flow from the utility supply hot wire to earth is that a return path has been made for it at the transformer station or pole, by connecting the neutral to an earthing tape or rods. If that connection were not made, there would be no tendency for the current to 'seek' the earth, nothing would flow apart from a little capacitive leakage. Earth has no magical current-sinking capabilities, in a sense it is just another conductor, one that goes everywhere and is available for everyone to use, and is used as an equipotential by every utility supply.

Lightning is a little different to utility current in that it is at a very high voltage with respect to earth. Because of that and the relatively large capacitance between earth and the 'supply' i.e. clouds, large amounts of charge are transferred when the dielectric of the air breaks down and discharges that capacitance. But again there is no magical current-sinking going on, it's just charging and discharging of capacitance. As much charge as is gained by the earth is lost again. Just the same as in the ignition system of a gas furnace but on a larger scale.

 

[_q12x_]

Mister @Lucien Nunes , excellent explanation. Thank you. I really like it.

 

[Megawatt]

Thank you mister @Lucien Nunes , very interesting response.
I particularly like your phrasing: "...a return conductor carrying load current that is near earth potential..."
I never thought on the "earth" being a potential as you name it here. This is a new thing for me to keep in mind. I mean, everything is a potential after all, but for me earth is a surge surface and not usually a potential. But there is negative current as well, and that makes the "earth" a positive potential, so that's an interesitng point I didn't pay too much attention until you specified it. Again, overall interesting explanation and close to my explanation(which i didnt post it yet but I will). So, thank you.

Bonding means basically ensuring that a set of items is kept at the same potential. This will undoubtedly involve earthing, however it is a common point which is the key. It is no good connecting a water pipe to earth somewhere, and then some other metalwork to a separate earth rod which is not connected in anyway to the other earth.

That's trying to keep it in layman's terms.

my friend I think you should have your answer as stated above by many brilliant people. I have nothing to add.

 

[_q12x_]

Thank you everyone for your very nice answers !!!
Yes, I left some time until all the answers gathered. Very interesting answers and I like them.
As I promised, here is how I see it. Keep in mind, that I am not an engineer in electronics or electrics. I am an (old) hobbyist who likes to learn new things about this world.
Of course there are more details that I fly over them, not mentioning them. Like the obvious US-UK terminology that everybody pointed it out. I just ignore it, purposely. And also I am not at the level of a well trained electrician, like you did explained better than me in some parts. Keep in mind, this is before your answers here.
So this is how I see it. It is part of my "general knowledge". And my experience.
Here is my original answer:

Thank you for reading.