grounding & earthing?

Hi,

you can understand it if you have some knowledge about electicity. Any alternating current produces alternating flux ( simmilar to a magnetic flux), this alternating emf produces a alternage voltage to any conducting body near to that alternating flux.

Thus our household items, TV, Refrigerator, Washing machine, etc which works on AC voltage can produce a voltage on their surface, which may be dangerous. If these items body connected to a earth, their surface voltage becomes zero. Which prevents accumulating surface voltage. Which we call as a earthing.

if a single phase AC voltage is produced, then you can find voltages at both the wire terminal , unlike DC source, there is no absolute ground or zero reference.

But if you produce 3 Phase or multiphase, and look at star winding of a AC generator,

the centre point of star winding will not have any current, i.e ,no voltage at centre point. This point we take as a neutral for single phase supply.

So far as I know, Ground can correspond to either of the definitions given by Sparky, depending on context and language (American English versus Commonwealth, for example). However, I believe he is correct that there is everywhere on this planet that the term "Earth" is used, its correct meaning is a at least a connection that is bonded a local Faraday cage, and in many jurisdictions Earth is also required to be bonded to a spike or multiple spikes that is/are driven into soil, rock etc.

That said, the terms have been used so sloppily that you can never even take the narrow correct usage of "Earth" for granted. So, unless the context makes the meaning unique - check. Lives can easily depend on this.

Here in the USA, and me being a young guy in my 60s, I have never heard the term "earthing".

We use "ground" for both definitions Sparky gave. Different countries, different definitions or way of talking about things.

Here, 110V-120V service is a HOT leg, a GROUND leg and a NEUTRAL leg. Look at the power pole and most, where there is a transformer providing service 110/220V for an example, will have a copper wire running from the GROUND lead down the pole and hooked to a GROUNDING ROD which is driven into the ground next to the pole.

The wires run from the transformer to the METER, through it into the FUSE PANEL/BREAKER BOX where they are hooked to the BUSS that accept the breakers. In a typical box will be the two 110V-120V BUSS bars the breakers snap onto. A double breaker (NOT two singles taped together!) across both the bars gives the 220V-240V for the stove/heater/air conditioner/dryer/well pump etc.

The two grounding bars in the box are connected to each other in the boxes here and there will be a ground wire running from these bars to another ground rod driven into the ground near the breaker box/fuse panel.

On a vehicle, it usually means the circuit that ends up hooked to the negative terminal on the battery. (some vehicles used the positive post as ground in the early 50s here. Strange, but that was the way Ford and maybe a couple others did it back then)

It doesn't matter if you are messing with a vehicle or the house wiring, if you short to ground, sparks will fly!

Ken

Don' forget that the neutral can either be bonded or not

By no means countering the explanations given by Sparkstation and the Guest, which are correct, Grounding and Earthing are one and the same. They could be used interchangeably, difference being only in the name.

Confusion seems to emanate from application of the words, as earthing is more pronounced in AC applications while grounding is more in DC applications.

Cheers,

ethobil

Nothing! The term used depends on were in the world you come from.

One has to be careful when using the terming grounding as there are different types of grounding conductors. The best place to start is with the National Electrical Code (NEC), NFPA Std. 70 definitions.

Ground is defined as the earth. Grounding is [the intentional] connecting to ground (earth) or to a conductive Body that extends the ground connection, so earthing may be seen as a form of grounding. The grounded conductor is a system or circuit conductor that is intentionally grounded such as a neutral conductor. A grounding conductor is a conductor used to connect equipment or the grounded circuit (mentioned above) of a wiring system to a grounding electrode or electrodes (grounding electrode system). Equipment grounding conductor (EGC) is the conductive path installed to connect normally non-current carrying metal parts of equipment together and to the system grounded conductor or to the grounding electrode conductor, or both. The EGC also performs a bonding function. A grounding electrode is a conducting object through which a direct connection to earth is established and may be defined as earthing; and the grounding electrode conductor is a conductor used to connect the system grounded conductor or the equipment to a grounding electrode or to a point on the grounding system electrode.

One should also be aware of the definition of bonding which is a connection used to establish electrical continuity and conductivity. A bonding jumper is used to ensure the required electrical conductivity between metal parts required to be electrically connected. And the main bonding jumper is the connection between the grounded circuit conductor and the equipment grounding conductor (EGC).

All of this relates to electrical safety.

I believe it's quite apparent he was looking for the "simple" difference between terms and not a National Electrical Code explanation interpretation of code language.

Else where in the world terms and codes do not correspond to the "National Electrical Code" as to means and methods, wording and terms.

Every language interprets terms differently.

I firmly believe in the "KISS" principle! If solves many simple and complex problems.

Hence the meaning for my tag! "They Know! What! Nah!"

Believe in chaos....always. It might just save us all!

For those of you from other lands and cultures, we arrogant Americans think we are alway correct at all cost.

KISS is an acronym for "Keep It simple Stupid."

You need to know the differences in: Equipment grounding conductor ----- Ground (green), and the Grounded conductor---- neutral (white or natural gray)

Hello noshorts

Your described earthing/grounding colour scheme may only apply in your local area.

In earlier days, Earth wires for apparatus were often quite different:

UK, Australia, New Zealand - Flexible cables: Green Earthing conductor

Germany: Red - A nasty trick - As I well remember a large Dental laboratory in New Zealand, back in the early 1960's, all connected by a Licensed Electrical Contractor, with the chassis of the equipment being connected to the Live phase connection, and he was unable to work out why the equipment would not work - fortunately no electrical shock occurred before the problem was remedied.

Later the UK, Australia, New Zealand Flexible cables: Green Earthing conductor gave way to a Green/Yellow striped conductor.

This was much better, as some men have inherited red/green colour blindness, but the striped conductor shows up easily, even for those unfortunates.

When connecting any electrical equipment, it behooves the installing electrical Contractor/Electrician to carefully check, even from so-called reputable suppliers, especially if the equipment is imported, and ensure safety by careful testing and Certification.

Local Codes and Regulations are made for a reason: To ensure standardised equipment for all local users.

Kind Regards....

Hello Sparky,

I concur completely. I have worked as a licensed electrician here in the states for over 20 years. Prior to becoming licensed, as well as after, I worked as a maintenance electrician. In doing so I have had experiences with German, French and Japenese equipment. They all have their subtle differences, especially the Europeann equipment and switching the neutral (in A.C.) and the ground (in D.C.) vs. switching the hots as we do here. Color codes also vary. The Japenese really like using Whites for hots, which drives us mad.

Over here the green w/ yellow stripe is to identify an isolated ground. Maybe as time progresses and everyone becomes more globally oriented we can get a universal standard. Unfortunately we ccan't even adopt a nationwide licensing structure over here. which leads to an encounter I had several years ago with a hog farmer. He had wired up a water trough heater to prevent the water from freezing in winter. The shop I was working for got called the next day because his hogs were dying. The heater was wired in without a ground and everytime a hog would drink it became a ground path.

" Over here the green w/ yellow stripe is to identify an isolated ground"
Even that code does not appear to be universal in the USA.

And, I am strongly of the opinion that an "isolated ground" is a ground that has the capability of becoming live under the most trivial fault conditions. Indeed, it can even become dangerously live if it supplies multiple non-faulty single-phase equipment having line filter capacitors to ground. It is certainly not a safety feature, and should only be used if it is essential to use equipment that is exceptionally sensitive to electrical interference. In that case the isolated ground equipment should be located so that the isolated grounds are very well spaced from any independent grounds.
Were it practical, I would have liked to see a requirement for all isolated grounds to be split into a live-facing section and a user-facing section, with sensitive RCD circuit breaker for the entire supply installed in the join between the two sections, and this in addition to standard RCDs in the live-facing section of each equipment. (Even if it is not always a direct safety feature, it would discourage equipment suppliers from unnecessarily specifying them)
Perhaps I'm paranoid - I put it down to experience (I'm a user, not an installer)

Isolated ground means that a circuit or panelboard derives it's ground seperately than the source feeding it.

You may be right - but in this jurisdiction that has become the standard version (PME having rightly lost the argument) - and isolated ground has come to mean a local ground that is separate from grounds used for other equipments - hence the specialised housings

I pretty much took Earthing to be the same as Grounding, but have enjoyed the discussion. Apparently there are some nuances. I am reminded of an instance when I was working Electric Department on a movie in the NC Mountains during a days long downpour. I noticed that the 1000 Amp Generator was not physically grounded to the Earth with a Spike, and asked the Genny Operator why not. He said it was internally Grounded, meaning to the Chassis. This "Ground" failed, resulting in some of what we call "bites", and a chassis to grounding spike in the earth solved the problem. Certainly my experiences on sets are a bit specialized. I do remember vaguely the term "earth ground", as in, "We need an Earth Ground". I seem to remember my Best Boy, who was a better electrician than myself, testing from neutral to ground, and seeing current. Often when working in the City, NYC, systems would ground to building plumbing, and even fire hydrants, but this practice was phased out as some plumbers were thereby shocked. On the house I am currently working, that is on a hill, surrounded by tall trees, above a field, and a pond, the house is grounded to a horizontally buried grid of grounding wire, due to the likelihood of lightning strikes. In cases where the ground is very hard it is good enough to bury the grounding spike horizontally. My point there is that there is more than one way to ground. Overall I feel an Earth Ground is superior, to a chassis ground, especially as far as portable generators are concerned.

I am not so sure that speaking about "grounding" vs "earthing" (the lexicon thing), given that they are essentially (ultimately) the same thing, is really the most succinct question to be asked....

The usage I most often see distinguishes (for reasons apart from "ground" definitions, other than of ground types) between system/network grounds as common, current-return-to-source (to anode or neutral, for example) conductors and earth ground as a common discharge conductor.

I could be off base but, seems to me that a common oversight that attends these "ground" vs "earth ground" uncertainties derives from seeing Earth as a ground which is non-conductive, when in fact it is a ground because it is conductive...a very massive conductor capable of dissipating (of conducting away, in all directions) all but the most improbable charge levels, but also a (generally) very poor conductor...such that the distance of current "travel" (especially AC) through Earth is very very limited in proportion as the level of current being "discharged" into it. Said another way, while it might be possible in principle to use Earth for current return in (say) a DC application, the current-source EMF requirement would be so high as to be impractical in the extreme...hence the use of common-conductor (metal-only) "ground" (you could say, "artificial earthing") for purposes of obtaining usable (and controllable) work...as opposed to reserving Earth (ground) for conduction and subsequent dissipation of extraneous charges (including injury-threatening charges) from which no useful work is practicably to be had.

Another, insightful line of discussion that bears relevance to the real ground or man-made ground question pertains to the "historical conversations," back in the gas light days, during which there was talk of using Earth (herself) as an essential conductor in "Edisonian" (i.e., DC) power distribution grids.

I hope you will find these musings--this seeing of the problem from a different (and perhaps more fundamental) angle--to be at least somewhat useful. (Also, reading these posts has me now thinking about another "Earth ground" question; but to keep things neat and tidy, I'll post that separately.)

About that other question...

Reading Sparkstation's description of proper Earth grounding methodologies brought to mind my own, somewhat dissipating experience trying to manually drive a steel rod ground electrode, to "great" depth (as I recall, about 6-8 feet, give or take), through clay soil and into the underlying hardpan horizon...because code requires it. Wiping brow repeatedly and asking myself, "Why such depth (and why even into bedrock)," at the time, the most logical answer seemed to be, merely to maximize surface interface between electrode and Earth.

Now, it also occurs to me that such a depth would place the pointed rod tip well below the biotic soil and well into abiotic horizons...probably everywhere an electrode might be sunk. The logical extension of this...is that too-shallow (120VAC) discharge into Earth ground could have adverse effect on living plant or animal life. So I wonder if anyone else has information about that.

Hello CowAnon

I well remember at a Telephone Call Box which was installed in a Hydro construction village at Otematata, South Island, New Zealand.

These Boxes were standard items, always painted bright red, and made entirely of wood, fitted with a spring-loaded wooden door and glass windows.

The coin-in-the-slot telephone had a metal casing, which was not to be Earthed.

There was a bulkhead type light fitted as standard, and the casing of that had to be Earthed.

The local ground conditions were "alluvial fill" = gravel, and after a couple of 7 foot long earth Rods were driven, we still could not get a proper "Earth test".

The Senior Electrical Engineer of the Construction area arrived, and insisted we obtain a proper "Earth Test".

What we did was to drive some 20 Earth Rods, all around the Telephone Call Box, connected all together with heavy copper cable, then back to the bulkhead light fitting case.

When the Senior Electrical Engineer arrived back, after some hours of our hard work, he laughed, saying the job was well done, because that light fitting, if it ever failed to the case, would never give a Call Box user any electrical shock.

That forest of driven rods is probably still buried underground, almost 50 years later.

Kind Regards....

Here in the states we tend to use hammer drills with a cup attachment to drive ground rods. I have had them hit a hard layer under ground and deflect resulting in the end exiting the earth some 10 or 12 vfeet away.

There is a compound that I have used in the past(I can't remember what exactly) that was poured directly around the rod and the vibration from driving it carried into the hole to improve the conductivity. This was at hospitals where we were installing the hook-up for a mobile CAT Scan unit.

A purely theoretical comment: if you are able to measure the ground resistance (rather than having a go/no-go tester), you could do the job with just two rather poorly grounded rods - so long as they are separated by the maximum of your twenty rods. Just measure the resistance between the two rods, the resistance between the casing and each rod separately, and the resistance between the casing and the two rods connected together, and calculate.

I doubt that's ever been much a part of the equation. However, I do recall using a generator from an old Ford with a hand crank to send a small electrical charge into the soil (Earth/ground) which drove out a rather plentiful supply of earthworms which were then used as bait for fishing.

the stripped green yellow for ground is terrific since I handled it with intuitive comprehension, along with noticing where it was in the box.

As the real estate folks say, "Location, location, location". Here in the States, we consider ourselves grounded, in Blighty they're earthed.

The only difference between grounding and earthing is which side of "the pond" you are looking from. If you are looking east over "the pond" we say "grounding". If you are looking west over "the pond" then the term is "earthing".

King's english --> earthing

American English --> grounding

Personally, I am East of the pond. I try to use Standard English, not always successfully. My accent is somewhat different from Received Pronunciation, and even further from that of their Royal Highnesses (whether dead or alive), so it is neither King's nor Queen's English.

In technical matters, I use "Earthed" to describe connections that specifically end up connected to conductors that are connected into the local strata, and "Grounded" for other reference connections. For international communications, I tend to refer to these as "Earth ground" and "local ground"; so far, neither has been misinterpreted, but that may be because of the narrowness of my audience.

In electrical work where ground is first to grab, and last to let go, when tying in live, or trying out, the knowledge of Ground Signification is very important. An international standard is recommended. Green and yellow allowing for the color blindness of some electricians appeals to me. Regardless of color coding a competent electrician ought to recognize what the wires do, by where they are. When I was tying in or tying out I came to regard Square D, or Cutler Hammer Boxes as better than the Seimens, which left little room to work, and seemed to have low grade aluminum bus bars. One of my friends had a bad arc burn from a corroded box. I have enjoyed this thread as an aside, and have learned that in some states and nations the ground wire is not necessarily coded, as I am used to. I myself love to have my ignorance altered. -Though I do believe I could work a box, for ground regardless of the color codes on the wires. There is a weird knot system that Film Techs used for working in the dark. I think there were no knots on the ground, and a knot on the neutral, and then 2 knots on the number one phase, and then 3 on the second, and 4 for Single phase, and 5 for three phase. I imagine that at end connections a bump code along with the color codes would be nice. of course if you have a flashlight color coding with tape is faster and works with interns more reliably.