Talk:Ground (electricity)
From Wikipedia, the free encyclopedia
I thought they used two wires for the telegraph first, then realized the ground could be used as a return path, and THEN started using only one wire, since it saved wire. - Omegatron 13:15, Jun 11, 2004 (UTC)
Contents |
[edit] green grounds
i just read that ground is color coded green because it was originally made of bare copper wires, which turn green over time. good point to add? - Omegatron 17:50, Jul 11, 2004 (UTC)
[edit] 1820 or 1830s which is it
neither the edit nor the reversion quoted sources
the edit mentioned tha kirchoffs cuircuit laws appeared in 1845 which is after both dates?!
the reversion just said "i think i have good reason to state 1820 but did not say what that good reason was" Plugwash 16:57, 1 Nov 2004 (UTC)
Heron justified his 1820 date for electromagnetic telegraphy. Theory was well behind practice. Ancheta Wis 17:14, 1 Nov 2004 (UTC).
- Thank you for accepting my date, Ancheta Wis. For your benefit, Plugwash, let me explain that my "reason" was this article on the Electromagnetic Telegraph, which I commend to you. It would be nice to find a corroborating source of information, so I shall keep looking. --Heron 20:20, 1 Nov 2004 (UTC)
[edit] Why....
Can somebody explain (in simpler words) why, if there is a fault in the circuit and someone touches it, the current runs to the ground and not to the person.... I've been looking all over the net and found nothing.
- It is a little tricky to explain
- the first thing to realise is earthing is not a cure all for problems with electrical installations just an important part.
- The other important thing to realise is that if you have a high resistance (the human body is fairly high resistnace :hundreds of ohms to about a megohm depending on factors like clothing type and skin wetness) and a low resistnace in paralell the bulk of current will flow through the low resistance.
- a popular misconception is that current naturally wants to flow "to ground". What it really "wants" to do is complete the cuircuit between the terminals of the supply transformer.
- At the supply transformer the neutral is connected to real earth.
- The earthing system of the house is also connected to the neutral of the supply transfomer (either directly or through the body of the earth.
- Protective devices (overcurrent protection is usuable for this with direct connection with indirect connection a rcd must be used) detect the current flow caused by the fault from a phase core to the earthing system and disconnect the power.
- furthermore to reduce shock risk further all metal that leaves the house into the ground is bonded together to keep the voltage between parts of it as low as possible.
- No doubts the electrons want to flow from phase-clamp (sin wave of 220v amplitude) of the generator to the zero-clamp. According to you, the current flows through somebody touched the phase just because (s)he stands at the ground, which is connected to the 0-clamp of the generator/transformer. You would not be in danger if the ground were a stub. The question is why do the electricity producers jeopartize us connecting the 0-wire to the ground? Why should we live on the conductor directly connected to the power source? --Javalenok 14:59, 29 January 2006 (UTC)
-
-
- Earth-neutral bonding is not negligence on the part of the electricity company. In fact, it is required by law for safety reasons. An explanation (sort of) can be found in our earthing system article. To summarise, the first insulation fault in an isolated (IT) system does not normally cause a dangerous condition, as you correctly said. However, once such a fault has occurred, the system stops being isolated and becomes unprotected, making it more dangerous than a proper TN system. One of the problems is that you don't know which wire has been grounded, so either wire could be hot, making the system unpredictable. --Heron 17:48, 29 January 2006 (UTC)
-
Benjamin Franklin was not killed during his 1752 kite experiment because he was insulated; he was not part of the conducting path. The current did not flow through him. One year later, George Richmann's lightning experiment took special care to ground himself; Richmann died instantly from his misapplication of grounding. Benjamin Franklin's lightning rod worked because it was not always part of an electrical circuit. It conducted to ground only when it was subject to a high-enough strike. The principle of insulation is the reason that electricians do not work from metal ladders; they use non-conducting ladders to insulate themselves from hazard.
I went to school with a girl who was unfortunate enough to be near a lightning strike. When someone asked her "What was it like?" she said: "I don't want to talk about it"; in other words, it was unspeakable.
We ground ourselves when working with electrostatic-sensitive devices, like memories (RAM), when the electrostatic charge that accumulates on us can zap the devices.
In some cities, inadequate inspection can fail to detect improperly grounded electrical power sources, which can be tied to more-or-less random locations; it is the responsibility of the installing electricians to adhere to the wiring code and to use proper ground locations. To do otherwise is to create an electrical hazard wherein unwary passers-by can accidentally touch a hot location, complete the circuit, and be electrocuted. Their unfortunate cases then become articles in the newspapers for us to tsk-tsk over. But there is actually a responsibility for the city and standards authorities to review the cases and investigate the causes of these silent, unmarked public hazards. If someone is electrocuted near you, stand aside. Otherwise you will join him. Let someone who knows what he/she is doing take over. Remember it only takes 100 microamperes to pass through your heart to kill you.
I remember one article where the passer-by once walked on a hot manhole plate on the sidewalk, killing her. Her father has since embarked on a campaign to mitigate these situations.
If you, the reader, still do not understand, please ask somewhere. Novices can start with electricity; then continue to Electrical connection. See also Isolation transformer and Electrical insulation, IEEE
[edit] "Uses" cleanup
Regarding the beginning of the first paragraph of the Uses subsection (summarizing power ground): Does this need to be edited? It looks like it got copied and pasted in from somewhere. I don't know nearly enough about the subject to trust myself to fix it without spewing inacurracies, though. Maybe someone who knows something about it can fix it? Michael Kelly 03:36, 23 March 2006 (UTC)
- That first paragraph has existed for several years, since at least this date October 2004; the conversational tone was not there as of '16:38, 20 August 2005 by Oliviosu', for example. Since the sentences have evolved over several years, the internal evidence is against a copy-paste. You are welcome to copyedit the conversational tone if that disturbs you. (Just don't ground yourself. Otherwise you could get electrocuted in the presence of dangerous current. That's why birds can sit on an electrical distribution wire; that's why Franklin survived his kite experiment. :=) --Ancheta Wis 18:53, 22 October 2006 (UTC)
- I personally would be comfortable with this edit to the first paragraph, from two years ago --19:24, 22 October 2006 (UTC)
- "NEC" refers to National Electrical Code (US) --19:28, 22 October 2006 (UTC)
- As a diff will show, "NEC (Article 250 ) You need to establish an effective ground-fault current path and the earth shall not be considered as an effective ground-fault current path. " was elided. I happen to think that useful advice. But it is now gone, as is the tag. Ancheta Wis
[edit] region?
There should be more info. about which regions prefer "earthing", "earthing system", as compared to "ground", "grounding", "grounded", "grounding system"?
This does seem extremely dependent on dialect, region, neighborhood.
Then there is "earthling".
hopiakuta ; [[ <nowiki> </nowiki> { [[%c2%a1]] [[%c2%bf]] [[ %7e%7e%7e%7e ]] } ;]] 22:28, 24 October 2006 (UTC)
[edit] Grounding/Earthing Grid
My English isn't good enough to write about what a grounding/earthing grid is but I suggest that an English speaking electrical engineer with experience in power substations write a section about it in this article.Renato Costa 14:52, 16 January 2007 (UTC)
[edit] Merge from ground conductor
A few of the nuggets from Ground conductor need to be moved here. And then that article needs to disappear. That article is not strong enough to stand on its own. If you have an objection, I would like to hear it. --Codeczero 01:50, 25 February 2007 (UTC)
- So what is wrong with an article about a type of conductor? Might there be an article about a voltage source? There is a lot of difference between a wire to ground and ground itself (the content of this article). If there is an article about the wire to ground, so much the better. You have to start somewhere on any article. The ground conductor on an electrical pylon is not the same as the concept and practice of grounding. --Ancheta Wis 02:22, 25 February 2007 (UTC)