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neutral.....

06/14/2009 5:04 AM

hi friends,

i want to know clearly about neutral earthing grounding and how the wiring is done for a home

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Anonymous Poster
#1

Re: neutral.....

06/14/2009 8:41 AM

Earth grounding for residences are handled differently depending on your location. Best to contact your local building code authorities to get the specifics.

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#2

Re: neutral.....

06/14/2009 3:46 PM

Consult your local electrical wiring regulations and standards handbooks. Its all in there. Don't try and perform electrical work if you are not qualified to do so as the results can be rather fatal.

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#3

Re: neutral.....

06/14/2009 9:48 PM

PROFENG,

In United States, terrestrial applications electrical practices are governed by the National Electric Code.

Two colors are reserved to identify the function of conductors, Green for ground or earth, and white for Neutral these colors may not be used for any other purpose.

Philosophy is that green or white wire is likely at earth potential, and not hazardous, all other color wires are suspect and should be considered live.

In situations where white wire is used for live conductor such as switch loops with two wire type NMC (Romex) the white wire must be clearly identified on both ends by a color other than white or green. Colored tape is mostly used for this practice.

Good wiring practice is to use black wire for live supply to a switch, and red tape on the switched (White) return conductor.

For all but a few special circumstances (Some medical equipment for example) the Neutral conductor must be bonded to the ground conductor at the primary distribution panel ONLY! Bonding to a properly installed ground rod, and the structure's plumbing/ water supply must be done at this point also.

The neutral conductor White) must be "Continuous and uninterrupted", no switches or disconnects are allowed in the Neutral conductor.

The Neutral conductor (White), and the ground conductor (Green) must be separately connected to all appliances (Receptacles, lights, etc.)

Sub distribution panels must be supplied with the Neutral conductor isolated from the Ground conductor, single phase sub panels will require four conductors, L1, L2. Neutral, and ground, three phase sub panels with five conductors L1, L2, L3, Neutral and Ground. The Neutral conductor must be clearly identified either as a white wire, painted white, or wrapped with white tape, likewise the ground conductor must also be clearly identified green. Previously ground could be bare, no longer allowed, also previously clothes dryer and range neutral and ground could be connected together, also no longer allowed, must be connected with four conductor plug-socket.

Above information applies to residential structures, different but mostly similar rules apply to commercial and industrial applications.

Of interest may be that marine shipboard applications are governed by a different set of rules, (IEEE45), the entire electrical system must be isolated from the hull of the ship (Ground), and all power carrying conductors must be simultaneously opened, light switches must be 2 pole. There are exceptions to that rule also.

Philosophy of separating ground from neutral at all other locations except primary distribution panel is that in event of a short circuit (Neutral to line) the neutral voltage could rise above 50 volts, (Half the supply voltage) considering that the loop from the line connection at the distribution panel to the point of the short circuit back through the neutral to the primary distribution panel consists of same size wire, and same resistance.

Circuits of 50 volts and above are considered "High Energy" circuits, and must comply with different rules than low voltage circuits.

Have you noticed that landscape lighting is mostly 12 volt, and some restaurants use location lighting suspended from bare conductors?

Other rules apply, you need to consult National Electric Code, and local code regulations.

Regards CEKM

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Anonymous Poster
#4
In reply to #3

Re: neutral.....

06/14/2009 10:43 PM

hi CEKM,thank u very much for ur valuable information but i want the basics of neutral earthing and ground like current passes through it or not and what is what...

and if u can please give me some info about plc training softwares where i can download for free because i must work on it. thanks a lot again

Profeng.

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#5
In reply to #4

Re: neutral.....

06/15/2009 1:22 AM

CEKM, pretty much told you what the deal is.

If you really know what you mean by the word work, maybe you need to go walk out the door and find some building or home that has an electric service.

Neutral is one thing actually and grounding is another, by the way, though some people don't know the difference since they are used to everybody else doing everything for them.

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Commentator

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#18
In reply to #4

Re: neutral.....

06/15/2009 11:09 PM

profeng,

Current will pass through the neutral conductor when the current through the L1, and L2 conductors is imbalanced, the current through the neutral being the difference between that flowing through L1, L2, (And L3 in a polyphase circuit).

Ideally no current should pass through the ground conductor, but in reality likely some current does flow through the ground conductor due to insulation leakages, and of course large currents may flow through the ground conductor during ground fault (L to ground) short circuits.

In the U.S. we generally install ground fault circuit interrupter devices at point of use, or in distribution panels (For pool, Spa"s etc) specific circuits.

I have noticed that European practice is to install a GFCI main breaker, protects the whole house, however the whole house experiences a blackout when a minor ground fault is detected.

Any comments on why the European practice has been adopted?

Also of note ground fault circuit interrupters don't work on ships because the electrical network is not grounded (Not connected to the hull), some exceptions to this, and differences between U.S. built ships, and ships built in other countries.

Good source for information and training on PLC's is two day course by company called Trainco, sked can be found on net.

I took the PLC course, was very helpful.

I have been offered part time job instructing HVAC, Electrical maintenance, Hydraulics, and Pump repair.

Regards CEKM

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#22
In reply to #18

Re: neutral.....

06/16/2009 5:45 AM

I can only comment on a few things here, one being why is an ELCB is put in at the main switchboard. It is for two reasons:-

1) Its cheaper but covers the whole house. In Germany, as we have 3 phases, we have 3 ELCBs and only one phase will drop out. If designed correctly, some lighting/power should be available in each area on the other 2 phases...

In Germany (and the UK) even more sensitive versions will be installed for specific reasons at swimming pools, workshops etc...

2) On RN ships, we have the whole ship as an earth, connected via earth testing equipment to the 440VAC. No neutral or Neutral to ground connection. All Domestic supplies of 115VAC for lighting, some cooking and small motors etc are via Delta/Star transformers. As is 240VAC for other domestic reasons.....

If two phases (440VAC) are touching ground for some reason, there is a short. If the short is high resistance, only a small current will flow, if low resistance a high current will flow and blow fuses/drop a breaker......

This is kept to a minimum by keeping the various parts of the ships electrical system seperate....say 4 generators each supplying 1/4 of the ship.....many important units have ACO (automatic Change Over) equipment to stop the item dropping offline for more than say 2 seconds....steering motors for example.....

One of the jobs each week is to "Break down the board" and identify where items are touching ground and find and fix the equipment concerned.....

Its a never ending job on the 115VAC lighting circuits (each 115VAC transformer has on the LV side test equipment for earth chasing, in the relevant fuse box).

It happens very rarely on the 440VAC equipment, but must be checked at least weekly.....in fact, I remember only one 440VAC motor that got a short to earth.....it blew HRC fuses...we had to install a new motor till we got the other one repaired....

I hope this helps....

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#10
In reply to #3

Re: neutral.....

06/15/2009 8:01 AM

'good wiring practice is to use black wire for live supply to a switch and red tape on the switched (white) return conductor.'

In cable assemblies, such as a 2 conductor Romex, where used as a switch loop, the white conductor can only be used as the supply (when properly re-identified), not the return. See NEC200.7(C)(1)

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#15
In reply to #10

Re: neutral.....

06/15/2009 4:56 PM

Did you mean 200.7(C)(2)? -- JHF

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#23
In reply to #15

Re: neutral.....

06/16/2009 6:42 AM

Yes I did...thanks!

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#17
In reply to #10

Re: neutral.....

06/15/2009 10:48 PM

bmfckl,

Thanks for the correction.

For nearly fifty years I have done it the other way, Used black as live to a switch, and white identified as switched conductor with normally red tape unless other switch loops returned to a junction pullbox or trough.

When I graduated from Tech school, identification was not required, and I too often ran into neutral being switched. I adopted the practice to always identify the switch loop return long before it was mandated, and the habit has persisted, I reasoned that the black wire should always be assumed live, and the identified conductor may or not be live.

I try to keep up with changes in the code, but obviously I missed this one, I don't do much wiring except on my own house/s.

Thanks again for the information

CEKM

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#20
In reply to #17

Re: neutral.....

06/15/2009 11:31 PM

There is something almost opposite to the US over here (is it because we are at 180o apart ?)

Our colours are : Black = neutral, Green = Earth (or Ground) and Brownish red= Phase

Unless it is a 4 core cable, where it is RYB Black for the three phases and neutral.

This is one article on the coding

http://www.allaboutcircuits.com/vol_5/chpt_2/2.html

Does it not make things a bit confusing ? You take black as phase and we take it as neutral.

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#6

Re: neutral.....

06/15/2009 3:16 AM

Hello profeng,

Not to be insulting, but in most 'developed countries', and certainly in the UK and Europe, it is against the law to do any kind of electric installation, unless you are a trained engineer.

It does not sound as if you are an engineer, otherwise you would not ask the question!

I also do not know what country you come from, and electric regulation vary around the world.

Go to your local Library and you will find all the details you need to do what you want, and, or, to start learning about how to become an engineer. OK?

You could also get advice from an electrical engineer near you, do the work, and get them to check it before you use it?

bb

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#7
In reply to #6

Re: neutral.....

06/15/2009 3:34 AM

<...most 'developed countries', and certainly in the UK and Europe, it is against the law to do any kind of electric installation, unless you are a trained engineer....>

This is not the case in the UK.

All work in homes that falls under Part P of the UK's Building Regulations has to be certified by an approved tester upon completion. Other than that, there is nothing preventing the amateur, provided that individual is competent, from carrying out electrical installations that fall outside Part P, and from carrying out installations that will be tested afterwards to obtain Part P certification by others.

There is a great deal of electrical products available for the DIY home improver.

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#8
In reply to #7

Re: neutral.....

06/15/2009 4:21 AM

Hello PWSlack,

I got the first bit wrong. And what I meant to say is what you wrote.

But the high-lighted part of my post fits with what you say and he can work that way if he wants of course.

bb

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#9

Re: neutral.....

06/15/2009 5:44 AM

Hi mate, best advise is to get a electrician involved as you have no clue about earthing systems. If you dont understand the basics in your neighbourhood, dont touch it.

Find out the local regs and consult a local sparky.

This problem you have is very simple, dont touch, if you dont understand.

Please dont attempt any alterations.

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#11

Re: neutral.....

06/15/2009 8:19 AM

Pretty much all good replies so far. But to even try to give some advice we must know where you are.

Chas

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#12

Re: neutral.....

06/15/2009 8:36 AM

I hate to say this but if you had any decent thoughts at all on the subject you would have at least told us your location on this planet....

You should give us full infos as to "Why?" you are asking this question.....

Also, this subject has been covered in depth at least 10 times on CR4......a search on CR4 would have provided a massive amount of infos to read through.

Lastly, as others have pointed out, you are not well qualified for this work, so you should NOT take the screwdriver etc in your hands as you would be dangerous to yourself and others.....

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#13

Re: neutral.....

06/15/2009 9:54 AM

If I add the previous post (as a precursor to this post) then it looks like he is having a drawing in his hand and wants to check whether it is OK or not.

want to know clearly about neutral earthing grounding

Now at domesitc installation you don't ground(or earth) the neutral. Unless you want the Earth fault breaker to trip immediately (provided your drawing has one)

But just out of a bit of curiosity, your previous post says you are an ee graduate then you must know this aspect? At least these were taught in our good old times including the part that at home (or in anywhere else) do not connect load across the phase and the earth terminal?

You ground the earth wire only.

how the wiring is done for a home

Is supposed to be simple. Just check at home and that's all. Start from the incoming - meter-fuse-MCBs and rooms.

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#16
In reply to #13

Re: neutral.....

06/15/2009 10:32 PM

Thank you very much sb for ur valuable information.

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#14

Re: neutral.....

06/15/2009 12:04 PM

While the actual action of bonding of the nuetral to ground in an electrical panel is simple, usually done by means of a bonding screw, the rules and procedures for grounding the electrical service can get complicated and are subject to codes and standards set by the local utility. Therefore, you must contact your local power company to be sure that your installation will pass inspection; otherwise, you will probably end up re-doing some work before the power company will energize your service.

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#19

Re: neutral.....

06/15/2009 11:30 PM

Everybody else but me has been so nice, all I can say is Weird Science is a good song. Dumb as a rock the rules are, ground first, neutral second, then hots to make things work.

Dumb as a rock backwards and pulling it apart: hots then neutral, and then ground.

Apparently that's all I know and has kept me breathing.

Real electricians, unlike my sort, don't mess around with live power, like myself and my friends did.

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#21
In reply to #19

Re: neutral.....

06/16/2009 12:50 AM

Real electricians, unlike my sort, don't mess around with live power, like myself and my friends did.

Did your Avatar resulted from it ? I always wondered how did it happen

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Andy Germany (2); Anonymous Poster (4); babybear (2); bfmickl (2); capblanc (1); CEKM (3); EElectrician (1); jack of all trades (1); Joe Sparky (1); PWSlack (1); sb (3); Transcendian (2)

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