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'[OT]: Four-wire electric distribution system'
2001\03\18@062441 by Attila Muhi

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Hi,

In Sweden we have a low-budget electric distribution system using only four wires, with a common wire for both neutral and protective ground. We split the neutral and protective ground in the fuse-box in our houses. That results in a lot of parasit current in the protective ground, especially when people, not necessarily in the same building, use powerful single-phase loads.

My question is:

Is Sweden the only country in Europe that don't use 5-wire transmission system, with separate ground and neutral wires ? I do work a lot with clearing those currents, especially for electrosensitive people, and I get very fed up with this ! Also, those automatic breakers (don't know the english word) that compare the current between the three phases and neutral, and triggers if there's a difference, keep trigging from those parasite currents !

Pooh !

Attila Muhi - SM4RAN

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2001\03\18@063517 by Alan B. Pearce

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The circuit breakers you talk of are known as "Earth Fault Current Breakers" or
"Earth Leakage Current Breakers" and seem to be becoming more widely used as
time goes by.

The mains distribution system you describe is what I know as "Multiple Earth
Neutral" and is how the mains is distributed in New Zealand. Each household has
a separate earth stake connected to a bus bar on the fuse board. The incoming
neutral wire is connected to an adjacent busbar. Only at the busbars is there a
connection between the two so an electrical inspector can disconnect them and
check for leakage currents. I suspect in a multi-storey building each flat would
have its own earth connection to a master earth point in the basement, but as
mains distribution was not my line of work, I do not know this for sure.

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2001\03\18@085202 by Bob Ammerman

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In the US common practice is to bring 3 conductors to the house/building:

2 phase conductors (180 degrees apart), each a nominal 117V from ground.

1 ground/neutral conductor.

As noted below for New Zealand, the protective ground and neutral are split
immediately at the entrance panel to the house or building, and from that
point on are maintained separately, including, in theory, but often not
practive any runs to outbuildings or subpanels.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)



{Original Message removed}

2001\03\18@091524 by Walter Banks

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Attila Muhi wrote:

> In Sweden we have a low-budget electric distribution system using only four wires, with a common wire for both neutral and protective ground.

I Saskatchewan where grew up the rural power distribution was a
single wire using the ground (the real one) as the return.

It worked quite well to supply power to widely distributed farms.

Each farm had a pole mounted transformer to provide a
center tapped 220v.  Normal outlets were 110V.

Walter Banks

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2001\03\18@092146 by Bob Ammerman

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>
> I Saskatchewan where grew up the rural power distribution was a
> single wire using the ground (the real one) as the return.
>
> It worked quite well to supply power to widely distributed farms.
>
> Each farm had a pole mounted transformer to provide a
> center tapped 220v.  Normal outlets were 110V.
>
> Walter Banks

Yep, and the electrons had to travel both ways, uphill, barefoot, through
the snow ;-)

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

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2001\03\18@100427 by Chris Carr

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Hi Attila

>In Sweden we have a low-budget electric distribution system using only four
>wires, with a common wire for both neutral and protective ground. We split
>the neutral and protective ground in the fuse-box in our houses. That
results >in a lot of parasit current in the protective ground, especially
when people, >not necessarily in the same building, use powerful
single-phase loads.

>My question is:

>Is Sweden the only country in Europe that don't use 5-wire transmission
>system, with separate ground and neutral wires ? I do work a lot with
>clearing those currents, especially for electrosensitive people, and I get
very >fed up with this ! Also, those automatic breakers (don't know the
english >word) that compare the current between the three phases and
neutral, and >triggers if there's a difference, keep trigging from those
parasite currents !

In Britain we always do things better :-)
You will find houses that are wired with no local earth, the Earth
connection being provided by the Electric Utility by earthing the Neutral at
the Substation.

Then you will find houses that are "properly" wired with a local earth
connection.

I have lived in houses wired to both standards and I can testify that the
PME system (no local earth) is Amateur Radio Hell. The only way round the
problem is to move to a house with a proper electrical system (that's what I
did) or provide a local earth yourself (if you are allowed by your local
regulations).

Before doing the latter, however, you should be aware that the safety of the
PME system requires that there be no local earth reference within the
building. In the event of a fault that results in a disconnection of the
Neutral Line between the Substation and the building, then all the electric
equipment in the building will rise to the line voltage (240volts in the
UK). This does not present a problem as the occupants of the building will
also be at 240 volts (Think of a bird sat an an overhead electric line).

However, if you have introduced a local earth and someone comes in contact
with both the local earth and electrical equipment whilst the fault
condition exists then as you say

>Pooh !

The person suffers from a condition known as "Terminated Living"  :-)

Regards

Chris

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2001\03\18@101242 by Oliver Broad

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I believe the UK is similar. I've read the designations for circuit types
but I'm not familiar with the notation. I understand that neutral and earth
are common up until point where the power enters a customer's premises. I'm
not aware of problems arising from this. A college near us was wired in
single core mineral insulated cable (sheath serving as neutral and earth)
and I understand this caused major problems with computer networks.


{Original Message removed}

2001\03\18@104022 by mike

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On Sun, 18 Mar 2001 11:34:36 -0000, you wrote:

>The circuit breakers you talk of are known as "Earth Fault Current Breakers" or
>"Earth Leakage Current Breakers" and seem to be becoming more widely used as
>time goes by.
Residual-Current Device (RCD) seems to be a much more common term
nowadays, at least in the UK.  presumably to reflect that current may
leak to places other than earth.! I think the Yanks tend to call them
Ground Fault Interruptors (GFIs) - or is that something different?

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2001\03\18@105100 by Nigel Goodwin

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In message <003301c0afbc$450a76c0$8b4601d5@dougal>, Chris Carr
<spam_OUTnyedTakeThisOuTspamBTINTERNET.COM> writes
>In Britain we always do things better :-)

We certainly have better mains plugs than most countries :-).

>You will find houses that are wired with no local earth, the Earth
>connection being provided by the Electric Utility by earthing the Neutral at
>the Substation.

I'm a TV service engineer, not an electrician, but I had some dealings
with this a couple of years ago. I fitted some storage heaters in my
attic (I got them for free!), and decided to feed them from 'Heatwise',
which is a method of cheaper electricity only supplied for a number of
hours a day, the exact times decided by the electricity company and
switched via broadcast radio signals. My meter is now an LCD one, with
FIVE!! different readings.

Anyway, in order to do this my wiring had to be checked by the
electricity company, they do this free (once!), but almost always fail
it first time, so they can charge the next time they come.

They failed my connection to the earth spike outside (amongst other
things!), as they said the thickness of the wire didn't comply with
current regulations, and I would either have to fit a thicker wire, or
pay them to provide a 'PME' earth. As I understand it they simply
connect your earth cable to their incoming neutral wire. I wasn't able
to fit a thicker cable (a couple of years ago I covered the earth spike
with 3-4 inches of concrete), so I  filled the form in for provision of
a PME earth (at about 40 pounds!).

When they came and re-tested, they passed everything - without fitting
(or charging for) a PME earth - it seemed the second guy wasn't as fussy
as the first!.

The basic distribution system in the UK is three phase, 230 volts per
phase, with a thin neutral. To spread the load to permit the use of a
thin neutral alternate houses are connected to different phases, only
industrial users would normally have all three phases connected into the
building. The neutral is grounded at the sub-station, and for a normal
local earth (using an earth spike) you can often measure 5-6 volts from
neutral to earth - and even light small lamps off it (at least before
earth leakage breakers!).
--

Nigel.

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2001\03\19@044728 by Kevin Blain

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I beg your pardon. Those breakers I described are overcurrent breakers. The
ones you refer to are

RCDs (Residual Current Devices), or
ELCBs (Earth Leakage Circuit Breakers), or
RCCBs (Residual Current Circuit Breakers)

Regards, Kevin

{Original Message removed}

2001\03\19@044936 by Kevin Blain

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Hey! We do this in the UK too!

Actually, it varies, depenting on where the system is, but the neutral is
bonded to earth at the local substation, and then in most cases, just phase
and neutral arrive at the subscribers premises, and the earth is taken from
the water pipes, etc.

In some cases, the phase and neutral come down a metal pipe, which will
therefore be passing through earth in order to get to the subscribers
premises.

If you have  problem with noisy earth, try to improve your bond to the
earth. Some long poles sunk into good soil, and a nice thick piece of cable
to the earth block ought to help.

Regards, Kevin

P.S.

automatic breakers == MCBs (miniature circuit breakers)


{Original Message removed}

2001\03\19@055939 by Russell McMahon

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> In the US common practice is to bring 3 conductors to the house/building:
>
> 2 phase conductors (180 degrees apart), each a nominal 117V from ground.
>
> 1 ground/neutral conductor.
>
> As noted below for New Zealand, the protective ground and neutral are
split
> immediately at the entrance panel to the house or building, and from that
> point on are maintained separately, including, in theory, but often not
> practive any runs to outbuildings or subpanels.

One had better do it in practice in NZ as well or risk the wrath of
authroity. All commercially installed wiring will invariably have separate
earth and neutral runs throughout the property.



       Russell McMahon.

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2001\03\19@062510 by Bob Ammerman

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----- Original Message -----
From: Russell McMahon <apptechspamKILLspamCLEAR.NET.NZ>
To: <.....PICLISTKILLspamspam.....MITVMA.MIT.EDU>
Sent: Monday, March 19, 2001 2:39 AM
Subject: Re: [OT]: Four-wire electric distribution system


> > In the US common practice is to bring 3 conductors to the
house/building:
> >
> > 2 phase conductors (180 degrees apart), each a nominal 117V from ground.
> >
> > 1 ground/neutral conductor.
> >
> > As noted below for New Zealand, the protective ground and neutral are
> split
> > immediately at the entrance panel to the house or building, and from
that
> > point on are maintained separately, including, in theory, but often not
> > practive any runs to outbuildings or subpanels.
>
> One had better do it in practice in NZ as well or risk the wrath of
> authroity. All commercially installed wiring will invariably have separate
> earth and neutral runs throughout the property.

I live 'in town', so when I ran a 100A 240V underground feeder to my 'barn',
I had to maintain separate neutral and protective ground, but I was allowed
to use #6 CU for the protective ground (much too small for a 100A load!) on
the theory that any significant current in the protective ground due to a
fault should be short term.

In addition, I had to include a ground rod (driven 8ft into the ground) at
the outbuilding connected to the protective ground.

On the other hand, next month I am installing an overhead 100A feeder to run
from one building to another at a campground where I volunteer , and the
inspector has explicitly said that it is ok to run only a single conductor,
rather than separate protective ground and neutral. This is, of course, in
violation of the National Electric Code, but very common in rural areas.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

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2001\03\19@114644 by Harold M Hallikainen
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On Mon, 19 Mar 2001 06:18:14 -0500 Bob Ammerman <EraseMERAMMERMANspam_OUTspamTakeThisOuTPRODIGY.NET>
writes:
> On the other hand, next month I am installing an overhead 100A
> feeder to run
> from one building to another at a campground where I volunteer , and
> the
> inspector has explicitly said that it is ok to run only a single
> conductor,
> rather than separate protective ground and neutral. This is, of
> course, in
> violation of the National Electric Code, but very common in rural
> areas.
>

       So, the return current is passed through the "local earth" (such as a
water pipe)? And if there's a 1 ohm resistance to ground, all the water
faucets are 100V above ground?

Harold


FCC Rules Online at http://hallikainen.com/FccRules
Lighting control for theatre and television at http://www.dovesystems.com

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2001\03\19@120224 by Bob Ammerman

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----- Original Message -----
From: Harold M Hallikainen <haroldhallikainenspamspam_OUTJUNO.COM>
To: <@spam@PICLISTKILLspamspamMITVMA.MIT.EDU>
Sent: Monday, March 19, 2001 11:27 AM
Subject: Re: [OT]: Four-wire electric distribution system


{Quote hidden}

as a
> water pipe)? And if there's a 1 ohm resistance to ground, all the water
> faucets are 100V above ground?

No, unless the neutral conductor is grossly undersized. At most you would
have about a 10V drop across the neutral.

There _IS_ a neutral conductor, sized the same as the phase conductors, but
there isn't a _separate_ protective ground conductor as required by code.

Here is a summary:

From the pole (power company property) to the house/building:

2 phase conductors sized for entire load
1 neutral/ground conductor typically same size as phase conductor.

In the 'service entrance panel' of the building:

The incoming neutral/ground conductor connects to two separate busbars in
the panel, one of which is treated as the protective ground and the other as
the neutral. In this box, and only in this box (according to the code) the
two are connected together. In addition, separate earth ground conductors
are run from the service entrance panel to the local water pipe, gas pipe
and a ground rod.

All other connections are then supposed to be four wire:

2 phase conductors (often black and red)
1 insulated neutral (usually white)
1 uninsulated protective ground

In rural areas the uninsulated protective ground is often omitted on runs to
outbuildings and then the 'service entrance panel' in the outbuilding is set
up the same as the 'service entrance panel' of the main building (two
separate busbars - tied together, plus earth grounds to water pipes, ground
rod, etc.)

In urban/suburban areas you generally have to run a four wire to the
outbuilding. In this case the two busbars in the service entrance panel are
not bonded together, although the protective ground is connected to water
pipe, ground rod, etc.

Even in urban/suburban areas many old (grandfathered) installations use a
simpe two wire (hot and neutral) or three wire (two phased and neutral)
overhead connection to garages and the like. Again, there should be a
'protective ground' established at the garage.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

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2001\03\19@141343 by Peter L. Peres

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>I Saskatchewan where grew up the rural power distribution was a
>single wire using the ground (the real one) as the return.
>
>It worked quite well to supply power to widely distributed farms.
>
>Each farm had a pole mounted transformer to provide a
>center tapped 220v.  Normal outlets were 110V.
>
>Walter Banks

I'll take your word for this but I suspect very high line voltage and a
step current problem near the pole with the transformer on dry days (are
there any dry days in Saskatchewan ?). Also any polar light and serious
magnetic disturbance would do terrible things to such a system imho. True
?

Peter

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2001\03\19@194441 by John Mullan

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-----Original Message-----
From: pic microcontroller discussion list
[RemoveMEPICLISTTakeThisOuTspamMITVMA.MIT.EDU]On Behalf Of Chris Carr
Sent: Sunday, March 18, 2001 10:01 AM
To: spamBeGonePICLISTspamBeGonespamMITVMA.MIT.EDU
Subject: Re: [OT]: Four-wire electric distribution system


Hi Attila

......

However, if you have introduced a local earth and someone comes in contact
with both the local earth and electrical equipment whilst the fault
condition exists then as you say

>Pooh !

The person suffers from a condition known as "Terminated Living"  :-)

Regards

Chris

Could put a damper on the poor guy's day......

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2001\03\20@013704 by Kevin Maciunas

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On 19 Mar 2001 20:50:08 +0300, Peter L. Peres wrote:
> >I Saskatchewan where grew up the rural power distribution was a
> >single wire using the ground (the real one) as the return.
> >
> >It worked quite well to supply power to widely distributed farms.
> >
> >Each farm had a pole mounted transformer to provide a
> >center tapped 220v.  Normal outlets were 110V.
> >
> >Walter Banks
>
> I'll take your word for this but I suspect very high line voltage and a
> step current problem near the pole with the transformer on dry days (are
> there any dry days in Saskatchewan ?). Also any polar light and serious
> magnetic disturbance would do terrible things to such a system imho. True
> ?
>



Here in Australia we run 415V 3phase power, 240V to neutral.

In the more-rural less-urban parts of the country (that's probably about
99.5% of the state of South Australia :-) )
power is supplied via a SWER (Single Wire Earth Return) feed.  Cheap -
one catenary.  It runs at either 11kV or 33kV.  Those whom I know who
have SWER lines have zero problems EXCEPT the power company provides the
step down transformer and they skimp a bit so the archetypal farmer arc
welding the tractor in the shed whilst spouse is cooking dinner causes
the kid's computer to reboot.  Come to think of it, that could be a
feature!

Apropos the dryness etc - no.  The earth is a fine conductor.
"Watering" the earth stake on the transformer does nothing for you.
Can't speak about the aurora - we're too far north :-)

/Kevin

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Dept. of Computer Science      Ph : +61 8 8303 5845
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