If you are fed by three phase, how do you create an earth?

Dave

Dave wrote:
If you are fed by three phase, how do you create an earth?

Dave
I think you will find d that God did that already for you.;-)

The Natural Philosopher wrote:
Dave wrote:
If you are fed by three phase, how do you create an earth?

Dave
I think you will find d that God did that already for you.;-)

Groan :-)

Dave

"Dave" wrote in message
...
If you are fed by three phase, how do you create an earth?

Dave

Stake in the ground may well do!!

On Wed, 14 Apr 2010 21:21:11 +0100, Dave
wibbled:

If you are fed by three phase, how do you create an earth?

Dave

Generally, you are either supplied with one or you stick a rod (or equiv)
in the ground.

Or are you after a deeper understanding of neutral points in a 3 phase
system? eg If you *only* have 3 phase (no neutral), then you could put a
star wound transformer across the 3 phases which will create a neutral
point.

While you're at it, get a Scott or LeBlanc transformer and create
yourself a 2 phase (90 degree) system. Used to be popular in London -
that'll confuse the next bloke to PIR it!

--
Tim Watts

Managers, politicians and environmentalists: Nature's carbon buffer.

On Wed, 14 Apr 2010 21:21:11 +0100, Dave wrote:

If you are fed by three phase, how do you create an earth?

You don't, the distribution company connects the star point of their
transformer to earth. Even if you're fed at 11kv.

But I suspect that isn't what you wanted to know. Try being a bit more
precise with your question, then we can give an intelligent answer.



--
The Wanderer

Life is a catastrophic success.

The Wanderer wrote:
On Wed, 14 Apr 2010 21:21:11 +0100, Dave wrote:

If you are fed by three phase, how do you create an earth?

You don't, the distribution company connects the star point of their
transformer to earth. Even if you're fed at 11kv.

But I suspect that isn't what you wanted to know. Try being a bit more
precise with your question, then we can give an intelligent answer.

Many thanks for your answer, that explains it perfectly.

Dave

Tim Watts wrote:
On Wed, 14 Apr 2010 21:21:11 +0100, Dave
wibbled:

If you are fed by three phase, how do you create an earth?

Dave

Generally, you are either supplied with one or you stick a rod (or equiv)
in the ground.

Or are you after a deeper understanding of neutral points in a 3 phase
system? eg If you *only* have 3 phase (no neutral), then you could put a
star wound transformer across the 3 phases which will create a neutral
point.

While you're at it, get a Scott or LeBlanc transformer and create
yourself a 2 phase (90 degree) system. Used to be popular in London -
that'll confuse the next bloke to PIR it!

Thanks, it was just a thought that drifted through my mind a few days ago.

Dave

Fredxx wrote:
"Dave" wrote in message
...
If you are fed by three phase, how do you create an earth?

Dave

Stake in the ground may well do!!

I thought about that, but I know that electrickery is generated in 3
phases and wondered just how an neutral was made. It is quite clear now.

Many thanks to all who answered my pondering.

Dave

On Thu, 15 Apr 2010 18:59:04 +0100, Dave
wibbled:

Fredxx wrote:
"Dave" wrote in message
...
If you are fed by three phase, how do you create an earth?

Dave

Stake in the ground may well do!!

I thought about that, but I know that electrickery is generated in 3
phases and wondered just how an neutral was made. It is quite clear now.

Many thanks to all who answered my pondering.

Dave

In which case, these might be quite interesting for you

http://en.wikipedia.org/wiki/Three-phase_electric_power

http://en.wikipedia.org/wiki/Delta-wye_transformer

Oh - and that bit I was babbling about 2 phase systems:

http://en.wikipedia.org/wiki/Scott-T_transformer

Have fun!

cheers



--
Tim Watts

Managers, politicians and environmentalists: Nature's carbon buffer.

"Dave" wrote in message
...
Fredxx wrote:
"Dave" wrote in message
...
If you are fed by three phase, how do you create an earth?

Dave

Stake in the ground may well do!!

I thought about that, but I know that electrickery is generated in 3
phases and wondered just how an neutral was made. It is quite clear
now.

Many thanks to all who answered my pondering.

Dave

OK this is how it works in my installation: 11Kv overhead cable comes
onto the farm to a large pole mounted transformer on my land.
Transformer gives out 415v three phase, with the star point connected
to a large mat of copper wires buried under our goose paddock. Three
co-axial cables (aluminium core (phase) insulated from copper outer
sheath (neutral & earth) with overall insulation) all bundled
together go overhead to my barn where the three copper sheaths are
grouped and form my neutral and also my earth. The three aluminium
cores go to the company fuse and onwards to my distribution system..
The three phases and neutral continues up the road where at the next
pole one phase and earth/ neutral (still used as earth as only one
pole away from transformer) feeds my house. Subsequent poles trot up
the road feeding the neighbours about half a mile away. Their earth is
locally generated at the pole (another earth mat) due to the distance
from the transformer.

AWEM

"Dave" wrote in message
...
If you are fed by three phase, how do you create an earth?

Dave

Leccy board may well supply the earth depends on feed type .... or you may
need to supply your own via earth rod.

If this is initially a temporary supply then you will have to supply earth
rod.

Tim Watts wrote:
On Thu, 15 Apr 2010 18:59:04 +0100, Dave
wibbled:

Fredxx wrote:
"Dave" wrote in message
...
If you are fed by three phase, how do you create an earth?

Dave
Stake in the ground may well do!!
I thought about that, but I know that electrickery is generated in 3
phases and wondered just how an neutral was made. It is quite clear now.

Many thanks to all who answered my pondering.

Dave

In which case, these might be quite interesting for you

http://en.wikipedia.org/wiki/Three-phase_electric_power

http://en.wikipedia.org/wiki/Delta-wye_transformer

Oh - and that bit I was babbling about 2 phase systems:

http://en.wikipedia.org/wiki/Scott-T_transformer

Have fun!

Those links were very informative. many thanks for them :-)

Dave

In article ,
"Andrew Mawson" writes:

OK this is how it works in my installation: 11Kv overhead cable comes
onto the farm to a large pole mounted transformer on my land.
Transformer gives out 415v three phase, with the star point connected
to a large mat of copper wires buried under our goose paddock. Three
co-axial cables (aluminium core (phase) insulated from copper outer
sheath (neutral & earth) with overall insulation) all bundled
together go overhead to my barn where the three copper sheaths are
grouped and form my neutral and also my earth. The three aluminium
cores go to the company fuse and onwards to my distribution system..
The three phases and neutral continues up the road where at the next
pole one phase and earth/ neutral (still used as earth as only one
pole away from transformer) feeds my house. Subsequent poles trot up
the road feeding the neighbours about half a mile away. Their earth is
locally generated at the pole (another earth mat) due to the distance
from the transformer.

That's a Protective Multiple Earthing (PME) system, also called TN-C-S
if the consumer's installation uses the earth terminal supplied by the
supplier (which is optional).

The combined Protective Earth and Neutral (PEN) conductor connects all
the earth mats together - it's not that your neighbours have their own,
you all share them all.
The old Electricity Supply Regs (now superceded) required the PEN
conductor to be grounded no more than 60 metres from the consumers'
premises, and again periodically along the supply if consumers are
spaced apart significantly. (I haven't had cause to check the current
supply regs.) There was talk of changing the rules so that each
TN-C-S consumer would also require their own earth rod.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Mawson wrote:
"Dave" wrote in message
...
Fredxx wrote:
"Dave" wrote in message
...
If you are fed by three phase, how do you create an earth?

Dave
Stake in the ground may well do!!
I thought about that, but I know that electrickery is generated in 3
phases and wondered just how an neutral was made. It is quite clear
now.
Many thanks to all who answered my pondering.

Dave

OK this is how it works in my installation: 11Kv overhead cable comes
onto the farm to a large pole mounted transformer on my land.
Transformer gives out 415v three phase, with the star point connected
to a large mat of copper wires buried under our goose paddock. Three
co-axial cables (aluminium core (phase) insulated from copper outer
sheath (neutral & earth) with overall insulation) all bundled
together go overhead to my barn where the three copper sheaths are
grouped and form my neutral and also my earth. The three aluminium
cores go to the company fuse and onwards to my distribution system..
The three phases and neutral continues up the road where at the next
pole one phase and earth/ neutral (still used as earth as only one
pole away from transformer) feeds my house. Subsequent poles trot up
the road feeding the neighbours about half a mile away. Their earth is
locally generated at the pole (another earth mat) due to the distance
from the transformer.

That about sums up the answer to my question, which was triggered by how
do houses in the sticks get their power and earth.

Many thanks

Dave