Substation copper theft

Part timer

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Mar 25, 2011, 9:23:40 AM3/25/11

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I've read this piece on the website of a local paper:

http://www.thisishullandeastriding.co.uk/news/Undefined-Headline/article-3373086-detail/article.html
or http://tinyurl.com/68kao8g

Probably written by someone with a proverbial lack of knowledge, but
this bit puzzled me:

'All properties in the UK have electricity supplied at 240 volts.
However, without copper earthing, this can soar to 400 volts'.

Any ideas?

Dave Liquorice

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Mar 25, 2011, 10:41:31 AM3/25/11

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On Fri, 25 Mar 2011 06:23:40 -0700 (PDT), Part timer wrote:

> 'All properties in the UK have electricity supplied at 240 volts.
> However, without copper earthing, this can soar to 400 volts'.

415v between phases, 240 phase to neutral. The neutral is bonded to
real earth at the substation. Remove that bond and weird things can
happen depending on how well balanced the load is on the 3 phases. It
may also be influenced by how the loads are connected, delta or star.
That is about the extent of my 3 phase knowledge, someone will be
along in a while with chapter and verse.

--
Cheers
Dave.

Andy Wade

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Mar 25, 2011, 11:31:30 AM3/25/11

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On 25/03/2011 14:41, Dave Liquorice wrote:
> On Fri, 25 Mar 2011 06:23:40 -0700 (PDT), Part timer wrote:

> 415v between phases, 240 phase to neutral. The neutral is bonded to
> real earth at the substation. Remove that bond and weird things can

> happen [...]

It's neutral, not earthing, links that are being stolen, AFAIK. Each
outgoing circuit will have three line fuses and a solid neutral link,
the last being removable for complete isolation. Take away the neutral
bond on an unbalanced 3-ph 4-wire circuit and you unbalance the phase
voltages, some rising and some falling, wrt the now-floating neutral
conductor in the cable.

--
Andy

ARWadsworth

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Mar 25, 2011, 11:47:05 AM3/25/11

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Part timer <hhmn...@gmail.com> wrote:

> Any ideas?

Pikeys

--
Adam

RobertL

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Mar 25, 2011, 12:04:42 PM3/25/11

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In Norway there is no Neutral. Everyone gets three phases and the
sockets in each room uses two of them. there is 220V between the
phases. there's a fuse in each of the three.

I was told the reason was to reduce the maximum voltage relative to
earth.

if you blow one fuse then you end up having some rooms with their
sockets in series with the sockets in another room - turn on the
heater in one room and the TV comes on in the next room etc.

Robert

Harry Bloomfield

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Mar 25, 2011, 12:09:08 PM3/25/11

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Part timer explained :

All supplies are 415v 3 phase, which is 415v measured from any phase to
any other phase. The 240v is derived by connecting from any one of
those phases to a Neutral wire which is effectively the ground/ earth
connection at the sub-station. Basically, the idea is that all of the
240v supplies should be equally balanced loads on each phase, so that
no current flows down the neutral. Now if someone removes that bit of
bus-bar which connects it to ground and should the 240v supplies happen
to be badly balanced, then that 240v can rise upto the phase to phase
voltage of 415v. So instead of the 240v a domestic consumer might get
normally, they get 415v instead.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

GB

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Mar 25, 2011, 12:58:45 PM3/25/11

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Harry Bloomfield wrote:

> All supplies are 415v 3 phase, which is 415v measured from any phase
> to any other phase. The 240v is derived by connecting from any one of
> those phases to a Neutral wire which is effectively the ground/ earth
> connection at the sub-station. Basically, the idea is that all of the
> 240v supplies should be equally balanced loads on each phase, so that
> no current flows down the neutral. Now if someone removes that bit of
> bus-bar which connects it to ground and should the 240v supplies
> happen to be badly balanced, then that 240v can rise upto the phase
> to phase voltage of 415v. So instead of the 240v a domestic consumer
> might get normally, they get 415v instead.

Is there a reasonable chance that something would burn out and (hopefully)
trip the mains switch?

--
Murphy's ultimate law is that if something that could go wrong doesn't,
it turns out that it would have been better if it had gone wrong.

therustyone

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Mar 25, 2011, 12:59:14 PM3/25/11

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On Mar 25, 1:23 pm, Part timer <hhmnos...@gmail.com> wrote:
> I've read this piece on the website of a local paper:
>

> http://www.thisishullandeastriding.co.uk/news/Undefined-Headline/arti...
> orhttp://tinyurl.com/68kao8g

>
> Probably written by someone with a proverbial lack of knowledge, but
> this bit puzzled me:
>
> 'All properties in the UK have electricity supplied at 240 volts.
> However, without copper earthing, this can soar to 400 volts'.
>
> Any ideas?

It happened to a housing development I was in 25 years ago. Builders
dug through the UG cable neutral and left 400 v on some flats due to
unbalanced load. Midlands Electric, as it was then, replaced a large
number of TV's, kettles,fridges, heaters etc. etc. which went up in
smoke and flames. No one injured fortunately.

rusty.

Chris J Dixon

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Mar 25, 2011, 1:54:40 PM3/25/11

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GB wrote:

>Harry Bloomfield wrote:
>
>> All supplies are 415v 3 phase, which is 415v measured from any phase
>> to any other phase. The 240v is derived by connecting from any one of
>> those phases to a Neutral wire which is effectively the ground/ earth
>> connection at the sub-station. Basically, the idea is that all of the
>> 240v supplies should be equally balanced loads on each phase, so that
>> no current flows down the neutral. Now if someone removes that bit of
>> bus-bar which connects it to ground and should the 240v supplies
>> happen to be badly balanced, then that 240v can rise upto the phase
>> to phase voltage of 415v. So instead of the 240v a domestic consumer
>> might get normally, they get 415v instead.
>
>Is there a reasonable chance that something would burn out and (hopefully)
>trip the mains switch?

We had a copier burn out at work one night, due to some
ill-executed site electrical maintenance. Luckily the smoke was
spotted before it took the building with it.

Chris
--
Chris J Dixon Nottingham UK
ch...@cdixon.me.uk

Have dancing shoes, will ceilidh.

tony sayer

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Mar 25, 2011, 2:02:25 PM3/25/11

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In article <8v3qqi...@mid.individual.net>, Andy Wade <spambucket@maxw
ell.myzen.co.uk> scribeth thus

I've noticed that the copper lightning earth's at communication sites
are now being replaced with Ally and signs to the effect of "No Copper
on this site" are starting to appear..
--
Tony Sayer

Skipweasel

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Mar 25, 2011, 2:50:55 PM3/25/11

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In article <4d8cc9cb$0$2506$db0f...@news.zen.co.uk>,
NOTso...@microsoft.com says...

> Is there a reasonable chance that something would burn out and (hopefully)
> trip the mains switch?

Taking the Sky box first - so not all bad.

--
Skipweasel - never knowingly understood.

Robin

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Mar 25, 2011, 3:20:21 PM3/25/11

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>> Any ideas?
>
> Pikeys

Alpha mark to Adam.

(He would have merited 'Alpha +' for "pikeys, and our best hope is a
genetic engineering solution")
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com