[EricP]

Yesterday the local primary school had all their electrical equipment
junked. Copiers, computers, everything that was plugged in.
Sockets that were unloaded "sparked and smoked" .All the neons lights
went "very white and bright"

They are on triple phase mains. There were builders in but not doing
anything directly with the electrics.

The first informed comment was that at least 400 volts must have
passed through the place. Nothing can be found as a cause, it just
happened

Everybody denies liability including the suppliers. )

Anybody come across this sort of thing before?

[Chris J Dixon]

EricP wrote:

Yesterday the local primary school had all their electrical equipment
junked. Copiers, computers, everything that was plugged in.
Sockets that were unloaded "sparked and smoked" .All the neons lights
went "very white and bright"

They are on triple phase mains. There were builders in but not doing
anything directly with the electrics.

The first informed comment was that at least 400 volts must have
passed through the place. Nothing can be found as a cause, it just
happened

Everybody denies liability including the suppliers. )

Anybody come across this sort of thing before?

Once had a photocopier go up in smoke in the office, overnight.
Apparently some work was being done elsewhere which upset the
neutral point. Luckily it was seen before the place went up.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

[avocado]

I'm sure the suppliers main fuse would have blown on whichever phase
caused the problem. You say there were builders on site at the time -
sounds too much of a coincidence to me. Could it be that they shorted
two of the phases sending 415V down on of them?

[Tom Woods]

On 15 Feb 2007 10:28:54 -0800, "avocado"
wrote:

You say there were builders on site at the time -
sounds too much of a coincidence to me. Could it be that they shorted
two of the phases sending 415V down on of them?

yes. builders in schools are very good at denying all knowledge of
problems they have caused!
The ones round here are very good at breaking fibre links!

It is a shame that they didnt have a UPS on the main server in the
place. They generally log voltage fluctuations (and protect stuff from
them!).

[Colin Wilson]

Yesterday the local primary school had all their electrical equipment
junked. Copiers, computers, everything that was plugged in.
Sockets that were unloaded "sparked and smoked" .All the neons lights
went "very white and bright"

This sounds like a lost neutral, although i'm no expert on the full
effects of same.

Everybody denies liability including the suppliers. )

cough

If the schools' own spark has checked out the possibility of a lost
neutral on "their" side of the wiring, it may be a joint breaking down
under load on the supply side.

If you're in a Scottish Power area, can I suggest you call the emergency
number on 0845 272 2424 to get it investigated ASAP

Failing that, call whichever the local electricity company is, and get
them to come out in a hurry !!!

AFAIK you would have a valid claim if the fault was on the mains
network, but the common tale is to tell you to claim off your own
insurers.

[Bill]

In message , EricP
writes
Yesterday the local primary school had all their electrical equipment
junked. Copiers, computers, everything that was plugged in.
Sockets that were unloaded "sparked and smoked"
?????????

.All the neons lights
went "very white and bright"

They are on triple phase mains. There were builders in but not doing
anything directly with the electrics.

Builders will deny anything and everything, the VERY large dent that
appeared in my sink directly below where one had been using a club
hammer appeared miraculously one day. He never saw it happen though.

Any way as to your problem, although I'm no electrical expert, I've seen
similar twice but both times from 3 phase generators where the neutral
was missing.
Once at a golf tournament when the sparky lifted the neutral connection
with the genny running and powering a number of portacabins, loss of PCs
and copiers etc.
Secondly at a factory in Cambridge, Pye Telecom', we had only occupied
it for about a week when they decided to do the first generator check in
the evening and for whatever reason again the neutral wasn't connected
and everything was overvolted, it took days to test all the test gear
etc. before we could use it.

I'd grill the builders again, not literally of course, HSE might have
something to say about that.


Please do let us know if you find the cause.
--
Bill

[Andrew Gabriel]

In article ,
EricP writes:
Yesterday the local primary school had all their electrical equipment
junked. Copiers, computers, everything that was plugged in.
Sockets that were unloaded "sparked and smoked" .All the neons lights
went "very white and bright"

They are on triple phase mains. There were builders in but not doing
anything directly with the electrics.

The first informed comment was that at least 400 volts must have
passed through the place. Nothing can be found as a cause, it just
happened

Did it happen on every phase or just one (or two)?

If every phase was hit, I don't see how it could be anyone
other than the supplier's fault.

What about other premises nearby?

Anybody come across this sort of thing before?

Yes, got hit by a surge about 5 years ago. The only harm it did
me was to destroy the ethernet port on Sun Ultra 5. It belonged
to my employer and they claimed (I went for a plug-in ethernet
card, so I didn't have to lose the system to have the M/B
replaced). Lots of people got hit, and the supplier had to
switch the area feed due to a network fault, so there wasn't
really any question of denying it. I don't know what the voltage
surge went up to. It also caused all my X10 switches to take on
random settings, but they didn't suffer any long term damage.
It was in the middle of the night, so most things were switched
off (the Ultra 5 was on though).

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

[Harry Bloomfield]

avocado has brought this to us :
I'm sure the suppliers main fuse would have blown on whichever phase
caused the problem. You say there were builders on site at the time -
sounds too much of a coincidence to me. Could it be that they shorted
two of the phases sending 415V down on of them?

You cannot actually 'send' 415v down one cable or wire.

--

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

[Tim..]

"avocado" wrote in message
ups.com...
I'm sure the suppliers main fuse would have blown on whichever phase
caused the problem. You say there were builders on site at the time -
sounds too much of a coincidence to me. Could it be that they shorted
two of the phases sending 415V down on of them?


Shorting 2 phase wires together would create one-helluva-bang, not 400+v at
the other end.

Tim.

[John]

Chris J Dixon wrote:


Once had a photocopier go up in smoke in the office, overnight.
Apparently some work was being done elsewhere which upset the
neutral point. Luckily it was seen before the place went up.

Chris
Had a similar thing a few years ago, fax melted down. Electrician traced
it to a brass socket behind a boardroom sofa, vigorous movement of the
sofa had chafed the wires. The cause of the chafing was the office
cleaner and her boyfriend.......you couldn't make it up!

[w_tom]

On Feb 15, 11:31 am, EricP wrote:
The first informed comment was that at least 400 volts must have
passed through the place. Nothing can be found as a cause, it just
happened

230 volt electronic appliances are expected to withstand spikes of
up 1000 volts without damage. If the spike were longer, then that
maximum number would be lower and the event would be more obvious in
lighting.

A ballpark idea of how large a spike would be to do so much damage.