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Topic Title: stuck
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Created On: 24 September 2013 08:47 PM
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 24 September 2013 08:47 PM
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Avatar for OldSparky.
OldSparky

Posts: 592
Joined: 28 June 2011

hello peeps

i will try to keep this short and to the point

kitchen in a restaurant..

called out to investigate problem with extract system tripping out, couldnt find fault but did change the controller for the gas valve.

this was a month ago.

Called out today same problem with reported sparks coming from the fused spurs suppling the extract fans, also the bar ring had tripped, and a 3 phase oven on an other board.

again nothing found, on way home they rang to say lights were flickering and sparks coming from spurs again, and the bar ring had tripped..
they closed the restaurant

the only thing that happened the first time this happened western power were working in the street and knocked a few businesses out.

i am thinking a loose neutral, i would like your thoughts if possible

many thanks

Paul
 24 September 2013 08:54 PM
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Avatar for michaelbrett.
michaelbrett

Posts: 930
Joined: 28 December 2005

Sounds like a poor or no neutral causing increased supply volts.

Voltage measurements at the supply terminals of the CU or DB will confirm if the fault is still there?

Sounds like a lot of possible damage to equipment and accessories.

Regards

Mike
 24 September 2013 08:56 PM
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OMS

Posts: 19614
Joined: 23 March 2004

Almost certainly a neutral going open circuit - stick a voltmeter on it and get some load on - or do a L-N loop test at 25A - I'll bet it's wandering all over the shop - telling you that neural is about to go AWOL with all the usual fun and ganes that brings

Regards

OMS

-------------------------
Failure is always an option
 24 September 2013 09:21 PM
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Legh

Posts: 3482
Joined: 17 December 2004

lights were flickering and sparks coming from spurs again, and the bar ring had tripped..


I can understand that lights flickering and rfcs going off line suggests a loose neutral somewhere, but sparks coming out of the sfcu's ?

I assume that these were all checked for tight / clean connections?

Legh

-------------------------
Why do we need Vernier Calipers when we have container ships?

http://www.leghrichardson.co.uk

"Science has overcome time and space. Well, Harvey has overcome not only time and space - but any objections."
 24 September 2013 09:59 PM
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OldSparky

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Joined: 28 June 2011

Originally posted by: Legh

lights were flickering and sparks coming from spurs again, and the bar ring had tripped..




I can understand that lights flickering and rfcs going off line suggests a loose neutral somewhere, but sparks coming out of the sfcu's ?



I assume that these were all checked for tight / clean connections?



Legh



sparks out of the fuse carrier on the spur, the fan is only about 10amp

had it running for an hour before i left
 24 September 2013 09:59 PM
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Avatar for OldSparky.
OldSparky

Posts: 592
Joined: 28 June 2011

Originally posted by: OMS

Almost certainly a neutral going open circuit - stick a voltmeter on it and get some load on - or do a L-N loop test at 25A - I'll bet it's wandering all over the shop - telling you that neural is about to go AWOL with all the usual fun and ganes that brings



Regards




OMS



i am looking forward to tomorrow...
 24 September 2013 10:06 PM
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leckie

Posts: 1800
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Definitely an open or partially open neutral either at the incoming point or supply to the building. Same as OMS says, measure phase to neutral with a load applied. You will be getting between 230 - 400 volts fluctuating.
 24 September 2013 10:07 PM
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OldSparky

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Joined: 28 June 2011

thanks guys will let you know tomorrow night
 27 September 2013 08:14 PM
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Avatar for OldSparky.
OldSparky

Posts: 592
Joined: 28 June 2011

ok peeps

no loose neutral on the site,

only 2 things i can think it was,, a phase off or worse case a loose neutral but it must have been from the supply..

fitting a monitor for two weeks just in case it happens again
 27 September 2013 08:19 PM
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Avatar for OMS.
OMS

Posts: 19614
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As you said:

the only thing that happened the first time this happened western power were working in the street and knocked a few businesses out.


Almost certainly a supply side problem if everything looks OK your side

Regards

OMS

-------------------------
Failure is always an option
 29 September 2013 04:32 PM
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stateit

Posts: 2160
Joined: 15 April 2005

A bad crimp joint on overhead line caused this in a property near me. Infuriating to pin down.

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S George
http://www.sg-electrical.com
 30 September 2013 02:36 PM
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broadgage

Posts: 1282
Joined: 07 August 2007

Sparks coming from fused spur units suggests to me that a significant voltage existed between the CPC connected to the fused spur and some adjacent metal work at true earth. (and lack of effective bonding)

An open/partialy open PME conductor could do that, consider say 50 volts between the PME earth and true earth. Metal clad fused spur at 50 volts above true earth, and touching gas or water pipes or structural steel work that is at true earth.
Severe fire and electric shock risk.

An alternative explanation would a lack of an effective earth to the consumers installation.
Phase to earth fault raises voltage on CPC far above true earth, and the voltage difference between CPC and metalwork causes sparking, also very dangerous.
Statistics

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