[TCUG] Re: Installation Earthing
- From: David B Thompson <DBT@xxxxxxxxxxxxxxxxxxxx>
- To: tcug@xxxxxxxxxxxxx
- Date: Mon, 23 Sep 2002 20:07:00 +0100
There is a need to have Suplementary Earth Bonding to extraneous metallic
parts, which is a different requirement to Equipotential Bonding. These do
not need to be 10mm and can be taken off a nearby earthing point. They are
simply there to ensure no voltage exists between the various items.
Dave Thompson
Mott MacDonald
===== Original Message from tcug@xxxxxxxxxxxxx at 23/09/02 03:48
>Most of our problems have been on, for example shuttle sites and have long
>cable runs.
>
>I agree with your comments with armour earthing to allow safe disconnection
>times, but
>for situations with long runs using 1.5mm cores, ELIs can run a little high
>even if very good at source
>and as we have to provide equipotential bonding to all exranious conductive
>parts poles etc
>what are the options ?
>
>> -----Original Message-----
>> From: David B Thompson [SMTP:DBT@xxxxxxxxxxxxxxxxxxxx]
>> Sent: Monday, September 23, 2002 7:05 PM
>> To: tcug@xxxxxxxxxxxxx
>> Subject: [TCUG] Re: Installation Earthing
>>
>>
>> ===== Original Message from tcug@xxxxxxxxxxxxx at 23/09/02 01:57
>> >Provided armoured cable is properly terminated with good quality glands
>> ,it
>> >is our experience that this will result in ELI readings well within the
>> >maximums allowed by the regulations .This is backed up by a preventative
>> >maintenance routine which acts as a "catch all" for issues such as
>> corrosion
>> >,movement due to vibration etc ,this of course applies irrespective of
>> the
>> >type of cabling used .I agree with Ian Wallis that this method properly
>> >applied as above has stood the test of time .
>> >Reg Hill
>> >Cardiff County Council
>> >
>> >-----Original Message-----
>> >From: Wallis, Ian [mailto:Ian.Wallis@xxxxxxxxxxxx]
>> >Sent: 20 September 2002 15:32
>> >To: 'tcug@xxxxxxxxxxxxx'
>> >Subject: [TCUG] Re: Installation Earthing
>> >
>> >
>> >In my experience those who "believe" that there is a problem just cost
>> >themselves a lot of money. Do your ELI tests show a problem? In my
>> >experience using the armouring as an earth still gives readings far lower
>> >than the maximum allowed by the regs even when 25 years old even with
>> >surface corrosion.
>> >
>> >Ian Wallis
>> >Derby City Council
>> >
>> >
>> >
>> >-----Original Message-----
>> >From: Probert, Norman (Environmental Services)
>> >[mailto:NProbert@xxxxxxxxxxxxxxxxxxxxx]
>> >Sent: 20 September 2002 15:25
>> >To: tcug@xxxxxxxxxxxxx
>> >Subject: [TCUG] Installation Earthing
>> >
>> >
>> >
>> >
>> >We have been looking into providing better earth continuity at
>> >installations, we believe that the existing method using the armouring is
>> no
>> >longer sufficient and can lead to high readings therefore a separate 10mm
>> >earth conductor should be used from each pole. There are two options
>> either
>> >build this into the existing cable or install a separate armoured cable
>> >containing earth only. Our problem is that this is a non standard cable
>> and
>> >would have to be purchased in significant quantities 5,000 metres at a
>> go,
>> >we are finding it hard to convince our suppliers that they could offer
>> this
>> >cable to others and we are also reluctant to make the purchase ourselves.
>> >
>> >My question is
>> >
>> >A Does anybody else agree that it is a good idea (if enough took it up
>> it
>> >could become standard instead of special).
>> >
>> >B Does anybody currently use this type of cable already and if they do
>> who
>> >makes it.
>> >
>> >C Has anybody got a better idea
>> >
>> >
>> >Norman Probert
>> >Senior Engineer Traffic Control Systems
>> >
>> >Tel 01905-766822
>> >Email nprobert@xxxxxxxxxxxxxxxxxxxxx
>> <mailto:nprobert@xxxxxxxxxxxxxxxxxxxxx>
>> >
>> >
>> >
>> >**********************************************************************
>> >Privileged/Confidential information and/or Copyright Material
>> >may be contained in this email. The information and Material
>> >is intended for the use of the addressee(s) only.
>> >
>> >If you are not the addressee or the person responsible for
>> >delivering it to the intended addressee(s), you may not copy or
>> >deliver it to anyone else or use it in any unauthorised manner.
>> >To do so is prohibited and may be unlawful. If you receive this
>> >email by mistake, advise the sender immediately by using the
>> >reply facility in your email software.
>> >
>> >Any views or opinions presented are solely those of the author
>> >and do not necessarily represent those of Worcestershire County
>> >Council.
>> >
>> >Although this email and attachments are believed to be free of any
>> >virus or other defects which might affect any computer or IT systems
>> >into which the are received, no responsibility is accepted by
>> >Worcestershire County Council for any loss or damage arising in any
>> >way from the receipt or use thereof.
>> >
>> >**********************************************************************
>> >-----------------------------------------------------------
>> >A message from the TCUG mailing list. For information about
>> >the list visit //www.freelists.org/webpage/tcug
>> >
>> >
>> >**********************************************************************
>> >The views expressed in this email are personal and may not
>> >necessarily reflect those of Derby City Council, unless explicitly
>> >stated otherwise
>> >
>> >This email, and any files transmitted with it, are confidential and
>> >intended solely for the use of the individual or entity to whom they
>> >are addressed. If you have received this email in error, please
>> >notify me immediately.
>> >
>> >If you are not the intended recipient of this email, you should not
>> >copy it for any purpose, or disclose its contents to any other
>> >person.
>> >
>> >This footnote also confirms that this email message has been
>> >swept by MIMEsweeper for the presence of computer viruses.
>> >However, we cannot accept liability for viruses that may be in
>> >this e-mail. We recommend that you check all e-mails with an
>> >appropriate virus scanner.
>> >
>> >www.mimesweeper.com
>> >**********************************************************************
>> >
>> >
>> >-- HTML Attachment decoded to text by Ecartis --
>> >
>> > RE: [TCUG] Installation Earthing
>> >
>> >
>> >
>> >In my experience those who "believe" that there is a problem just cost
>> >themselves a lot of money. Do your ELI tests show a problem? In my
>> >experience using the armouring as an earth still gives readings far lower
>> >than the maximum allowed by the regs even when 25 years old even with
>> >surfacecorrosion.
>> >
>> >Ian Wallis
>> >Derby City Council
>> >
>> >
>> >
>> >-----Original Message-----
>> >From: Probert, Norman (Environmental Services)
>> >[mailto:NProbert@xxxxxxxxxxxxxxxxxxxxx[1]]
>> >Sent: 20 September 2002 15:25
>> >To: tcug@xxxxxxxxxxxxx
>> >Subject: [TCUG] Installation Earthing
>> >
>> >
>> >
>> >
>> >We have been looking into providing better earth continuity at
>> >installations, we believe that the existing method using the armouring is
>> no
>> >
>> >longer sufficient and can lead to high readings therefore a separate 10mm
>> >earth conductor should be used from each pole. There are two options
>> either
>> >build this into the existing cable or install a separate armoured cable
>> >containing earth only. Our problem is that this is a non standard cable
>> and
>> >would have to be purchased in significant quantities 5,000 metres at a
>> go,
>> >we are finding it hard to convince our suppliers that they could offer
>> this
>> >cable to others and we are also reluctant to make the purchase ourselves.
>> >
>> >My question is
>> >
>> >A Does anybody else agree that it is a good idea (if enough took it up
>> it
>> >could become standard instead of special).
>> >
>> >B Does anybody currently use this type of cable already and if they do
>> who
>> >
>> >makes it.
>> >
>> >C Has anybody got a better idea
>> >
>> >
>> >Norman Probert
>> >Senior Engineer Traffic Control Systems
>> >
>> >Tel 01905-766822
>> >Email nprobert@xxxxxxxxxxxxxxxxxxxxx
>> ><mailto:nprobert@xxxxxxxxxxxxxxxxxxxxx[2]>
>> >
>> >
>> >
>> >
>> >**********************************************************************
>> >Privileged/Confidential information and/or Copyright Material
>> >may be contained in this email. The information and Material
>> >is intended for the use of the addressee(s) only.
>> >
>> >If you are not the addressee or the person responsible for
>> >delivering it to the intended addressee(s), you may not copy or
>> >deliver it to anyone else or use it in any unauthorised manner.
>> >To do so is prohibited and may be unlawful. If you receive this
>> >email by mistake, advise the sender immediately by using the
>> >reply facility in your email software.
>> >
>> >Any views or opinions presented are solely those of the author
>> >and do not necessarily represent those of Worcestershire County
>> >Council.
>> >
>> >Although this email and attachments are believed to be free of any
>> >virus or other defects which might affect any computer or IT systems
>> >into which the are received, no responsibility is accepted by
>> >Worcestershire County Council for any loss or damage arising in any
>> >way from the receipt or use thereof.
>> >
>> >**********************************************************************
>> >-----------------------------------------------------------
>> >A message from the TCUG mailing list. For information about
>> >the list visit //www.freelists.org/webpage/tcug[3]
>> >
>> >**********************************************************************
>> >The views expressed in this email are personal and may not
>> >necessarily reflect those of Derby City Council, unless explicitly
>> >stated otherwise
>> >
>> >This email, and any files transmitted with it, are confidential and
>> >intended solely for the use of the individual or entity to whom they
>> >are addressed. If you have received this email in error, please
>> >notify me immediately.
>> >
>> >If you are not the intended recipient of this email, you should not
>> >copy it for any purpose, or disclose its contents to any other
>> >person.
>> >
>> >This footnote also confirms that this email message has been
>> >swept by MIMEsweeper for the presence of computer viruses.
>> >However, we cannot accept liability for viruses that may be in
>> >this e-mail. We recommend that you check all e-mails with an
>> >appropriate virus scanner.
>> >
>> >www.mimesweeper.com
>> >**********************************************************************
>> >
>> >
>> >--- Links ---
>> > 1 mailto:NProbert@xxxxxxxxxxxxxxxxxxxxx
>> > 2 mailto:nprobert@xxxxxxxxxxxxxxxxxxxxx
>> > 3 //www.freelists.org/webpage/tcug
>> >
>> >-----------------------------------------------------------
>> >A message from the TCUG mailing list. For information about
>> >the list visit //www.freelists.org/webpage/tcug
>> >
>> >
>> >**********************************************************************
>> >Privileged/Confidential Information may be contained in this message. If
>> you are not the
>> addressee indicated in this message (or responsible for delivery of the
>> message to such person), you may not copy or deliver this message to
>> anyone.
>> In such case, you should destroy this message and kindly notify the sender
>>
>> by reply email. Please advise immediately if you or your employer does not
>>
>> consent to Internet email for messages of this kind. Opinions,
>> conclusions
>> and other information in this message that do not relate to the official
>> business of the Council of the City and County of Cardiff shall be
>> understood as neither given nor endorsed by it. All e-mail sent to or from
>>
>> this address will be processed by Cardiff County Councils Corporate E-mail
>>
>> system and may be subject to scrutiny by someone other than the addressee.
>> >**********************************************************************
>> >Mae'n bosibl bod gwybodaeth gyfrinachol yn y neges hon. Os na chyfeirir
>> y neges atoch chi'n
>> benodol (neu os nad ydych chi'n gyfrifol am drosglwyddo'r neges i'r person
>> a
>> enwir), yna ni chewch gopio na throsglwyddo'r neges. Mewn achos o'r fath,
>>
>> dylech ddinistrio'r neges a hysbysu'r anfonwr drwy e-bost ar unwaith.
>> Rhowch wybod i'r anfonydd ar unwaith os nad ydych chi neu eich cyflogydd
>> yn
>> caniatau e-bost y Rhyngrwyd am negeseuon fel hon. Rhaid deall nad yw'r
>> safbwyntiau, y casgliadau a'r wybodaeth arall yn y neges hon nad ydynt yn
>> cyfeirio at fusnes swyddogol Cyngor Dinas a Sir Caerdydd yn cynrychioli
>> barn
>> y Cyngor Sir nad yn cael sel ei fendith. Caiff unrhyw negeseuon a anfonir
>> at, neu o'r cyfeiriad e-bost hwn eu prosesu gan system E-bost
>> Gorfforaethol
>> Cyngor Sir Caerdydd a gallant gael eu harchwilio gan rywun heblaw'r person
>> a
>> enwir.
>> >**********************************************************************
>> >
>> >-----------------------------------------------------------
>> >A message from the TCUG mailing list. For information about
>> >the list visit //www.freelists.org/webpage/tcug
>> ===== Comments by DBT@JDT-BIRM (David B Thompson) at 23/09/02 10:52
>> I agree with Reg, that the use of a 10mm earth core would seem excessive.
>> Is
>> there some confusion over main equipotential bonding and Circuit
>> Protective
>> Conductor?
>>
>> The Main Equipotential Earthing conductor does need to be 10mm cable,
>> particularly when PME (TNCS) is used (6mm is permissible on TNS). However,
>>
>> the connections to signal poles have always been considered Final Sub
>> Circuits, which only need an earth core of the same size as the phase, if
>> within the same cable. It is also permissible to use the armour.
>>
>> The usual cause of poor line loop impedance is:
>>
>> Trying to cable too large an installation with too small cable cores.
>>
>> Poor maintenance or installation. I have found cable joints in the past,
>> where installers have connected 2 or 3 strands of armour into a connector
>> and cut the rest off.
>>
>> Dave Thompson
>>
>> Mott MacDonald
>>
>>
>> -----------------------------------------------------------
>> A message from the TCUG mailing list. For information about
>> the list visit //www.freelists.org/webpage/tcug
>
>
>**********************************************************************
>Privileged/Confidential information and/or Copyright Material
>may be contained in this email. The information and Material
>is intended for the use of the addressee(s) only.
>
>If you are not the addressee or the person responsible for
>delivering it to the intended addressee(s), you may not copy or
>deliver it to anyone else or use it in any unauthorised manner.
>To do so is prohibited and may be unlawful. If you receive this
>email by mistake, advise the sender immediately by using the
>reply facility in your email software.
>
>Any views or opinions presented are solely those of the author
>and do not necessarily represent those of Worcestershire County
>Council.
>
>Although this email and attachments are believed to be free of any
>virus or other defects which might affect any computer or IT systems
>into which the are received, no responsibility is accepted by
>Worcestershire County Council for any loss or damage arising in any
>way from the receipt or use thereof.
>
>**********************************************************************
>-----------------------------------------------------------
>A message from the TCUG mailing list. For information about
>the list visit //www.freelists.org/webpage/tcug
jdt
Canterbury House, 85 Newhall Street, Birmingham B3 1LZ
Tel +44(0)121 237 4016; Fax +44(0)121 237 4003
__________________________________________________
Mott MacDonald Ltd
Registered in England no. 1243967
Registered office St Anne House, 20-26 Wellesley Rd, Croydon, CR9 2UL
-----------------------------------------------------------
A message from the TCUG mailing list. For information about
the list visit //www.freelists.org/webpage/tcug
Other related posts:
