A DIY & home improvement forum. DIYbanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » DIYbanter forum » Do - it - Yourself » UK diy
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions.

boiler earthing?



 
 
LinkBack Thread Tools Display Modes
  #1  
Old January 4th 09, 03:45 PM posted to uk.d-i-y
external usenet poster
 
Posts: 495
Default boiler earthing?

Hello,

My old (oil fired) boiler had a 4mm^2 (ish) earth wire that ran from
the copper oil line back to the CU.

When the (non-oftec) plumber recently installed the new boiler, this
was not reconnected. I am having an oftec plumber coming to sign
everything off. Should I connect the earth before he comes and for my
own safety?

The boiler is earthed but only through the 6A flex.

In my last house the (gas) boiler had all the pipes cross bonded
immediately beneath it. None of the pipes going to or from this boiler
are. I don't think the CH pipes are earthed anywhere. Should they be?

Thanks,
Stephen.
Ads
  #2  
Old January 4th 09, 04:21 PM posted to uk.d-i-y
external usenet poster
 
Posts: 9,171
Default boiler earthing?

In article ,
Stephen writes:
Hello,

My old (oil fired) boiler had a 4mm^2 (ish) earth wire that ran from
the copper oil line back to the CU.


That's the service bonding.
Nowadays, it should be 10mm˛, IIRC.

When the (non-oftec) plumber recently installed the new boiler, this
was not reconnected. I am having an oftec plumber coming to sign
everything off. Should I connect the earth before he comes and for my
own safety?


I would have thought so, but I'm not expert in oil fired boiler
matters and any special requirements on them.

The boiler is earthed but only through the 6A flex.

In my last house the (gas) boiler had all the pipes cross bonded
immediately beneath it. None of the pipes going to or from this boiler
are. I don't think the CH pipes are earthed anywhere. Should they be?


They probably are in or adjacent to the bathroom -- that's where it's
normally done.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
  #3  
Old January 4th 09, 06:31 PM posted to uk.d-i-y
external usenet poster
 
Posts: 1,160
Default boiler earthing?


"Stephen" wrote in message
...
Hello,

My old (oil fired) boiler had a 4mm^2 (ish) earth wire that ran

from
the copper oil line back to the CU.

When the (non-oftec) plumber recently installed the new boiler, this
was not reconnected. I am having an oftec plumber coming to sign
everything off. Should I connect the earth before he comes and for

my
own safety?

The boiler is earthed but only through the 6A flex.

In my last house the (gas) boiler had all the pipes cross bonded
immediately beneath it. None of the pipes going to or from this

boiler
are. I don't think the CH pipes are earthed anywhere. Should they

be?

Thanks,
Stephen.


My OFTEC oil installer fitted my boiler but didn't bond the incoming
oil pipe, despite me querrying it. My NICEIC electrician certifying
the whole electrical installation insisted on 10mm bonding back to the
main earth point at the CU. Mind you I can (and actually have in a
previous posting) cite several errors of fact on his certificate !!!)
The boiler per se is only earthed via the copper plumbing which is
bonded and its own electrical connection 2.5mm earth.

AWEM

  #4  
Old January 4th 09, 09:12 PM posted to uk.d-i-y
external usenet poster
 
Posts: 15,390
Default boiler earthing?

Stephen wrote:

My old (oil fired) boiler had a 4mm^2 (ish) earth wire that ran from
the copper oil line back to the CU.


That would be the main equipotential bond for the incoming service (i.e.
oil pipe)

When the (non-oftec) plumber recently installed the new boiler, this
was not reconnected. I am having an oftec plumber coming to sign
everything off. Should I connect the earth before he comes and for my
own safety?


All incoming services in metallic pipes should be included in the main
equipotential bonding.

For TN-C-S and TN-S installations this is usually 10mm^2 earth single.
For TT it can be 6mm^2

See:

http://wiki.diyfaq.org.uk/index.php?...ng_and_Bonding

The boiler is earthed but only through the 6A flex.


That is fine.

In my last house the (gas) boiler had all the pipes cross bonded
immediately beneath it. None of the pipes going to or from this boiler
are. I don't think the CH pipes are earthed anywhere. Should they be?


Where is the boiler? Where was it in the last place?

Generally speaking you would expect to see supplementary equipotential
bonding in places that pose an special risk (bath / shower rooms, pool /
saunas etc). There is no harm in have supplementary bonding between its
connections, however there is in many cases no absolute requirement for
it. Note that supplementary bonds do not need to be either earthed, or
connected back to the main CU earth terminal.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
  #6  
Old January 7th 09, 12:46 PM posted to uk.d-i-y
external usenet poster
 
Posts: 495
Default boiler earthing?

On Sun, 4 Jan 2009 18:31:05 -0000, "Andrew Mawson"
wrote:

My OFTEC oil installer fitted my boiler but didn't bond the incoming
oil pipe, despite me querrying it. My NICEIC electrician certifying
the whole electrical installation insisted on 10mm bonding back to the
main earth point at the CU


My OFTEC chap didn't comment that it's not connected. However since
the wire is there I will connect it. I'll have to be careful though as
I assume the 10mm micorobore pipe is more easily damaged if I
overtighten the clamp.

Thanks.
  #7  
Old January 7th 09, 12:49 PM posted to uk.d-i-y
external usenet poster
 
Posts: 495
Default boiler earthing?

On Sun, 04 Jan 2009 21:12:29 +0000, John Rumm
wrote:

Where is the boiler? Where was it in the last place?

Generally speaking you would expect to see supplementary equipotential
bonding in places that pose an special risk (bath / shower rooms, pool /
saunas etc). There is no harm in have supplementary bonding between its
connections, however there is in many cases no absolute requirement for
it. Note that supplementary bonds do not need to be either earthed, or
connected back to the main CU earth terminal.


It is in the kitchen, exactly where the old one was. Thinking about it
it's all copper pipe around the boiler but after 2 metres it turns
plastic, so I'm not sure that bonding would do much, except in the
immediate area of the boiler.

Is supplemental bonding supposed to be 10mm^2 too? I am not going to
do it (unless you tell me otherwise) but I ask out of curiosity.

Thanks.
  #8  
Old January 7th 09, 02:15 PM posted to uk.d-i-y
external usenet poster
 
Posts: 15,390
Default boiler earthing?

Stephen wrote:
On Sun, 04 Jan 2009 21:12:29 +0000, John Rumm
wrote:

Where is the boiler? Where was it in the last place?

Generally speaking you would expect to see supplementary equipotential
bonding in places that pose an special risk (bath / shower rooms, pool /
saunas etc). There is no harm in have supplementary bonding between its
connections, however there is in many cases no absolute requirement for
it. Note that supplementary bonds do not need to be either earthed, or
connected back to the main CU earth terminal.


It is in the kitchen, exactly where the old one was. Thinking about it
it's all copper pipe around the boiler but after 2 metres it turns
plastic, so I'm not sure that bonding would do much, except in the
immediate area of the boiler.


In "special locations" (of which a kitchen is *not* one - part P lumps
it in with them, but the wiring regs do not), the question to ask, is
are the pipes capable of introducing a potential into the room from
elsewhere. In you case it sounds like the answer is "no".

To quote the OSG (16th edtn): "There is no specific requirement in BS
7671 to supplementary bond the following

kitchen pipes, sinks or draining boards

metal furniture in kitchens

metal pipes and wash hand basins in domestic locations
other than bathrooms."

Is supplemental bonding supposed to be 10mm^2 too? I am not going to
do it (unless you tell me otherwise) but I ask out of curiosity.


Where there is no mechanical protection for the bonding conductors,
4.0mm is commonly used. Where you are bonding a circuit protective
conductor, then you should not use a smaller CSA wire than that of the
CPC - however domestic wires with CPCs larger than 4.0mm are not common
(only 16mm^2 for T&E)

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Earthing, with a generator... Sparks UK diy 16 February 7th 08 02:45 PM
Earthing Again [email protected] UK diy 1 January 19th 06 11:38 PM
Yet more earthing.... Cicero UK diy 4 October 6th 05 09:23 PM
Earthing Sparks UK diy 17 December 8th 03 10:57 PM
Earthing Sparks UK diy 10 October 29th 03 01:27 AM


All times are GMT +1. The time now is 12:12 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.SEO by vBSEO ©2010, Crawlability, Inc.
Copyright ©2004-2014 DIYbanter.
The comments are property of their posters.