They would not require bonding under the main equipotential bonding rules
as, being insulated, they do not qualify as "extraneous conducting parts" -
the defintion for which requires that they are "liable to introduce a
potential". (They would float)
However, a whole metal staircase indoors would require a main bond in my
Ah. My original text is a bit ambiguous. Sorry.
The bonding needs to be *between* the CH pipes and the origin of the
installation (i.e. CU etc.).
The regs don't specify where the bonding should be attached to the CH
pipework (unlike the gas service), but flow & return near the boiler seems
as good a place as anywhere. And under the floorboards is best
I have absolutely no need to, and in the absence of you putting forward
evidence to the contrary, I would suggest that perhaps it is someone a bit
closer to home in need of some technical training.
As you don't seem to be interested in the regulations, perhaps you would be
interested to read what Marks says in the "Handbook on IEE Wiring
Main Equipotential Bonding
Extraneous conductive parts that extend throughout the installation shall be
connected to the main earth terminal at the origin of an installation by
main equipotential bonding conductors, including the following items:
1. Main water pipes.
2. Gas installation pipes.
3. Main service pipes and ducting.
4. Central heating and air conditioning systems.
5. Exposed metal parts of the building structure.
6. The lightning conductor system.
7. Metallic sheath of telecommunications cable ( subject to the owner's or
8. Extraneous conductive part which is in direct contact with earth.
413-02-02 and the Electricity Supply Regulations.
Trevor E. Marks has written courses on behalf of the IEE, has been chair of
IEE technical sections and is a well known respected technical author who
has written extensively on electrical subjects.
So what we have is that you think:
1) The clear quote from the IEE wiring regs is wrong.
2) A standard, well-known text, which you appear never to have heard of, is
3) A document on the IEE web-site, written by Paul Cook ( author of the IEE
publication "Commentary on IEE Wiring Regulations" and who gives papers on
the subject at international seminars) is wrong.
4) Engineers discussing it on the IEE web site who are also wrong.
I am sorry you don't agree with the IEE, but I am afraid they make the
regulations. Take it up with them.
Even if we ignore the contentious items, he is wrong on both the lightning
and telecomms points. These are serious mistakes.
There are errors in all standards. They are the work of teams of experts
usually volunteered by their companies who make a 'best-effort' on the task
in hand. I have contributed to many such forums in the telecomms fields and
I am sure these contain errors as well.
I'm an electronics engineer, not an electrician, and so a book on the wiring
regs don't come high on my list of preferred reading. I doubt if he has
heard of me either.
Quite possibly. I am often critiquing papers at seminars and find glaring
As a member of the IEEE I don't think I can get to these. But I'll see if
Don't agree with many things about the IEE, that's why I joined the IEEE 25
IEE Wiring regs have required bonding of lightning conductors for years.
I believe the BS on lightning conductors does too, but I don't have a
copy of it to see exactly what it says.
Many electricity suppliers will refuse to connect you to the supply if
you have bonded the lightning conductor.
Thus it has never been possible to make it conform to all the various regs.
Bonding of telecoms equipment is a horribly complex area, particularly
if you manufacture it for sale to multiple countries/PTTs. In just about
all cases, it has to be bonded, but it is often done at a single point
only, and kept isolated everywhere else. PTT's normally have their own
wiring regulations and are often exempt from national wiring regs and
EU directives on things like emissions.
Agreed - it is NEVER bonded at the terminal (user) end. To do so could mean
a lightning strike to your incorrectly bonded lightning rod, or just to the
overhead mains cable feeding your house, taking out a whole central office.
On the telecomms side he does say that it requires the permission of the
owner/operator which I doubt would be forthcoming. However, from the
*purely* electrical safety point of view (as opposed to concerns about how
you affect the telco equipment etc. ) it is consistent with the general
approach of bonding extraneous metal parts.
On the lightning point, as I said in an earlier post, I don't really see
where the need would arise anyway - but it *is* what the IEE Regs/OSG etc,
etc. say, as well as Trevor Marks. As for whether it should be removed, I
don't feel qualified enough to say for sure.
Ah! I don't have any problem with the possibility that the standards **may**
Indeed, I understand there were bits introduced into the 15th edition that
were taken out in the 16th because they were no longer believed to reflect
best practice. But, my problem is that I don't know the subject area in
enough detail to overturn the IEE view; nor do I have the time to get to the
point where I do. And if I am going to second guess a committee of
individuals brought together to produce the standard I am going to have to
be pretty expert in arguments for and against.
My other problem is that 7671 has a certain quasi-legal force. Deviating
from it and then trying to argue that it is wrong when you are being
sued/prosecuted won't get you far.
Sure, errors occur in papers. But for the error to have reached British
Standard status and to have gone unchallenged for over 12 years (a period in
which loads of amendments have been published) is not likely. They obviously
believe this is best practice.
Well, why don't you stir up the IEEE to put the case to the IEE about how
some clauses in the regs are liable to result in damage to electronic
equipment? I.e. get the IEEE to start representing the interests of *its*
members in the standards process. You can't blame the IEE for putting this
stuff in if nobody with a different perspective puts the other side.
You've hit the nail on the real problem. Until Jan 1st I can quite legally
argue that my way is better and provided I can convince an independent third
party chartered engineer of this I can do as I wish. But with Part P this
becomes a whole different issue. However if a BCO tells me to bond boiler
pipes on one of my developments then this may well be heading to court.
The IEEE is an US led 'worldwide' body who issue a set of regs based on 110v
mains. If they were allowed to enter the fray they would argue for this to
be adopted worldwide, probably not the discussion needed here.
On Fri, 10 Dec 2004 18:28:08 +0000 (GMT), "Dave Plowman (News)"
I have worked with some plumbers and electricians who haven't got a
clue so just bond everything in sight with 10mm so they've got to be
Unfortunately, in most cases they made it worse by mixing
Please reply to group or use 'usenet' in email subject
Well, I did cross-bond these 5 pipes - reckon it took less time to actually
do it than to read all the conflicting responses here :-) . However, from
what you're saying above, could it in fact be a Bad Thing to have fitted it?
Not sure about this issue of mixing of equipotential zones...
The sparks was round yesterday to do a full check on all my electrics in
fact, and didn't pass any comment on any of the cross-bonding.
GSIUR 26.6 - No person shall install an appliance without the means to
isolate it from the gas supply.
I'd agree with you there Ed. The issue of accessibility is a bit vague here
but since its adjacent to a screwed coupling to the hob itself the
implication to me at least is that it must be OK
Especially since the use of plastic water carrying parts in many boilers
effectively isolates one pipe from another via the boiler so its sensible to
ensure that the pipes are equipotentially bonded at this point
If you want to remove the hob, you also need to remove the built-in oven to
get at the fixings. So the isolation valve can be in the void at the back
of the oven without any fuss, because it's there when you'll need it the
most. In a case of a gas leak or severe hob fire, I'd rather everyone
turned the mains cock off at the meter, rather than trying to isolate each
The earth bonding is needed as part of the electrical safety requirements
for the boiler, that's if you or your electrician think it's needed or not.
If any faults occur in or around the boiler that could create electrical
arcing to the pipework, then the earth bonds are there to try and prevent
The electrical connection of the pipes by the boiler metalwork is an
incidental one which cannot be relied on for safety purposes eg. a fitting
may be bolted to a painted case and the fixing normally breaks through the
paint but it cannot be guaranteed to. Similarly for electrical links through
screwed plumbing connections with sealant applied. The bonding has the
sole purpose of being safety electrical connection so it makes a
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