CORGI visit - queries on regs

I just has a Corgi round to do a landlord's gas safety certificate. He issued it, but pointed out two minor areas of concern which he says wants sorting - the gas hob needs an isolation valve (which can be in the void behind the built-in oven); and secondly, in said void there is an elbow in the gas pipework with compression fittings, which he wants replaced with a soldered elbow.
I didn't really think about it till after he'd gone; but (a) what's the point of having an isolation valve in an inaccessible location and (b) if there's a problem using compression fittings with gas... don't isolation valves usually have these anyway?
He also pointed out that if I didn't want to fail my electrical inspection, I would need to fit earth bonding across the 5 copper pipes entering and leaving the boiler (which is neither in the bathroom or kitchen). That one's news to me... is he correct, anyone?!
David
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On Thu, 09 Dec 2004 19:14:56 +0000, Lobster wrote:

The issue is that the hob requires an isolation valve. I'm not sure what the industry standard category would be if there isn't one. NCS I would think, just possibly AR. See FAQ.
The compression joint is about accessibility it would be poor practice to (say) put one under a wooden floor. My view is that a compression joint behind a built-under oven is OK. If the others in the game read this how would they view things?

I beleive so. This is more about making sure that the CH pipes are bonded to earth than supplementary bonding in a wet location - IIRC.
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Ed Sirett - Property maintainer and registered gas fitter.
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Thanks for this Ed - checked the FAQ but can't find NCS - wassat then?! (also couldn't find a mention of the need for an isolation valve but as it's your FAQ I'm sure you're right!)

Just seemed to me an odd stipulation if he's *telling* me to fit another compression fitting (ie on the isolation valve) in the same place where he's told me to remove an elbow because it *has* a compression fitting...
David
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<Snip Gas part>
He also pointed out that if I didn't want to fail my electrical inspection,

There is usually no reason to bond all the copper pipes that enter/leave the boiler together. Are you sure that the CORGI guy is not asking for the gas supply to be earth bonded?
Adam
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inspection,
and
That
bonded
the
At the last visit of my CORGI engineer, he advised bonding all the copper pipes from the gas boiler. Even wrote on the certificate that the householder would carry out remedial work necessary. -- troubleinstore Email address in posting is ficticious and is intended as spam trap Personal mail can be sent via website. http://www.tuppencechange.co.uk/contact.php
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Definitely... the gas supply is already properly earth-bonded, which he also checked - he was pointing to the 5 pipes (as identified in Christian's reply) entering/leaving the boiler.
(All but the gas pipe were actually already cross-bonded in the bathroom next door, but that didn't help, apparently!)
David
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On Fri, 10 Dec 2004 10:40:53 GMT, "Lobster"

He obviously doesn't know what he's on about then. There is no requirement to cross bond the pipes by the boiler.
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SJW
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It certainly doesn't make sense to me. If all services are cross bonded at the entry point, and a boiler is earthed by its normal electrical connection, why cross bond pipework at it? And as well as cross bonding, has it got to be run back to the main local earth?
Just curious.
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Wiring regs require main equipotential bonding for the CH pipes, and this "shall be connected to the main earth terminal at the origin of an installation".
If they are not currently, this is probably this is what the Corgi is barking about
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On Fri, 10 Dec 2004 19:13:04 GMT, "Coherers"
No they don't.
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strung together this:

Wanna bet?
413-02-02
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strung together this:

Yep. What the odds?
Adam
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strung together this:

413-02-02: "In each installation, main equipotential bonding conductors (see table) complying with Section 547 shall connect to the main earthing terminal for that installation's extraneous-conductive-parts including the following: water service and gas installation pipes; other service pipes and ducting; central heating and air conditioning systems; exposed metallic structural parts of the building; the lightning protective system'.
What odds would you like?
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(see
and
I think you are taking this too literally. The meaning you are proposing it has would require every separate piece of central heating pipe to need it's own bonding wire as you are saying the compression joint doesn't provide guaranteed earth continuity. This is obviously a nonsense. And if the joints around the system have guaranteed conductivity then so do those at the boiler.
Indeed implemented this strictly, every RSJ would need an earthing terminal which would be insane.
Also this paragraph is out of date - lightning protective systems do not now go to main earth - this destroys modems and the like - they must have their own separate ground connection.
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if
I don't really buy the compression fitting stops continuity argument. If they interpreted it like that, supplementary bonding would be mad too. For stuff like this, you don't need a 100% guarantee of continuity, just something to improve the odds. All I think you need to do is put a couple of straps on and take it back to the earth block. Just like with the gas. No more, no less. Really not onerous. Honest.

terminal
Only if exposed.
Actually, there was a recent case where a workman was killed because there was live buried metal work and the wiring committee were discussing if this had implications for future changes - it only applies currently to exposed metalwork. Briefly discussed in here:
http://www.iee.org/Publish/WireRegs/IEE_Thin_walls.pdf
See this bit on the right of page 1: "The previous guidance of the joint committee has been that steel framework would generally require neither earthing nor main bonding provided insulated and sheathed cables were used ...." I don't think they will change it though, 'cos as you say it would be mad.

now
their
Interesting, don't know anything about them. But I would have thought "lightning protective systems" would be outside the building anyway, so would not need to be covered anyway. Odd.
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I've yet to see anyone earth bond cast iron guttering. Will this fail an inspection? Oh - and Crittall windows?
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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Outside, so hopefully you would be okay. I think the equipotential zones are only required inside the building

Now that is an interesting thought. I read something somewhere about the danger of cross-bonding metalwork that was exposed to both the inside and the outside because, although it is safer for those inside the zone, it can create a hazard to people outside of it.
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can
Which actually raises an issue in mine and many other cases - boilers are often external to the house.
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strung together this:

(see
and
What have you got? I'll take the lot apart from the wife and kids.
Unless the CH is for some reason an extraneous-condutive part I will take any odds.
Adam
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It is. Almost all metal pipework will be. If it might be connected to earth somehow.
Extraneous conductive part: "Metalwork that is not part of the electrical installation, and which is liable to introduce a potential, generally earth potential" ( c.f. Exposed conductive part. )
Here, have a look at this thread on the IEE forum discussing whether a suspended ceiling (!) is such a part:
http://www.iee.org/FORUMS/messageview.cfm?PrintVersion=true&catid=5&threadid (30
(Verdict, No - fortunately). But it goes to show what we are dealing with.
Are you really sure you want to go "All in" on this one ??? I've got a big stack of chips here..... ;-)
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