18th 544.1.2

[JohnW2]

I take isolation point to be the tap.

A further thought. The bit that concernes us starts off with ...

"Where there is a meter, isolation point or union..."

(it's removed the 'at that point' bit). ... what gas or water installation does not have 'an isolation point (tap/stopcock/whatever, if that's what it means) and 'a union' and what gas installation does not have a meter (some water installations obviously don't)? The " ...Where there is" seems essentially redundant!

Kind Regards, John

 

[EFLImpudence]

In that case, given that it now starts by referring explicitly to extraneous-c-ps, it's now 'alright' (albeit it could be clearer!), isn't it?

Yes, although, I think, one would still have to understand what one is doing.

 

[AlanE]

Note for information wiring regs not a legal document whereas GSIUR is.

Electricians argue come what may the above is a requirement gasmen have to comply with. Start another thread if need be but above are the facts we have to comply with.

 

[EFLImpudence]

To be accurate, only the first paragraph is a gas regulation.

The rest is waffle and dependent on preferably.

More importantly it would appear to differ from the actual law -
as is usual with the plethora of guides which abound and confuse everyone.

Also I have answered in the other thread.

 

[rsgaz]

above are the facts we have to comply with.

I see that is from the "Gas Industry Unsafe Situations Procedure" pdf (formerly TB001).

It's own webpage states it provides guidance. (taken over now by IGEM)

That document states near the beginning...

And, seeing as they reference clause 1.8...

 

[JohnW2]

Note for information wiring regs not a legal document whereas GSIUR is. .... Electricians argue come what may the above is a requirement gasmen have to comply with. Start another thread if need be but above are the facts we have to comply with.

This is getting very confusing, with the same messages/material being posted in two threads. For the sake of continuity (in this thread), I think it best that I reproduce here what I've just posted in the other thread ...

... per what I keep saying, I'm not convinced that the person/persons who wrote those gas regulations understood anything much about electricity. As I've been implying, the statement ...

The purpose of equipotential bonding is to ensure the gas installation remains safe under electrical fault conditions

... makes little sense to me, since it seems to me that the opposite is the case. As I have said, the effect of bonding a gas pipe is that, under certain electrical fault conditions, extremely high currents could flow in the gas pipe, potentially leading to considerable local heating or even sparks in ther gas pipe, particularly in the vicinity of joints/unions. I would therefore have said that bonding a gas pipe does quite the opposite of "ensuring the gas installation remains safe under electrical fault conditions"!

As has been said, the gas pipework will almost always be connected to earth via the CPCs ('earth wires') feeding boilers, CH pumps and motorised valves etc., so the risk to which I refer already exists to some extent. However, adding bonding will, as far as I can see, make the situation appreciably less safe (gas-wise) by increasing the fault current.

If, as is commonly the case, the gas supply pipe does qualify as an extraneous-c-p then, electrically speaking, bonding is essential (to reduce the risk of electric shock), even if the result is to make the gas installation less safe.

Kind Regards, John

 

[ban-all-sheds]

Note for information wiring regs not a legal document whereas GSIUR is.

[ ]

Electricians argue come what may the above is a requirement gasmen have to comply with. Start another thread if need be but above are the facts we have to comply with.

Indeed - but think about what it actually says.

It is talking about equipotential bonding, and that is applied to extraneous conductive parts, not to any pipes come what may.

That guidance does not mean that bonding conductors have to be attached to the incoming pipework of all gas installations.

 

[333rocky333]

From Elecsa

20181011_124806

• 333rocky333
• 11 Oct 2018

 

[JohnW2]

From Elecsa

At least they seem to understand. Maybe they should offer their services to those who write gas regulations/guidelines/checklists!

Kind Regards, John

 

[securespark]

Yeah, I take isolation point to be (generally) the gas meter cock.

What I'm not sure about is this: what if the incoming visible water pipe is copper but the underground service is PE, but you can't see this part?

 

[ban-all-sheds]

Where does it transition - before it enters the equipotential zone, or after?

 

[JohnW2]

What I'm not sure about is this: what if the incoming visible water pipe is copper but the underground service is PE, but you can't see this part?

I suppose one has to satisfy oneself that one knows whether there is continuity to earth from that incoming visible water pipe. If one cannot achieve that by visual inspection, then one theoretically could ascertain by measurement, but that would require disconnection of the incoming pipe from the property's pipework (if metal) - since that would (again, if metal), almost inevitably have incidental paths to earth. If one cannot satisfy oneself by either visual inspection or measurement that it is not an extraneous-c-p, I suppose one would have to assume it was, and bond it.

With gas pipes, there will usually be less options - since, if one cannot reach a conclusion by visual inspection, disconnection of the incoming gas pipe from the property's gas pipework is unlikely to be a realistic option.

Kind Regards, John

 

[EFLImpudence]

What I'm not sure about is this: what if the incoming visible water pipe is copper but the underground service is PE, but you can't see this part?

Is that likely?

That is - would/could the gas company make the joint somewhere that was not accessible/visible?

 

[ban-all-sheds]

Iwould/could the gas company make the joint somewhere that was not accessible/visible?

Not according to Elecsa?

 

[JohnW2]

Is that likely? ... That is - would/could the gas company make the joint somewhere that was not accessible/visible?

Secure was actually talking about a water supply pipe.

However, I think one possible difficulty arises from the fact that it seems that some water and gas supply pipes are metal covered/coated in plastic. When one of those goes into a joint and a metal pipe comes out of the other side of the joint, it may not be obvious whether the upstream supply pipe is metal or plastic.

Kind Regards, John