Does this pipework need bonding?

[Manator]

Thats a fist Steptoe and ADS agreeing.

 

[sellers]

It was NIC but it was in the regs black and White.

 

[ADS]

Thats a fist Steptoe and ADS agreeing.

No, we have actually agreed before - though you might have to go back a bit to find it.

I've even given him the odd 'Like' now and then.

---------- Post Auto-Merged at 00:03 ---------- Previous post was made at 00:01 ----------

It was NIC but it was in the regs black and White.

Where?

(And that's not 'sarcastic', I'm genuinely interested.)

 

[sellers]

I will dig it out tomorrow.

 

[steptoe]

I dont tend to disagree with ADS

we sometimes have differing views to the same end

 

[binky]

You cannot just omit cross bonding if all your bathroom circuits are RCD protection

catch up Sellers, been through that earlier. Hope the assessment went well.

---------- Post Auto-Merged at 07:59 ---------- Previous post was made at 07:50 ----------

If the pipe that re-enters the building is 'extraneous',

The discussion was whether the pipework in the bathroom was extraneous. And no I don't work to the regs cos I'm a completely dangerous **** who's trying to kill people

 

[springcrocus]

OK, apart from a few off-topic asides, this thread seems to have run its course so

Now the question. Does the new gas pipe in the bathroom also require bonding? (And why, or why not).

Anybody ready to commit to a reply yet?

I will say that I did provide an additional (main) bond to the new pipework. If I have created a problem, I can return and remove the bond. I do have reservations because it is TNC-S and I'm not smart enough to understand earth loops and neutral/earth circulating currents and their effects as well as, maybe, I should although I think that any adverse effects will be negligible.

C'mon, guys, lets have your opinions please.

 

[binky]

IMHO opinion the additional bond is probably unnecessary due to fact the pipe has more copper in it than the bond wire. No harm in having it but over a short span a bit pointless (bit different if down opposite end of factory perhaps?)

As for the bathroom, given full RCD protection, and meeting the relavant criteria in regs, I wouldn't have thought it necessary to bond at this point - again I would argue pipe has more copper than the bond wire ergo any fault current would travel down pipe first to your MEB anyway, though parallel path would help some more in meeting the stuff about touch voltages and disconnection times - regs book at work, otherwise I would quote section that applies (4 I think, but that might be previous version). Wander lead test from bathroom to MET (or did you post you've done that already)

 

[springcrocus]

Binky, thanks for your reasoned reply, and for sticking your head above the parapet. :Applaud

 

[binky]

Actually I am very concerned that no-one has counter argued the above - it's a bit weird :^O

 

[steptoe]

Id go with that,

not imo actually required due to the pipe already being bonded,[providing there is continuity on the pipe]

but I dont see there being any detrimental effects with having an additional bond.

 

[Sidewinder]

NO need to bond to the pipe the other end of the factory either!

If it is steel framed just bond to the steel either end! ; )

How far down the road of mods to you allow for the idiots?

What if someone decides to connect a 60A load to a 1mm sq lighting circuit you have just installed & sets the place on fire, is that your fault?...

 

[springcrocus]

NO need to bond to the pipe the other end of the factory either! If it is steel framed just bond to the steel either end! ; )

How far down the road of mods to you allow for the idiots?

What if someone decides to connect a 60A load to a 1mm sq lighting circuit you have just installed & sets the place on fire, is that your fault?...

Have you got your threads mixed up, Sidey? ?:|

 

[Sidewinder]

Post #48 by Binky

 

[springcrocus]

OK, mate, sorry. Just couldn't see the relevance to the OP. My bad.

 

[Revved Up Sparky]

That, Slips, is what I was hoping people would discuss. Is it correct to (main) bond at two separate points on a single service? Or is it correct to rely on the original bond even though, effectively, the service leaves the building at one point and re-enters at another?

Why does BS7671 state that we need to bond incoming services to the MET?. Those services are capable of introducing a different earth potential to the property than that earth potential which exists at the MET of the electrical installation, therefore an equipotential zone is required where there are no potential differences. Therefore the second gas pipe entry point is not going to introduce a different earth potential so IMHO it does not need bonding to the MET.

 

[ADS]

Actually I am very concerned that no-one has counter argued the above - it's a bit weird :^O

OK then.

As for the bathroom, given full RCD protection, and meeting the relavant criteria in regs, I wouldn't have thought it necessary to bond at this point - again I would argue pipe has more copper than the bond wire ergo any fault current would travel down pipe first to your MEB anyway,

Bonding has nothing to do with fault current travelling down anywhere..............it is to equalise 'potentials' on metalwork, within a location, under fault conditions - i.e. so there is no 'potential difference' between two accessible pieces of metalwork.

So, totally nothing to do with how fat your copper pipe is.

Why does BS7671 state that we need to bond incoming services to the MET?. Those services are capable of introducing a different earth potential to the property than that earth potential which exists at the MET of the electrical installation, therefore an equipotential zone is required where there are no potential differences. Therefore the second gas pipe entry point is not going to introduce a different earth potential so IMHO it does not need bonding to the MET.

But in the OPs scenario, it might do.

The gas pipe comes up from the ground into a 'T' (external).

One branch goes through the wall, under the kitchen floor and pops up by the cooker - where it is bonded.

The other branch goes straight up the outside wall and into the bathroom............so it might introduce a different potential into the bathroom.

Like I and a couple of others have said - the only way to know for certain if it's extraneous or not is to test it - if it's extraneous, then it requires bonding.

 

[binky]

OK then. Bonding has nothing to do with fault current travelling down anywhere..............it is to equalise 'potentials' on metalwork, within a location, under fault conditions - i.e. so there is no 'potential difference' between two accessible pieces of metalwork.

So, totally nothing to do with how fat your copper pipe is.

You would hope that fault current would mostly travel down CPC, but as leccy tends to travel down path of least resistance, then there is a possibility from appliances that some or all fault current may flow along pipework. There must also be some relationship between bond size and time it takes to equalise potential, so CSA of copper bond or pipes must have some effect hence we now use 10mm instead of 6mm like we used to many years ago.

 

[steptoe]

ok,

I'll throw another one into the mix,

what happens if you are on TNCS and your neighbour has a fault on a TT system, where is thier fault current going to go?

 

[binky]

No not again Steps

For those not familiar, Steps is about to educate you on the joys of TN-C-S versus TT. And it is indeed an education.... ROTFWL