Gas and water bonded together with a broken conductor?

[HappyHippyDad]

Evening everyone..

I have just undertaken an EICR and there is 6mm bonding to both water and gas at the correct points (within 600mm of entering building), however they must be joined somewhere as there is only one 6mm in the CU. I believe this would be ok if the conductor was unbroken but seeing as though it has to be broken somewhere (cant find it) I am unsure how to code it?

I would think C3?

Ps.. Its a TT.

 

[Octopus]

There is no reg saying it has to be continuous. Best practice says it should be! Not convinced I'd code it at all. Tin hat on.

 

[Plonker 3]

If you have proved there is a joint, but the continuity reading is under 0.05 the I would go with C3 and futher investigation, as how can you be certain the correct size cable is used along the whole length of the conductor?

 

[HappyHippyDad]

If you have proved there is a joint, but the continuity reading is under 0.05 the I would go with C3 and futher investigation, as how can you be certain the correct size cable is used along the whole length of the conductor?

Very good point! The incoming gas is one side of the kitchen door, the incoming water the other. I think it unlikely a different CSA has been used in such a small length of run, but even if it was I believe 4mm is ok for a TT, so unless they've joined it with a bit of 1mm I'm erring towards Murdoch's advice.. but... when I've finished the EICR (I'm very slow plus its a 5 bed OLD house with lots of questionable DIY electrics) I think I'll investigate a bit more anyway! :smiley2:

 

[HappyHippyDad]

There is no reg saying it has to be continuous. Best practice says it should be! Not convinced I'd code it at all. Tin hat on.

Thanks Murdoch,

You're very thorough and do things by the book so if you say it's probably not a code then it almost defnitely isn't! :smiley2:

 

[spark 68]

Hi HHD,
apart from PME,the main protective bonds shall be no less than half the Earthing conductor, and in any case no less than 6mm^, 544.1.1

 

[HappyHippyDad]

Hi HHD,
apart from PME,the main protective bonds shall be no less than half the Earthing conductor, and in any case no less than 6mm^, 544.1.1

Hi Spark68..

I was taught 6mm to be the minimum for bonding, but if you look at page 41 (table 4.4 (ii) )in the OSG it suggests that 4mm is acceptable for a TT(or even 2.5mm if mechanically protected)? There isn't a cross reference to BS7671 though!

And then underneath table 4.4(ii) there is a Note 2, it states reg 544.1.1 (i.e minimum of 6mm) - doesn't make sense!

 

[spark 68]

I think you may be mis-reading, the table 4.4 (i) in the OSG hhd, in mine (the light green part for MPB not PME) it is minimum 6mm^, table 4.4 (ii) refers to the Earthing conductor.

Ps.just trying to help

 

[HappyHippyDad]

I think you may be mis-reading, the table 4.4 (i) in the OSG hhd, in mine (the light green part for MPB not PME) it is 6mm^, table 4.4 (ii) refers to the Earthing conductor.

Ps.just trying to help

I'm not sure why I have these conversations with you Spark68, you're always right!! :redface:

It's late, I'm tired, I'm wrong!! Of course its referring to the Main Earth - I new that (He says in hindsight making himself look even more silly)... I'm going to bed!!

 

[spark 68]

I wasn't picking a fault, it is just if you are doing EICRs then it helps to have some guidance ( at least at first), and I happened to notice you said 4mm MPB was suitable for TT, better to correct you now rather than later.

We all had to start some where, at least you ask, I had another Spark to help me when I started.

We all need help from time to time.

 

[HappyHippyDad]

I wasn't picking a fault, it is just if you are doing EICRs then it helps to have some guidance ( at least at first), and I happened to notice you said 4mm MPB was suitable for TT, better to correct you now rather than later.

We all had to start some where, at least you ask, I had another Spark to help me when I started.

We all need help from time to time.

I should have put a smile S68! I know you wern't being picky, you were being very helpful and I value your posts. I'd much rather look a little silly but be right. Please keep correcting me..

 

[telectrix]

bear in mind, though that the 50% of main earthing conductor rule is based on the required csa of the MEC, as determined by use of the adiabatic. what i'm trying to say is that you migt have a 16mm MEC< but the adiabatic required only 6mm for the MEC, then 3mm is the min size for MBCs ( subject to not<6mm)

 

[Engineer54]

Bonding conductors have a minimum of 6mm even on a TT system. Let face it, on some of the TT installs we've been told about on here, the extraneous pipework will probably be providing the majority of the installations earthing provision!! ...lol!!!