Supplementary Bonding on a boiler

[IQ Electrical]

Who or what is/are eega?
Not this lot presumably:
East European Gas Analysis

Is this an oil or gas boiler.
If oil it will need 'cross bonding'. If gas it will not.

4mm will be okay. Just put your clamps on the pipes and go from clamp to clamp with cut lengths. No need for it to be continuous across all clamps.

Why do you make a distinction between gas and oil when both services are likely to meet the definition of an extraneous-conductive part and be bonded accordingly?

Also, where is there a stated requirement in BS 7671:2008 to 'cross bond' a boiler regardless of fuel type?

I've given this some thought and it would seem that the normal scenario is that main protective bonding will be applied to the gas/oil supply and to the water supply in the usual manner.
The pipework at the boiler (flow/return, dhw) will be connected to a metallic manifold of some sort at the boiler but will not meet the definition of extraneous-conductive parts.

However, the boiler will have a cpc to it's casing/chasis which will in turn have continuity to the manifold.
The pipes are all now 'linked' in effect and there is no further hazard created by 'cross bonding' but the excercise would appear to be pointless and is certainly not a requirement.

Any thoughts anyone?

 

[jaresquire]

In answer to original question, joining the cable in a crimp lug is accepted as 'continuous', at least was when I did 2391.

 

[Chr!s]

My view on this subject is this.

1) We Main bond all extraneous conductive parts to the met. So if the gas and water are bonded at the entry job done. Now if the gas or water along the route of the installation are insulated(due to fitting etc ) at some point, theres no requirement to cross bond at this point.

Now if the boiler is in a special location, then we need to consider supplementary bonding. Now if the system complys with the section within 701.415.2 parts 1-3 then theres no requirement to supplementary bond. Note effectiveness of connection may be assessed using 415.2.2.. if all complys no supplementary bonding required. If the installation doesn't comply then supplementary bonding may be required including possible cross bonding.

If the boiler is outside the special location the only other issue may be that extraneous doesn't always mean earth potential, the boiler itself has the ability to provide mains potential. So if the boiler was non rcd and fed via a 3 amp fuse then theres a risk that a fault could develop, mains potential could be introduced.

I dont see the above as a problem in this case, i see no requirement to cross bond the boiler unless its in a special location and dose not meet the requirements.

 

[Deleted member 9648]

Who or what is/are eega?
Not this lot presumably:
East European Gas Analysis

Is this an oil or gas boiler.
If oil it will need 'cross bonding'. If gas it will not.

4mm will be okay. Just put your clamps on the pipes and go from clamp to clamp with cut lengths. No need for it to be continuous across all clamps.

This is tosh I'm afraid....if you are going to post this sort of thing then you need to back it up with regulation numbers.
See post 18 for the correct information.

 

[liam b]

eaga are the guys paying, if they want cross bonding then do it regardless of where the boiler is, but cut lengths will do, ive been doing it for 4 years and never been pulled, also if the bath rad is a hard job then 'Bath Rad <0.05ohms' on your cert will do the trick as the cross bond is the same as bonding the bath rad

 

[bugsy]

I've just read all the post's and iv'e now got a headache,

 

[Gravid]

As it's unlikely to be a requirement of the BRB unless in a special location you can do it in wet string if you want to.

PMSL

The mythical art of cross bonding, seems it's making a come back, used to be able to make it look all curly and nice. No one ever could explain what it was for!

 

[PC Electrics]

If you check the manufacturers instructions that come with most oil boilers carefully, you will find that they instruct to cross bond the pipes at the boiler.
Example:
http://www.worcester-bosch.co.uk/ca...nstructions-for-greenstar-danesmoor-18-25.pdf
Page 7 of the book, Page 9 of the pdf

My understanding is that gas boilers are designed to British Standards which require that the boiler design guarantees electrical continuity of pipes at the manifold, thus negating the need for any cross bonding. The standards oil boilers are designed to makes no such requirement.

 

[jaresquire]

The continuous cable thing is only required for main protective bonding, not for supplementary.

 

[Gravid]

Well fair play there it is in black and white. Page 9 it is.

 

[jaresquire]

Of course always follow the manufacturer's instructions, except for door intercoms that are all written in Italian.

 

[sparky3366]

cheers liam, eaga can be a pain imho.

 

[telectrix]

same with kitchen sinks saying on the box " this product must be earthed "!!!! wtf.

 

[Engineer54]

You must always follow the manufacturers instructions, ....Is that not what everyone here keeps telling me?? hahaha!!!

 

[liam b]

cheers liam, eaga can be a pain imho.

i always think, 'whats the regs' followed by what do eaga want' and usually its 2 different things so end up doing them both. its just pleasing the man with his ticky boxes, really annoying