Bonding central heating

[Alan42]

Hi all, I've just spent most of my Sunday trying to answer this question: what bonding is required for a gas central heating system where some pipes are under the suspended timber floor? I have to consider this in connection with a consumer unit change, the gas and water main bonding is in 10mm which was (presumably) OK'd by the sparky who wired the new kitchen a few months ago and I now have to renew the board with a nice big Crabtree one with 2 - 30mA RCDs. The system had a 4-way and a seperate 1-way rewireable fuse board, both fed by a 30mA RCD. I see it like this: the boiler has a cpc in the flex that connects it. The pipes under the floor are clipped to timber joists where visible. 411.3.1.2 requires main protective bonding of central heating pipes where they are extraneous conductive parts, ie liable to introduce earth potential into the building, so if the floor were concrete I reckon all buried pipes would need bonding with a 10mm cpc. Now, the pipes in this house are nicely insulated with nylon clips and timber joists as far as I can see, but just in case there is a possibility of contact with the sub-floor I propose to connect the 2 pipes that come out of the floor with clamps to a spare loop of the existing main bonding cable that runs past them. There is plenty of slack in the cable, so I can do it without cutting. Am I right? Many thanks in anticipation.

 

[ezzzekiel]

post was a bit too long for me to read i only have little eyes but between the lines if you have rcd and main bonds in place then supp bond is not necc, although i would always add it as a matter of course..

 

[Guest123]

Hi.

Basically all that is required is a main bond to incoming water service, and a main bond to incoming gas service.

I also cross bond hot and cold water pipes and also flow and return heating pipes at the boiler position, just something I do.

Cheers

 

[spark1]

Alan,
Supplementary Bonding Not required at Boiler as I think .from your post,You already are aware of....
Main Equipotential Protective Bonding to c/heating pipes not required, as pipework not in contact with extraneous conductive part as far as you can reasonably ascertain....I personally would not additionally bond as you suggest doing. dont forget you can always mention this reasoning on the EIC if you have any concerns on the matter.


spark 1