Main bonding flow and return to oil boiler

[davesparks]

And if the flow and return have their own main bond back to the MET as stated [Which is unusual] I'd be inclined to just cross bond from them to the oil feed near the boiler in 10mm.

Not unusual in this situation where they are strictly speaking extraneous parts entering the installation.

I think to take the regulations absolutely literally they should be bonded as extraneous parts entering the outbuilding too, but since those very pipes can probably be used as a bonding conductor anyway it's fair to accept them as they they are.

 

[Dave OCD]

Yes they'll be at least 22mm pipes possible even bigger so between the two of them they'll have a lower resistance and a lot more csa than 10mm earth cable.

 

[BLBelfast]

Yeah the 10mm main bonding to the flow and return is definitely there as i wired it myself.

Thanks for taking the time and giving your advice. And i will bond to the incoming oil line in 10mm from the garage cu then though it also doesnt come into contact with the ground so not sure what the theory of this is. It's literally a 2m pipe from tank to boiler.

 

[davesparks]

Yeah the 10mm main bonding to the flow and return is definitely there as i wired it myself.

Thanks for taking the time and giving your advice. And i will bond to the incoming oil line in 10mm from the garage cu then though it also doesnt come into contact with the ground so not sure what the theory of this is. It's literally a 2m pipe from tank to boiler.

The most popular theory at the moment is to test it to establish whether or not is extraneous to establish whether or not main bonding is required.
Personally I interpret ten regulations slightly differently, but I'm in the minority with that opinion and am probably wrong.

 

[Wilko]

No worries, though I am inclined to ask the same question again. Metal pipes can be used as a means of earthing if they are suitable (permission of the owner, size, reliability etc etc)

Hi - just reading through 542.2.6 and it seems a gas or flammable liquid pipe should not be used as an earth electrode, but I may have misunderstood (?).

 

[davesparks]

Hi - just reading through 542.2.6 and it seems a gas or flammable liquid pipe should not be used as an earth electrode, but I may have misunderstood (?).

You're right, no gas or oil pipe can be used as a protective conductor or earth electrode.