outside boiler rcd clarification

[littleeley]

if an oil boiler was in the kitchen of a house wired back in the seventies on pme earthing 6mm to bond water and oil line ect with no earth trip and the boiler was going to be replaced with an outside boiler as the boiler would have to be rcd protected is it ok to replace the fsu with a rcd protected fsu and would the earth bonding have to be up dated from 6mm to 10 mm as not sure were you draw the line with keeping it compliant when only alterations are required like adding exstra socket on ring rcd protect the ring ok do you need or should you up date the earth bonding your thoughts on this would be apreciated

 

[telectrix]

you do not need to upgrade bonding if you can prove that it's adequate to carry PEFC and is intact.

 

[malcolmsanford]

First off does the new outside boiler need to be RCD protection.

Reg 131.8 tells us that yes for alteration or additions then the earthing and bonding arrangements shall be adequate.

Reg 544.1.1 tells us that a bonding cable must be sized in relation to the neutral of the DNO supply cable and often than not that is a 10mm.

As Tel says you can risk assess the conductor and keep that 6mm, but IMO it is best to adhere to the regs as often as not.

 

[littleeley]

thanks for that tele but what about the fsu changing for rcd one ok to comply i just hate these grey areas that realy seem to depend on an interpretation