earth bonding

[djlander]

hey guys

can some one help me as confused

a few people have said diffrent things about this

i am about to rewire a theatre building and it has 2 boilers, now do i need to have a main earth bond from the earth bar to the biolers? or can it just be cross bonded with its pipe work?

the gas a water will be bonded in 35mm as the supply is 75mm 200A

as i say diffrent people have said diffrent things so just woundered what you think?

cheers

chris

 

[Deleted member 9648]

The heating pipework will only require main bonding if it is an extraneous part,.....see the BRB for definition,(the key phrase is 'liable to introduce a potential,normally earth').....reg 411.3.1.2 lists extraneous conductive parts which require main bonding and this includes central heating systems , this is where the confusion arises. A normal heating system is generally wholly within the confines of the equipotential zone apart from the boiler flu and thus is not liable to introduce an earth and so is not an extraneous part.
'Cross bonding' pipework outside of special locations is another example of those myths which have persisted for decades and result in an awful lot of unnecessary work..........if the heating pipes enter a special location they may require supplementary bonding otherwise there is no requirement for 'cross bonding' and there never has been.