Bonding

[switched on]

Hi i am doing a property atm a periodic and its got 6mm bonding obviously it needs 10mm but does it need upgrading i think it will be a code 3 etc iand cross bonding between the boiler pipes?, and if it has 16mm tails instead of 25mm on 100A fuse but i cant replace these without concerning the dno. Thanks for your advice just didn't know how far i should go with this

 

[spamwize2]

hi mate old properties used to have 16mm tails depends on the load now, cross bonding between pipes is old too, depends on the db and earthing
what are you doing?
if it all comes into the regs then fine have you checked zs and ze

 

[Forza]

For a PIR if you calculate the earthing conductor size using the adiebatic equation and all is good and as said the Ze and Zs results are satifactory it will be a code 4 as in does not comply with BS7671:2008

 

[Deleted member 9648]

Code 3 means 'requires further investigation'.....if you know the bonding conductor size it wont requiire further investigation.The minimum sze of the main bonding conductor will depend on the earthing system....6.0mm will be adequate on a TT.
Suggest you have a close look at bonding requirements in the BRB and OSG before recommending 'cross bonding boiler pipes'.

 

[Sintra]

Main Earthing Conductor

The minimum csa of the main earthing conductor must be determined by the adibiatic equation or selected from Table 54.7 543.1.1.
If the adibiatic equation is used, the minimum csa of the main earthing conductor must be 6mm 544.1.1.
Table 54.7 suggests a 16mm main earthing conductor for phase conductors with a csa of up to 35mm.
The csa of the main earthing conductor where PME conditions apply should be not less than that for a main protective bonding conductor (10mm) for the same installation 544.1.1.


Main Protective Bonding Conductors

For TN-S or TT systems the csa of main protective bonding conductors must be a minimum of 6mm and not be less than half the csa of the main earthing conductor.
544.1.1
For a PME system the csa of the main bonding conductors must not be less than that given in Table 54.8 ie a 10mm protective bonding conductor for a neutral conductor of 35mm or less. 544.1.1

 

[switched on]

yeah thats what i thought as an electrician did a pir on a property and said the boiler pipes need cross bonding and upgrading the earth but its all rcd protected so didn't see the need just wanted to check to make sure. you are saying that you don't need to cross bond the pipes anymore whats the logic behind this?? Thanks

 

[Deleted member 9648]

yeah thats what i thought as an electrician did a pir on a property and said the boiler pipes need cross bonding and upgrading the earth but its all rcd protected so didn't see the need just wanted to check to make sure. you are saying that you don't need to cross bond the pipes anymore whats the logic behind this?? Thanks

There was never any logic to it....it was just a myth.