Main Bonding?

[ultinator]

Does main bonding in every circumstance always need to be under 0.05. main bonding in a house where the main water was moved has 10mm cable but resistance of 0.25 ohms!!>>

 

[Technician]

Gn 3 says so.  Any one length of continuous bonding

conductor to be less than 50 mOhm.

HOW was that conductor tested?

 

[ultinator]

long lead from MET to pipe in kitchen, leads zeroed. the electrics were a bit bodged from previous works. got 2 supplementary bonds at 6mm and 3 10mm bonds?. a breaker that has 10mm protruding copper from its otherwise unused terminal. connector blocks everywhere. a 16a mcb instead of a 6a.and it doesnt fit correctly. no installation certs even though hosue had  an extension larger than the orignial house and board unlabelled. oh and outside sockets with no rcds.....this list goes on

 

[Technician]

Use table in On Site Guide on page 182 to calculate

what size conductor SHOULD be.

 

[ultinator]

it should be a 10mm with resistance of less that 0.05 ohms ideally given the length of run

 

[Bruspark]

Is there a connector block junction in the bonding cable by any chance ?

 

[ultinator]

cant see under the floors really, at all. At least not atm. would like to think not but u neva no

 

[ultinator]

can the water bonding be at any/closest water points?

 

[Technician]

Just a note on this;  Gn 3 states that testing is to be

carried out where practicable.  Reg 612.2.1.

If the calculation for conductor size is carried out correctly,

and a size is between any two sizes in that table, then,

obviously, the next size up is used.

Re Ultinator's point, supplementary bonding is not always

required.  See Reg. 701.415.2.