Main Bonding and Cross Bonding question?

[ackbarthestar]

to achieve this it is recomended that the resitance of the conductor does not exceed 0.05ohms

Try BS7671 415.2.2 otherwise it would have stated it.

 

[ackbarthestar]

to achieve this it is recomended that the resitance of the conductor does not exceed 0.05ohms

apart from that the formula relates to the sizing of supplementary bonding conductors where disconnections times can not be met we are not talking about supp bonds but main bonds which is to ensure no difference in potential will occur between parts.

Lol, I suppose we are not talking about cross bonding then? Where did the disconnection times not being met come from?
I thought we are discussing the effectiveness of supplementary (cross) bonding to clamp the voltage below the maximum touch voltage even when disconnection times are met and where a fault might occur.

However, It is unlikely that cross bonding would be required for normal locations that are not within a bathroom. As long as the main protective bonding is in place and the disconnection times were met which is likely to be a lot less than 0.4s (0.01s).
The rule of thumb for the main protective bonding is as you say is 0.05 Ohms....

 

[ezzzekiel]

yup crossed wires (prob my fault for not reading all of thread)

 

[palmerelectrcal]

gas safe eng wouldnt connect gas meter until cross bonding in place from gas to boiler pipes.!!!!!!