EICR and Supplementary Bonding.

[Badged01]

Im happy to accept the views of anybody if this damn thread is closed and put to bed ...... its turned out to be like opening a whole can of worms!

 

[rattlehead85]

The End.....

 

[Geoffsd]

Nooooooooooooooooooooooooooooooo. You cannot end it on such a flawed statement.

Geoff or DSkelton is wrong merely that there interpretation seems to miss the point that section 7 of BS7671 asks for SB to be applied if the 3 conditions are not met.

You must apply 415.2 unless the three conditions are met.

This is not an interpretation; that is what it says.



All RCBOs are RCDs but not all RCDs are RCBOs.

 

[Chr!s]

Nooooooooooooooooooooooooooooooo. You cannot end it on such a flawed statement.


You must apply 415.2 unless the three conditions are met.

This is not an interpretation; that is what it says.



All RCBOs are RCDs but not all RCDs are RCBOs.

Geoff you are clearly very opinionated. Its pretty simple, 701 require SB to 415.2, it then modifys and supplements it with further requirement's.

1) it asks for Local, this isn't mentioned in 415.2, its supplementary.

2)it asks for the SB to be connected to the terminals of the protective conductors of equipment in the location and to be connected to extraneous parts either in the location or at entry.

Its pretty explicit and clear.

Now your touch voltage concept id flawed, it obeys ohms law, end of, there no debate to be had.

The original IEC uses Ut= If(max fault current) x Rbw(resistance of cable), its been adjusted to 50/Ia by BS7671 based on certain assumptions. Now using your method Ut(touch voltage) will be a product of (If), it may result in Ut be greater than 100 volts, even 150 volts

Now install a SB and we have a Current divider, assume little current flow in the SB in relation to R2 and we have a very low Ut(touch voltage).

Little knowledge can be dangerous, don't play with touch voltages unless you fully understand them, and to advise people SB is not required, well what can i say.

Chris

 

[jamie-spark]

Makes u wonder. If us qualified experienced electricians have different views. How does a Electrical Trainee think :-(

 

[D Skelton]

Makes u wonder. If us qualified experienced electricians have different views. How does a Electrical Trainee think :-(

They don't, the OSG gives them the wire-by-numbers diagrams that they need