Internal drainage pipe help

[chris day]

If a cast iron internal drain pipe terminates outside into a clay drainage point is this still classed as extraneous conductive part.

I am being super careful as an NICEIC inspector had me box off a soil pipe on a PME system earlier last month and dont want to come a cropper again.

 

[Richard Burns]

The drain pipe being conductive and internal to the property then means that it would also have to be able to introduce an earth potential (or other potential) into the property to be considered an extraneous conductive part. Because the conductive part goes outside and connects to a non conductive part, so long as the internal drain pipe does not go out underground as usual, then this should not be an extraneous conductive part and in accordance with the 18th edition statements would not require bonding as there is an insulating part before it reaches the earth.
If the drain pipe exits the property underground and then joins on to a clay pipe then earth potential could be introduced and the resistance to earth should be tested to classify if it is an extraneous conductive part or not.

 

[chris day]

Thanks for the reply, the NICEIC had me box a similar item off last time.

 

[Wilko]

Perhaps that bonding pic might be useful. It shows a metal gas pipe exit the building but not needing bonding because it can't introduce a potential.

 

[FatAlan]

Does beg the question of how you would actually bond to a cast iron soil pipe? Not sure I would want to drill in to one and they are usually heavily painted or rusty on the outside.