Hi,
I have always understood from the regulations that a bonding conductor should be connected to any water installation pipes, gas installation pipes central heating etc, etc. Ok, it may be the case that these are not extraneous , but as i mentioned in an earlier post, things change over time; and yes it may be over the top, belt and braces and all that, but it is something I believe is necessary. Perhaps we don't all agree with that, but it does make life more exciting having these discussions, seeing we all interpret things in different ways.
Regards.
Regards.