To bond or not to bond

Trevor E: 
 

Hi,

Am spurring off a ring final to supply a 5A fused unit for operating a shower pump fitted to the water pipes in an airing cupboard. If my pipework is not continuous in metal then I need supplementary bonding between the pipes but if it is discontinuous then I may need equipotential bonding, can anyone please provide more of a steer on the latter point?

The question is a little confusing. The pump will automatically bond itself to any metal pipework via its C.P.C. 544.2.5.

701.415.2 may apply, but the pump is not actually in the bathroom or shower room. Supplementary protective equipotential bonding may be omitted under certain conditions.

30mA R.C.D. protection is essential though.

Z.

Thanks. knew it has cps protection but instructions talk about the need for supplementary bonding if the attached pipework doesn't earth separately through the incoming water main which obviously I can check but also says equipotential bonding may be required and that is the part I am unclear on 

Also meant to confirm that am spurring off a ring final which is 30ma RCD protected

If the pipes are not connected to earth by any means then they must not be bonded.

Parts only might require bonding because they are connected to earth at some point.

Your instructions appear to be incorrect.

but instructions talk about the need for supplementary bonding if the attached pipework doesn't earth separately through the incoming water main

It sounds like a muddled attempt to say that if you're cutting into pipes that form part of an existing supplementary bonding system (or are extraneous w.r.t. to the bathroom but rely on their connection to main bonding to allow actual supplementary bonding conductors to be omitted (under reg 701.415.2 (vi)) - then you need to maintain the continuity of the pipework across the pump. Such pumps often come with flexible connections or plastic pipe connectors which can spoil continuity even when copper pipes are used.

  - Andy.