First of all do I need to, I presume so ?
If I need to as I suspect, whats the best practise? Is it acceptable/best to cross bond the copper pipe back to the existing bonded pipework, or back to an earth connection at the back of a socket ?
As I understand it, everything in the bathroom needs to be bonded to everything else. In other words, the CPC (earth wire) terminal inside the shower is bonded to the cold pipe entering the shower, which is bonded to the bath and basin taps (hot and cold - yes cold again to account for dodgy joints or valves in the way) which are bonded to the metalwork of a metal bath which is bonded to any radiator and/or heating pipework which is bonded to the CPC in any shaver outlet (even though it is double insulated), which is bonded to the CPC in any fan and which may also need to be bonded to the CPC of the light and indeed
*anything* else metal which may be "earthy".The one thing which isn't neccessary is to run the bond back to the main earth terminal in / near the consumer unit!
HTH
Hwyl!
M.
But your pipe work must be bonded to earth from your main earth block as near to as possible where it enters your property and then cross bonded in bathroom and tested for continuity back to source.
The pump is in the airing cupboard upstairs. The hot pipe to the HWC is bonded, so should the other copper pipes?
Yes, the incoming water (and gas and oil) pipework must be bonded to the main earth, on the consumer's side, within 600mm (IIRC) of the meter or stop valve and before any branch pipework, but I can't recall any requirement to test that there is continuity between *supplementary* bonded metalwork in the bathroom and the main earth.
The point of supplementary bonding is *not* to make sure all metalwork stays at earth potential, rather it is to ensure that it all stays at the *same* potential, whatever that may be. The slightly dubious safety reasoning behind this is that if there is an earth fault in (say) your shower, this may cause the touchable metal parts of the unit ("exposed conductive parts") (not that modern showers have any) to rise above earth potential. By cross bonding these metal parts to other metal parts ("extraneous conductive parts" e.g. the taps) with which you may be in contact, in theory no current will flow (through you) as everything is at the same potential. Hopefully, of course, current
*will* be flowing down the CPC in the shower supply cable and will pretty rapidly switch off the supply.If you provide an explicit link from the supplementary bonding straight back to the main earth, this link could quite easily be of lower resistance than the CPCs involved (supp. bonding is usually in 4mm2 cable, CPCs of 6mm2 shower cables are 2.5mm2 and of lighting cables,
1mm2) and therefore anything thus bonded *could* be at a lower potential than the cause of the fault... and the fault current will flow through the bonding rather than the CPC which is where it should be flowing. Of course if everything is hunky-dory this is highly unlikely.Hwyl!
M.
Assuming that no one has at some time put plastic push fit connectors into the plumbing system . This would cause a fault current to find another way to earth other than via the bonded metalwork and or possibly the cpc. There may not be a requirment to test for continuity but it makes sense to when messing with power showers and water that was my point really.
On Tue, 02 Mar 2004 01:20:31 GMT, in uk.d-i-y Martin Angove strung together this:
But as you say, the point of the supplementary bonding is to make all the exposed metalwork in the bathroom the same potential. If this was linked to the main earth termminal then the metalwork would still be at the same potential, just lower. ..
SJW A.C.S. Ltd.
It is actually safer without any continuity to the main earthing terminal. It is just not normally possible to achieve.
The ideal situation is that all supplies are plastic and there are no electrics. Then you don't need supplementary bonding at all, even with metal baths and radiators.
Christian.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.