I am intending using plasic pipe for the water feeds from the exisiting house to the new kitchen, existing house pipe is copper and already bonded to earth, will I need to put in a section of copper in the new install to bond to, and is 10mm sufficient for this bond, cable run for earth will be 10m.
many thanks once again, and apologies for the many questions, it's just that this group in VERY usefull at the moment (finishing extension off)
No.
any elaboration on the ambiguity of "no" :-)
You do not need to bond the plastic pipes.
John
Superb !! :-) just as well I havent bought the earth cable !! what about current flowing in the water to the taps in a fault condition though? just out of interest
Water isn't a good conductor. 0.5m of plastic pipe with water in it is regarded as good enough an insulator to prevent any risk of electrocution.
Conductivity of water is reckoned poor enough that a couple of meters of plastic pipe remove the earthing hazard. *In a bathroom*.
The OSG is quite specific about supplementary bonding requirements in kitchens: there aren't any, apart from earthed metal waste pipes, which are fairly unusual (4.6, p.24).
Just done some "googling" on the subject and it seems its safer not to earth if using plastic pipe. I take it the sink wont need to be bonded either?
Where is that current going to come from? The pipes are plastic, so bad electricity can't get into the water that way.
You do not need to bond plastic pipes, or even sections of copper pipe, in kitchens anyway. You do need to (a) main equipotential bond all metallic services where they enter the house[1], and (b) supplementary equipotential bond all metallic services where they enter a bathroom.
Owain
[1] i.e. equipotential bonding zone
Not strictly correct, the reference to bathroom, should ne expanded to ' rooms containing a bath or shower'
Steve Dawson
Is (b) the official line? If so it's confusing, because surely the idea is that all *exposed* metalwork in the bathroom is at the same potential?
Well, you don't need to bond metal taps fed by plastic pipe do you?
Owain
Not all exposed metalwork needs bonding in bathrooms.
I believe the correct definition of what needs supplementary bonding is "All exposed condutive parts" which is defined by the 16th edition as "a conductive part of equipment which can be touched and which is not a live part but which may become live under fault conditions".
A metal window frame for example whilst being exposed metalwork, should not be part of the supplementary bonding (it is very unlikely to become live due to it not using electricity) If a fault occured and such a window was supplementary bonded the window cleaner on the outside of the bathroom may get an electric shock.
Adam
Why would you need to bond taps that are fed by copper pipes if the copper pipes are correctly supplementary bonded?
Adam
I wouldn't.
Owain
No the sink should not be earthed (in fact the OSG explicitly says so IIRC).
(Note however you may meet inspectors who insist it should be, since it used to be included in the 15th edition of the regs AIUI, and is still cited in relativey recent copies of John Whitfields book).
Because the copper pipes may be joined with compression fittings which should not be relied on for electrical connectivity (soldered joints however are ok)
Strange how things change - this was precisely how MICC cables distributed their earth.
You have ignored the question. I asked about taps supplied by correctly bonded copper pipework.
Adam
Sorry, thought the answer was implicit.
If you have EQ bonded, soldered pipes, then you don't. However you may choose to install it anyway to allow for the possibility of changes later. If you have compression or pushfit fittings joining the pipes then equipotential bonding closer to the taps would be required.
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