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Earthing

Posted: Sun Mar 25, 2007 5:03 pm
by TH
I have just moved into a new house. Underneath the sink in the kitchen I have what looks like some earth wires that are not attached to anything. It appears that they may have removed their washing machine in a hurry.
I know that these wires used to have to be attached to something metal usually the pipework, but not sure that is the case with plastic pipework etc these days. Am I in danger what should I attach the wires too.
help please for a diy doughnut.

regards

Posted: Sun Mar 25, 2007 6:07 pm
by sparkydude
They are probably cross bonding cables which would be connected via an earth clamp to the copper hot and cold water pipes. if yours are plastic then these do not need to be connected to anything. A picture would be helpful if you can .

Nick

Posted: Mon Mar 26, 2007 10:31 am
by TH
attached pic of wires

Posted: Mon Mar 26, 2007 10:33 am
by TH
There is a plug socket just to left and the other end of wires look like they are attached to copper radiator pipes around the back.

Posted: Mon Mar 26, 2007 10:44 am
by ultimatehandyman
I have enlarged that picture and I think that the wires are both Green, is this correct?

They look like old bonding wires from the sink pipes, like sparkydude says!

There is no requirement to bond the kitchen pipes anymore, apart from the main bond from the incoming water main to the main earthing terminal.

Posted: Mon Mar 26, 2007 10:45 am
by sparkydude
Can you see where both ends of the cable go? you say one goes to the radiator pipe, does the other appear from the wall somewhere behind the sink . It looks like they need to be attached to your hot and cold copper pipes with the use of earth clamps.

Nick

Posted: Mon Mar 26, 2007 10:48 am
by sparkydude
Currently there is still a requirement to bond the pipes in a kitchen, but not the kitchen sink. All you have to make sure is that the cable is a continual loop between the hot, cold and radiator pipes.

Nick

Posted: Mon Mar 26, 2007 10:52 am
by Slugster
Sparky,

Can you go into a bit more detail about the bonding requirements?

Currently I've got the hot and cold and gas pipes all individually earthed back to the main earth block. This then goes to the earth spike and fuse box.

I've not got anything to the rad pipes. Do I need to bond every rad pipe or just the supply / return? Hoping it's just the supply because they are all one big lump of copper but best to check

Thanks

Posted: Mon Mar 26, 2007 11:09 am
by TH
They are both green and they both look to be attached to the radiator pipes

Posted: Mon Mar 26, 2007 11:34 am
by ultimatehandyman
As sparkydude says you can re-attach them to the hot and cold copper pipes- http://www.ultimatehandyman.co.uk/earth_clamp.htm

Posted: Mon Mar 26, 2007 11:41 am
by sparkydude
Basically the requirements for earthing in general in domestic properties are as follows:-

Main earth from suppliers facility to fuseboard or MET (main earth terminal) 10 or 16mm dependant upon main tails size

Main equipotential bond to gas,oil,water,structural steel and any other metallic incoming services 10mm to MET or fuseboard

cross bonding cable in airing cupboard or at combi boiler links all pipes at this point with earth clamps and cable 4mm

cross bonding cables at kitchen sinks 4mm and link hot and cold.

Cross bonding in bathrooms, to link , hot and cold, electric shower earth if fitted, metallic light fitting on ceiling, shaver point and radiator

all in one circuit of 4mm earth.

hope this helps slugster

Nick

Posted: Mon Mar 26, 2007 11:43 am
by sparkydude
As for your problem TH , as long as your bonding circuit covers hot ,cold and as yours is already done , the radiator then you have done what you need to do. There is no requirement to bond radiators in other parts of the house other than in a bathroom. As for why you have two earths coming from your radiator, its a mystery. If they come from the same pipe and earth clamp then perhaps they just had it so you had one earth cable in each earth clamp, on hot and cold.
any chance of a pic of the radiator connection ?


Nick

Posted: Mon Mar 26, 2007 11:48 am
by ultimatehandyman
sparkydude wrote:Currently there is still a requirement to bond the pipes in a kitchen, but not the kitchen sink. All you have to make sure is that the cable is a continual loop between the hot, cold and radiator pipes.

Nick
:?

I'm confused about this!

In my on site guide it says -

There is no specific requirement in BS 7671 to supplementary bond to the following-

Kitchen pipes, sinks or draining boards.

Metal furniture in Kitchens.

Metal pipes and wash hand basins in domestic locations other than bathrooms.

I don't want to appear to be one of those argumentative tossers that quote this reg and that reg :lol:

Posted: Mon Mar 26, 2007 11:55 am
by sparkydude
Well i know that in the new 17th edition they are removing the need to bond sinks and a certain amount of cross bonding. But i have always had it drummed into me that you cross bond pipes at kitchen sinks unless they have plastic supply pipes.

Nick

Posted: Mon Mar 26, 2007 12:01 pm
by ultimatehandyman
sparkydude wrote:Well i know that in the new 17th edition they are removing the need to bond sinks and a certain amount of cross bonding. But i have always had it drummed into me that you cross bond pipes at kitchen sinks unless they have plastic supply pipes.

Nick
I totally agree with what you are saying, I still bond kitchen pipes when I install a new kitchen :wink:

Do you know when the 17th edition is supposed to be coming out?