Additional Earth Connection To Electric Shower

About 12 years ago when I installed my electric shower I did all the plumbing and cabling and got Scottish power ( It was SSEB then ) to do the final connection .The guy came and did the job but commented to add an additonal earth cable from the shower to the CH radiator and then back to the Scottish Power earth terminal beside the consumer unit . This I did and it has remained that way ever since .
I have just replaced my shower with a 10.5 one and was unable to get the circuit earth and this extra earth cable in to the cable connector ( The previous shower had a stud and nut connection arrangement ) so I have left out the additional earth between the earth and the radiator . It set me thinking why this extra earth was necessary in the first place and also about the earth from the radiator as well. Should I leave things as they were before ( Using thinner earth cable betweeen shower and radiator to allow it to get in to the connector) or what does anyone suggest ?
Stuart
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Stuart was thinking very hard :

The idea is to ensure that all metalwork is at the same electrical potential. All taps, baths, sinks, radiators, towel rails, metal pipes and etc. should be bonded to a common earth.
--

Regards,
Harry (M1BYT) (L)
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On Sat, 30 Dec 2006 20:23:06 GMT, Harry Bloomfield

Ok..so it seems you are saying I should return the arrangement to how it was before with the shower being connected to the radiator then to the Scottish Power earth point but there is the confusion caused by the part plastic ,part copper plumbing to the bath/basin /toilet .
Stuart .
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And all class I and II electrical equipment. No need to bond taps though. Although supplementary bonding will almost certainly result in the bonding cable been at earth voltage due to a light fitting, shower or a radiator etc there is no need to take the cable back to the earth busbar in the CU.
Generally the smallest bonding cable you can use is 4mm^2
Adam
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Stuart wrote:

The short answer is that it wasn't.

You need to ensure that the equipotential bonding in the room is present, however there is no need for a discrete connection back to the CUs main earth terminal (although since you would usually include the CPCs (i.e. earth wires) of any circuits delivering power into the bathroom in the equipotential bonding then you will in effect get this via a fortuitous route)
--
Cheers,

John.

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this may be of some help http://www.niceic.org.uk/downloads/Pocket%20Guide%202.pdf you need to connect all earth terminals in the zones together along with metal pipe work, metal bath and any radiator fed with metal pipes, dont run cable back to mains, this isnt about introducing earth potential but creating a faradays cage so all metal work will be at same potential. If your in England this is under part p of building regs and is a legal requirement to notify the local authority so is swapping a shower in a bathroom.....is your cable and pull switch up to the job (current) of the new shower?

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I am not in England .
The new shower pull switch and cable (10mm) are both suitable for the job .
All I was really wanting to know was about the instruction all those years ago to add in a seperate earth from shower to radiator to Sc Powers earth connection . The shower obviously has an earth connection via the supply cable so I couldn't see why an "extra" earth was necessary ( excluding the radiator as that's a seperate issue ). Thx for the link . I'll probably get a sparks in after the hols to check over the bonding as it's all Greeek to me despite having read about it and the use of part copper part plastic just confuses the issue . Stuart
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old regs
wrote:

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j* (aka -j ?) wrote:

There is no requirement to notify in the case of a replacement which does not involve altering the fixed wring or any protective switchgear.
--
Andy

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