earth bonding

11 Dec 2004
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United Kingdom
im cross bonding my water and radiator pipes in 4mm earth cable BUT
(1) what size earth cable should be used from the main earth block to the earth terminal in the consumer unit,at the moment there is 6mm cable,but should 10mm or 16mm be used.

(2) what size earth cable should be used from from the main earth block to the main incoming water/gas/electric pipes 6mm or 10mm,at the moment this to is run in 6mm.

(3) what factor determines what cable size should be used,does the difference in cable size make any significant changes?

(4)do i need to cross bond my gas to water pipes on the boiler,im getting a headache thinking about it! :confused:
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1) Depends on Installation, but use 16mm

2) Current Regs 10mm

3) Its dependant on the regs the installation was installed to.

4) I would cross bond every pipe under the boiler, just to be sure. I use 10mm for this as I normally have plenty :D

35mm sq or less (size of meter tails)...................10mm sq (equipotential bonding conductor)

over 35mm sq up to 50mm sq........................16mm sq

This is only a guide as it will depend on the installation.
A good buy is On-site guide (Brown Cover) £15.
Hope this helps

im pretty sure its size of incoming supply neutral not meter tails and it only applies to PME its 10mm for most domestic sizes of PME supply but many recs recommend 16mm

for TN-S you should not need more than 10mm exept perhaps on an extremly huge install
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What about your immersion heater cylinder/pipework?

especially if it is situated within the bathroom area?

thanks to all for the tips,now i know what size cable goes where no more headaches.
just to let kai know i havnt got an emersion heater cylinder as i took it out when i got the boiler installed

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