Can anyone confirm this meets wiring regs please?...
I have rewired my house, and have ran a 4mm earth cable from kitchen sink to fuse board, 4mm from cloakroom sink to fuseboard, 4mm from bathroom taps to fuseboard, and 6mm form boiler to fuseboard. I have also used 10mm from gas supply to fuseboard.
Are these cable sizes ok (they are indepentantly wired, i.e. they do not loop into each other). Also is it ok to do it this way?
Not required. Actually a bad idea if the pipework is plastic.
Not required. Actually a bad idea if the pipework is plastic.
Not required.
You need to bond all the metal pipework and fittings and earth conductors of circuits in the bathroom together. This is normally done with 4mm cable, but you can use 2.5mm if it is protected from damage. This bonding doesn't need separately connecting back to the main earth terminal and must not be connected back to the main earth terminal instead of connecting to the earth conductors in the circuits locally.
Not required (over and above the earthing in the boiler supply).
However, you should earth the associated pipework unless it's plastic.
That's good. You need to do this with all metalic services into the house (e.g. water, oil) too.
Service bonding should be 10mm. Most of the other bonding you did wasn't required so there is no relevant cable size.
Er.. What is the thinking behind this? Assuming the gas supply to an external meter box is plastic and the consumer side is copper. Are we protecting the meter reader from shock or is there some other purpose?
Thanks for your reply, however i'm a bit more confused. How should I earth the kitchen and bathroom sink taps. Bond the hot and cold together then run one cable back to fuseboard? I have copper all round the house (only plastic, the blue MDPE pipe, from street). I'm just finding it hard to visualise the actual cable runs.
Kitchen taps don't need any bonding, as you've been told once already.
You don't appear to understand the basics of supplementary earth bonding, it's not about earthing everything, it's about keeping various zones at the same potential by connecting local pipework together, not to connect every bit of pipe in the whole house together. Maybe buy a book, or actually look into what you're doing
*before* starting a job, especially one where you can end up injuring people, by killing them.
On 18 Apr 2007 01:34:45 -0700 someone who may be mkkbb wrote this:-
To add to what the others have said. Copper pipe generally conducts electricity just as well, if not better, than copper cable, as it has a similar, or larger, cross sectional area compared to copper cable.
If there is reliable metal to metal contact along the length of a metal pipe then running a bit of copper covered in green and yellow plastic alongside it adds almost nothing to electrical safety.
Of far more importance is to bridge plastic inserts. For example a plastic water tank may mean some pipes are not earthed properly. This is easily solved by a few clamps and a short length of earth cable.
In rooms containing a bath and shower the aim is to ensure that all pipes and metalwork that may introduce a potential into the room are at the same potential. It doesn't particularly matter what this potential is, so long as there is not a difference between the potential of different pipes. That is what supplementary bonding is for.
This is explained well in the usual books on the subject, which may be borrowed from your local library before starting to do some work.
Although I've never looked into small pipe clamp sizes I have found that the cheap clamps are useless on most pipes. I tend to stick to the Tenby clamps as you don't have to tighten the screw up with a huge amount of force to tighten the strap up as you do with the cheap ones.
One thing not mentioned in terms of bonding is the bonding of the three pipes at the boiler. We had to do that with ours, and I guess it's a general requirement.
Well, I think it was, but that may have been in one of the other 56 bonding threads from this week. I will generally only bond all the pipes at a boiler if it's close to a bathroom or if the existing supplementary and\or equipotential bonding is a bit suspect.
There is no such rule that I am aware of. As long as the main equipotential bonding is done correctly along with the supplementary bonding in bath/shower rooms why would the boiler need x-bonding? A lot of plumbers ask for this to be done and say CORGI ask fot it doing, but many other CORGI plumbers do not ask for this doing.
On Wed, 18 Apr 2007 16:09:39 GMT someone who may be "ARWadsworth" wrote this:-
The flow and return pipes of heating systems are amongst those the relevant books indicate should be bonded, along with metal ductwork and a number of other things.
The reason I am interested is that a recent gas meter change for my Aunt was accompanied by a warning that the installation might not meet the regulations in respect of electrical bonding.
A local electrician has quoted for running 10mm earth cable from the service earth to the gas supply entry point. I have only heard my wife's version of the proposed route so may easily have misunderstood but, with continuous copper gas piping to the meter and plastic beyond: underground, I could not see any benefit to carrying the earth beyond the nearest convenient bonding point (at the boiler).
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