Finally got round to installing the cross-bonding in bathrooms etc....
Just to confirm that I'm still understanding the advice / regulations people here quoted to me last summer :-
In the bathroom I've just 'done' - have connected radiator, cold feed to lavatory, hot & cold bath taps, hot& cold sink taps all to the lighting earth in the bathroom. This constitutes 'all exposed metalwork'... should be OK ??
In the other bathroom (tomorrow's fun occupation !) I was proposing to connect the lav cold feed, basin taps, bath taps, shower mixer and radiator/towel rail. The main house earth block is just the other side of the wall, so I was planning to connect the green& yellow wire through to there.
I'm also very close to the airing cupboard, where I can bond to the water rising main, and, for good measure, the central heating pipework (worth doing ?)
Don't want to go mad with it - but want the surveyor who is due on Thursday to see a suitably impressive array of 'Safety earth' tags
The green&yellow stripey cable cost a fortune - apparently 'The Chinese are buying up all the copper' - so the man at the trade counter said ...??
Sounds OK. Note that you can use runs of soldered copper pipe as conductors. So for example if you connect hot to cold under the sink, you don't need an explicit wire to the bath tap location if it is soldered copper. Rad tails can be cross bonded under the floor so that you don't see unsightly clamps etc.
There is no requirement to take a separate earth connection back to the main earth terminal (although you will in effect end up doing this indirectly if you bond the CPCs of any circuits deploied in the bathroom).
Not really. There should already be your main equipotential bond to all the incoming services. The airing cupboard itself is not a "special location" and hence not considered to be an area of notable risk.
Chances are he won't know what they are for anyway! ;-)
The thicker sizes (10mm^2) used for main bonds can be pricey for a reel (i.e. over £50).
Are there any shaver sockets or extractor fans? If so are they supplied from circuits other than the lighting one? If so those circuits ought to have their CPC included.
Didn't know that... It's logical, but that doesn't always mean it's acceptable I'm afraid I was a bit of a lazy so-and-so when I was doing the installation - and some of the taps have flexy connectors - so in those cases I've fixed the bonding clamps direct to the threaded tap tails....
Ah well - done now !
Like a lot of this particular job, it'd be a lot simpler / neater if I'd done it when the floor was up and I'd not got the carpet / boxing in complete. Still - at least it's 'visible' now - makes it easy to inspect....
Sorry - CPC ? Please explain the term..... ? The main earth is just the other side of the wall - seems too got an opportunity to miss
The 'incoming services' thing is a bit of an odd one here. We have our own well, which feeds the loft storage tank via alkathene pipe - which only turns into copper in the airing cupboard. I guess I could bond that (the copper !) - but I'm not sure what it would achieve ??
The only other 'incoming service' is bottled gas, and getting a connection to that at the point of entry would be a right pain. I could bond it at the gas hob, though.... - that's near to the kitchen sink, which I could also include in the bonding. What do you think ??
Maybe not - but then I can tell him Way back when I used to work in Quality Assurance, we used to refer to the 'head them off at the pass' approach to being audited. The principle being that, if one could supply a snappy, credible answer to an auditor's question (regardless of whether it was actually true !) then that would normally suffice, and save the guy from 'digging deeper'....
This was a 100m reel of 4mm^2 green/yellow cable - which cost me topside of £35 + vat - apparently it was half that price a year ago (so the man said). Mind you - the bonding clamps were 20p each (in
20's) - whereas Focus wanted a wopping £1.55 EACH for the things !
Nope!
There is a shower pump and two blowers for the jacuzzi, but they're both earthed through the ring main. Guess I could hang a clamp on the just for good measure....
I'd rather err on the side of caution. It's taken us a long time to sell this house, and there's a brand new one waiting for us over in ireland. I really don't want 'anything' that a surveyor might see to delay things for us.....
Circuit Protective Conductor - i.e. the earth wire in the T&E cables for each of your circuits.
Yup see your point, but not needed.
The intention of the equipotential bonding in the bathroom is to ensure that anything you can touch can not be at a significantly different voltage to anything else you can touch - even in the event of a sever fault elsewhere in the house on in the supply to it. So you are not in effect worried what actual voltage all the metalwork is with respect to earth, what you care about is that it is all the same.
Ah, in which case OnSite guide section 4.3 would apply - which to paraphrase says if the incoming serices are plastic, but the pipework in the house metal then you still need main equipotential bonds to the pipework.
The significance will depend a bit on how your supply is delivered (mention of a well might indicate overheat wires and a local TT install)
(See
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a description of the different types of earthing)
If it is to be included (and I expect it should) then it ought to be bonded at the point of entry - or at least close to it before it branches anywhere. What else does the gas feed? or is it just the hob?
OK, but do it gently ;-)
There is also the rule about leaving a nice easy to find mistake for them to comment on so they go away happy they hace achieved something useful!
Yup, stuff like that can cost a fortune in DIY shops.
Note that for main equipotential bonds you will need either 6mm^2 (on TT) or 10mm^2 (TN-S or TN-C-S) wire and not the 4mm^2 you use for supplimentary bonds.
As long as you have included the CPC (i.e. earth wire) of the circuit feeding these in the bonding then there is no need for additional tags etc on them.
Ah, that sort of surveyor... chances are his only comment will be "wiring looked ok from what I could see, but you ought to commission a specialist report from some pricey outfit touting for work to be sure - don't take anything I say seriously" or words to that effect!
You cannot use normal earth clamps (BS951) below the floor boards as they are not available for inspection. You can solder the bonding cables to the pipes is you wish.
Depends on your definition of available. Lifting a floorboard would count as OK IMO, but getting under a tiled and ply covered floor would be a different matter.
In say a bathroom with bath, basin, toilet cistern, bidet, shower cubical where all the water plumbing is copper, would one set of clamps be permissible? I also have easy access to hot, cold and mains water pipes in the bathroom as they go their various ways via an airing cupboard (in the bathroom) which has the storage cylinder in it. That would be a very convenient place to fit the clamps.
Yes. One set of clamps (how many in a set?) will do for the hot and cold supplies with another pair for the flow and return for the radiator (and you could argue that they are already bonded to the hot and cold by the copper pipe work but inspectors like to see a bit of green and yellow cable). An airing cupboard in a bathroom that uses only copper is a perfect place to bond the bathroom. Piss easy to do the work, it is allowed the 16th edition regs and is easy to inspect. There are still the lighting circuits, electric shower, jacuzzi etc to bond where required.
Bonding of taps seems a little OTT. Either the pipes supplying the taps are copper and are x-bonded or the pipes are plastic and the taps would not then need bonding.
That is down to the installer of the bonding. Either use solder connections that are out of sight or bond using BS951 clamps in an adjacent room if possible.
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