Looking on the TLC web site, there is text that states that an outdoor socket must be on a dedicated 30mA RCD. If this was fed from an existing kitchen ring, wouldn't there be a problem with discrimination between the local socket protection and the circuit protection at the CU? Is there an outdoor socket with integral RCD and can I back-to-back this through an external wall with a kitchen socket IYSWIM?
Any comments on height of sockets above worktops? Googling suggests that opinions are split either centering the sockets between worktop and underside of wall cupboards or specifically not centering or doing something that will marry with the tiles being used. As we aren't at tile choosing stage, I don't want to hold things up waiting for that decision. Similar with worktop thickness (still TBA), so approximate vertical centering is all that is really possible.
One group member has suggested that, if I don't move the cooker point, then I don't need to RCD it to bring it up to 17th edition spec. - any other comments from the floor? I am working on the assumption that the install will be inspected by BC appointed sparks, so these issues need to be correct and Part P compliant.
Where I have cables through a cavity wall, I understand that a pipe or conduit is required to protect these. What is recommended and is there a split version that I can fit retrospectively (rather than disconnecting and reconnecting exisiting equipment)?
I'm sure there were other points, but if I could remember them, the length of the post would probably scare off the regulars!
It needs to be 30mA - not sure it has to be dedicated. However...
There is a good case for not having outdoor sockets etc not sharing a RCD with inside ones. Since it increases the liklihood of getting nuisance trips on your house circuits.
There is no point in having cascaded RCDs though[1], since as you rightly suspect you can't predict whether one or both will trip, and if its one, then which.
[1] The exception being when the upstream one is a type S device with a time delay.
Roughly centre works for me, but go with whatever the management deems most desirable ;-)
If it don't line up with the tiles, then that's just an excuse to get a nice lekky tile cutter!
A bit more detail would help... i.e. what is there now, do you need it at all? Does it need moving etc.
Might be worth clarifying with BC what they are anticipating. Technically speaking a part P sparks can only do the work and self certify - they can't certify someone else's work. (However BC may be happy with a sparks just testing / inspecting and reporting on someone else's work - or they may even be happy with accepting your test results if they get the impression you know what you are doing).
Not necessarily. Cables should be either:
Buried >= 50mm from the surface, or Protected by an earthed screen of some form (i.e. earthshild, SWA, MICC, Steel conduit etc), or protected by a 30mA trip RCD.
Adding RCD protection is the easiest retrofit in most cases.
Do we look like the type to be scared by a few words ;-)
Where possible it is best practice to try and put the outside sockets on their own RCBO. If that is not possible then I try to power them via a double pole switch so that if they do let water in then they can be isolated without causing any problems.
There is no requirement for them to have their own dedicated RCD.
I still put them 6 inchs above the worktop unless otherwise instructed.
vbg.
I assumed that Phil was talking about passing a cable through a cavity for the outside socket! If so then use a bit of plastic pipe if you want to. Personally I just pass the cable through the hole.
Don't know - I've closed the link and can't re-trace it - but it did say that honest! (could have been an old link to be fair).
OK Good
Excellent - that covers many issues (one or two of which I needed reminding of)
Why is that then? Isn't this the place where it matters most? Metal sinks and stuff abound!
Good I think mine are OK then.
The cables pass through what was originally and external wall into the loft of my kitchen. So they go from a ceiling void in the main house to a loft space - not really a drill risk. I thought that some sort of conduit was expected, to stop the cable being hit by falling mortar or whatever in cavity - not that I think the place is falling apart you understand.
That I can see, but unfortunately I'm not in a position to route another dedicated feed through.
Yes I always ask the questions in advance, but it doesn't necessarly absolve me of responsibility unfortunately.
Hmm yes I have been pondering that idea!
Yes I need it exactly where it is now.
BC are supposed to inspect at first fix and then test on completion as part of the building notice AIUI - unless the goal posts have moved (again) of course.
Had intended fitting RCBOs to the affected circuits but they won't fit in my Clipsal box:(
On the strength of your previous posts I would say you were the most unlikely.
I think this subject has been covered off many times over the years, but the short version goes thusly: (someone correct me if I my memory fails me).
Supplementary bonding is only required (and then not always) in a location containing a bath or a shower, i.e. a space where a naked human being would get thoroughly wet.
When the regs (for supplementary bonding) first came out, they were either a bit wishy washy or all-encompassing (I forget which), so in a belt-and-braces, cover-your-arse kind of knee-jerk response, it became the done thing to supplementary bond every little piece of extraneous metal in any location with running water.
Many arguments ensued and eventually it became clear that the basic idea was to protect naked people in the bath or shower and everything else is an acceptable risk.
However, this idea of "bond everything to everything else and bond it back to the consumer unit, just to be on the safe side" became prevalent. And for many years people have complained that "the manufacturer didn't put an earth tag on the new kitchen sink, so what do I do with the earth wire I took off the old sink?" only to be told "cut it off you don't need it", which didn't go down too well, cos it sounded like a bodge.
Anyway, the full text of the above is as follows:
"5.2.3 Supplementary Bonding in Kitchens =======================================
There is no requirement in BS7671 to provide supplementary bonding in kitchens. Water pipes, metal sinks or draining boards do not require supplementary bonding."
===
The IEE "4.6 Additional Protection - Supplementary Bonding ==================================================
Supplementary bonding is required in some of the locations and installations of Part 7 of BS7671.
If the installation meets the requirements for earthing and bonding, there is no specific requirement in BS7671 for supplementary equipotential bonding of:
Kitchen pipes, sinks or draining boards.
Metallic boiler pipework
Metal furniture in kitchens
Metallic pipes to wash hand basins and WC's
Locations containing a bath or shower, providing the requirements of
701.415.2 are met[1].
Note: Metallic waste pipes in contact with Earth must be bonded to the main earthing terminal as they are extraneous-conductive-parts.
4.7 Supplementary bonding of plastic pipe installations. ========================================================
Supplementary bonding is not required to metallic parts supplied by plastic parts."
===
So there yo have it. :-)
Of course, you may still need main equipotential bonding in the kitchen, but that's another story...
Cheers, DaveyOz
===
[1] BS7671 17th Ed. Reg 701.415.2
" [...]
Where the location containing a bath or a shower is in a building with a protective equipotential bonding system in accordance with Reg
411.3.1.2, supplementary bonding may be omitted where all of the following conditions are met:
(i) All final circuits of the location comply with the requirements for automatic disconnection according to Reg 411.3.2 (ii) All final circuits for the location have additional protection by means of an RCD in accordance with Reg 701.411.3.3 (iii) All extraneous-conductive-parts of the location are effectively connected to the protective equipotential bonding according to Reg 411.3.1.2
Note: The effectiveness of the connection of extraneous-conductive-parts in the location to the main earthing terminal may be assessed, where necessary, by the application of Reg 415.2.2."
On Mon, 17 May 2010 17:35:27 +0100 someone who may be Dave Osborne wrote this:-
They were gold plated by some/many. It was always clear that if some metalwork could introduce a potential in a location then its resistance to earth should be measured and it should only be bonded if necessary.
I believe that the 15th edition started the idea to bond everything. The
16th edition certainly cleared the ground for what should be and not be supplementary bonded in one of its ammendments.
Well I know one regular poster to this newsgroup who always insists on bonding the metal socket back boxes to the socket fronts. I disagreed with him for a few years until he said "uk.d-i-y does better work than the pros and a good DIYer can afford to spend the few extra minutes doing the bonding".
It can be less than 30mA too. My outdoor socket circuit has a 10mA RCBO.
Include a double pole switch so you can isolate the outdoor circuit from indoors, in the event it gets wet and stops you keeping the indoor circuit on. You might also leave it switched off to stop someone else connecting appliances to it (which is why I have one even though it's a dedicated circuit). Actually, what works well for me is a cooker switch with integral socket in the garage, the cooker switch controlling the outdoor sockets (suitably relabeled).
That's entirely up to them. There's no requirement for them to test anything in Part P - that's just them gold plating the rules. It was originally envisaged that it would be a simple visual check by the BCO, not requiring specifically qualified electricians.
Just noticed - one "not" too many in that sentence!
If its just a waterproof socket on the outside wall and you already have RCD protection on the circuit, then I would not worry unduly. Like the others said, stick a double pole switch internally and you can isolate it should there be a problem.
Nope, even when just following instructions, its still going to be your fault! ;-)
Or better still, install one after the tiles are up - then you have an excuse for a multimaster.
So leave it alone and you will be ok...
Different LAs seem to have different ideas...
Is is a split load (i.e. could you just move the circuit to the protected side?)
I think the main issue to consider when setting the socket position is what size tiles you'll be using... if you get it wrong you can end up with just a sliver of tile at the edge of the socket, which looks really s**te. Same issue applies to the horizontal position of the sockets, although bad tile cuts are usually easier to circumvent then.
An option there is to chase the wall for the cables, but don't hack out all the back box space for each socket. You can then tile, and decide whether to align the sockets with the cable chase matching the top or bottom knock outs on the box. That gives you an inch of vertical shift to play with.
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