Purely hypothetical because of Regulation P etc and the need for work to be carried out by competent persons etc etc but I would welcome advice on the following
I need to install a switched fused spur for a dishwasher and I would like clarification about how to do it.
Am I correct in thinking that this spur acts purely as a fused switch between the ring mains and the socket for the dishwasher?
Can I simply pick up my connections for the fused spur from an existing double socket which is on the ring main and then connect a 13 amp socket to the fused spur?
Is it connected as follows : Ring main socket --- fused spur ---- 13 amp socket for dishwasher
Does the spur have to be mounted above the worktop?
Yes. Strictly speaking there is no reason why you have to use a fused spur. A 20 amp double pole switch would also be acceptable if you are using 2.5 T&E on a conventional final ring circuit.
Yes, but ring mains are supposed be be "balanced" so that heating appliances such as washing machines and dishwashers are not too near one end of the ring. I have yet to see an electrician attempt to do this.
No, but it needs to be accessible without removing the appliance.
You do not have to have a switch at all if the socket that powers the appliance is accessible without removing the appliance. One common way of doing this is to have the socket in a cupboard next to the appliance.
That faq says correctly "The socket should be the un-switched variety, with a separate isolation switch fitted above the worktop in a convenient position. " note the switch is still required it is refering to the socket outlet only.
It is required for fixed appliances ie built in/under the disconnection of the earth is not permitted the means of isolation must break both poles only with a minimum contact gap of 3mm, a 13amp plugtop is for portable equipment, you would not plug an immersion heater in for example.
That's covered in the previous paragraph by suggesting it goes in an adjacent cupboard (which is what I do with all mine). I don't believe there is any regulatory requirement to isolate the machine before moving it, although it's easy to arrange by appropriate positioning of the socket, which I would strongly recommend.
It's not a requirement. Switching off a failed machine which may start exploding when you pull it out of it's recess is known as emergency switching, not isolating, and there is no requirement for emergency switching in this situation.
Yes. It's a convenient place for sockets for any appliances either side of the sink, providing the accessories are designed for that environment as I said above.
Sure. I think it's better to design the wiring layout so the plug and socket are accessible and are used for isolating. (Any separate isolating switch must be double pole.)
5 (1) The majority of the regulations are directed at hardware requirements. Installations are required to be of proper construction; conductors must be insulated or other precautions taken; there must be means of cutting off the power and means for electrical isolation. The hardware requirements are complemented by a group of regulations stating principles of safe working practice. Regulation 14, which covers live working, is of particular importance.
INTERPRETATION (Reg 2)
7 (1) The definitions of danger and injury are linked but distinguished to accommodate those circumstances when persons must work on or so near live equipment that there is a risk of injury, ie where danger is present and cannot be prevented.
(2) Danger includes danger to the public.
(3) The definition of electrical equipment excludes items which only generate electricity adventitiously, eg as static.
(4) Earthing and isolation are defined in regs.8 and 12 respectively.
Precautions for work on equipment made dead 13. Adequate precautions shall be taken to prevent electrical equipment, which has been made dead in order to prevent danger while work is carried out on or near that equipment, from becoming electrically charged during that work if danger may thereby arise.
incorrect Work on or near live equipment 14. No person shall be engaged in any work activity on or so near any live equipment (other than one suitably covered with insulating material so as to prevent danger) that danger may arise unless- (a) it is unreasonable in all the circumstances for it to be dead; and (b) it is reasonable in all the circumstances for him to be at work on or near it while it is live; and (c) suitable precautions (including where necessary the provision of suitable protective equipment) are taken to prevent injury.
Andrew, the socket location as described is not accessible. You seem to be assuming it can be reached and switched off by opening the adjacent cupboard door. This is not the case with mine, and I believe generally with today's cupboards, because they have a back panel with a dead space some 100mm deep between panel and wall. The socket is mounted on the wall in that space and accessed via a cutout in the side panel once the machine is pulled out. The machine's 13A plug/cable is threaded through this hole before pushing the machine into place. Since the socket then becomes inaccessible to isolate the machine it is pointless fitting a switched socket, hence the advice to fit a separate isolation switch above the worktop.
The diagram below outlines this.
[Turn on fixed pitch font to view diagram]
---------------------------------------------------- ________________ Worktop /| SINK / / |_____________ / /_/______________/ --------------------------------------------- | | | | /| | | / | I don't believe there is any regulatory requirement to isolate
As above, I don't see any way that a switched socket can do this with modern fitted units. A switched socket above the worktop would mean a trailing cable over the worktop - I'm sure that is not what you mean, so I'm puzzled as to where you consider 'appropriate'.
OK, but this FAQ is not trying to teach the reader 'the regs', but advising good practice for a convenient installation (which must comply with regs). Because something is 'not a requirement' is not a reason in itself not to do it!
A footnote to refer to the appropriate regs would be a useful addition.
I'm not clear if you mean it is OK to site outlets right under the sink where there is likely to be water. If you mean 'yes, provided they can stand getting wet', I'll take that to be a 'no' for practical DIY installations. Thinking about advice to DIYers, it seems more useful to simply say 'don't fit outlets under the sink'.
How?
Noted. It also might be worth referring to a specific example e.g. "MK K5423 20 Amp DP Plateswitch with Flex Outlet and Neon"
Cut a suitable access hole through the panel (that's what it already says in the FAQ).
Sorry, looks like there is some confusion here -- maybe I wasn't clear enough. I didn't suggest a switched socket. The plug and socket alone is the isolator (BS7671 537-02-10). A switched socket is actually a bad choice, as the integral switch might be used as an isolator, when it might not be a
2-pole switch (which is why CORGI don't allow boilers to be plugged in to switched socket outlets). (Yes, I know DP switched sockets are available, but you can't tell by looking at them, nor is there any assurance someone would replace one with another one.)
Well, that's up to you. Products are designed for this purpose.
As above -- just install an unswitched socket which is accessible from an adjacent cupboard. This also enables you to pull the cord clear of the appliance wheels/feet as it is pushed back in to position.
Just a plain 20A DP switch. The cable outlet is no use (although it's an optional knock-out anyway, and they don't do one without), and I personally wouldn't have a neon on something which is expected to be switched on all the time. MK K5403 is the same without the neon.
I have also seen examples where a FCU above the worktop feeds a flex outlet plate behind the washing machine etc that allows the appliance to move further back under the worktop than if a socket was used.
I think the current trend on new builds to have switches for all appliances above the worktop spoils the appearance of the splashback/tiled area and I prefer to avoid doing so if a convenient place can be found elsewhere for the supply. In particular I hate to see it on fridge freezers when children may switch it off and defrost the contents.
OK, I accept that a hole in the back panel is an alternative way of accessing it, and permits the omission of a separate isolator switch. I still prefer the above worktop isolator though, for convenience (e.g to switch of when going on holiday), and 'obviousness'. A repairman for a future owner of the house may well pull out the machine before realising that there is an access panel concealed in the back of the cupboard, or the owner may just forget.
Yes, I didn't realise you had a hole in the back panel.
Agreed.
Definitely.
Unplugging is preferable to isolating by a DP switch AND unplugging?? I don't see how, not that it really matters.
True, but I achieve the same by tying a string to the cord, and pass this up over the top of the machine to the front. Use this to keep the surplus cord off the floor as you push the machine back in.
Agree about the neon. I spent some time looking for one without the flex outlet, and as you say there is not one. You just wire the T+E to the flex terminals - no real problem - but it would help if they said so in the spec.
Hmmmm... looks as though that FAQ section needs extending with some options.
Would that be a Switched and Fused Connection Unit (SFCU)?
Food for thought here. Perhaps it IS better to provide isolation by just unplugging from a concealed but accessible socket, as per Andrew's scheme. I must confess that in my kitchen the many socket outlets and switches do rather dominate the tiling over the work area. This is something to think about when deciding which way to do it. What do others think?
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