stupid question: switches for oven, fan, dishwasher etc

[David Robinson]

I'm sure I know the answer, but I can't quite believe it.

On Site Guide says that things like ovens, dishwashers, fridges, fans etc must have accessible isolation switches.

In our kitchen, each of these things (except the extractor fan!) will be connected to its own out-of-the-way socket. Original plan was to provide each socket with a 20A DP switch above the worktop, but most of them will _never_ be switched off. So I'm going to end up with all these switches above the worktops, spoiling the look of the place, and giving my little darlings the opportunity to switch off things that shouldn't be (like the fridge!).

The wiring (complete re-wire) will have to be inspected - is these anything I can do that will still "pass", but won't leave at least four unwanted switches visible?

The only one I actually _want_ is the fan - and that's already painful enough with a FCU isolator (hoping to put this above a wall cabinet), plus an accessible switch for manual override.

Cheers, David.

[Mr UPVC]

You can get modular switches which might allow you to fit all the switches in a double-width back box:

looks like MK do some kind of key-operated switch, which might be suitable for the fridge.

[1501]

Would it possible to place each DP switch concealed in a wall cupboard above the item? I had a (transformered) shaver socket in the bathroom that looked ugly but I was able to place the bathroom cabinet over it so it was accessible through the back. I had to fit a spacer between the hardboard cabinet back and the wall using extra long 3.5mm screws into the pattress.

[Dave Plowman (News)]

So is it saying a fridge plugged into an unswitched accessible socket is against regs? And does it define 'accessible'. In other parts a junction box under floorboards is 'accessible'.

[ARWadsworth]

Nothing wrong with using a socket as a means of isolation for fridges etc. Unswitched or double pole switched sockets are preferable.

Accessible? Have you seen the stuff my Mum has got shoved infront of her dishwasher socket at the back of the cupboard next to the dishwasher. I can lift floorboards faster than emptying that cupboard.

Electric hobs do need to have accessible switching for obvious reasons.

Cheers

Adam

[Dave Plowman (News)]

Right. It was the word 'switch' which I was concerned about.

I mounted mine as high as possible, reckoning I could just about squeeze an arm above the inevitable rubbish known as essential cleaning materials.

Given most might not be able to be on an approved plug and socket that's fair enough.

[Spamlet]

Our hob/oven one is accessible, though I never really know whether the switch is going to move before my thumb breaks! It actually gets a fair bit of use, because the Bosch oven insists on using a fan to cool itself down, instead of just turning off and cooling naturally: with no option to override this, we have to turn off at the wall after cooking anything.

S

[js.b1]

Electrician's Guide to Building Regulations...

- Built-in appliance = isolation switch above worktop

- Standalone appliance = isolation can be behind appliance

Cookers etc require separate treatment re dedicated supply.

So unless your appliances are built-in I would not be too concerned. An unswitched socket is a valid means of isolation - it forces the unplugging rather than mere turning off what could be a single pole switch on a socket (yes most are double pole these days).

[js.b1]

If you do go the grid backswitch route, some things to note...

Wiring multiple grid accessories is a bit fiddly. A large box is much easier to wire than slim, eg, for 2-3 switches use a 3-module 2G faceplate.

Grid backboxes are different. Flush grid backboxes have fixed mounting lugs - because the module mounting frames provide adjustability. Flush grid backboxes are meant to sit FLUSH with the finished surface so the module mounting frame fingers which overlap the edge of the box have a solid surface to sit against. If the box is not flush those frame fingers must be supported by tiles or plaster. The faceplate must sit flat on the mounting frame, otherwise the modules will not sit correctly underneath re flush & level.

This will be obvious when you play with Grid in your hand.

MK Grid is quite expensive - labelled switches are about =A35 and labelled switches with neon about =A36.50.

It can be useful to have a single central isolator - such as 32A 1G or

45A 2G isolator for all kitchen sockets. The 2m rule may apply depending on the appliances controlled. It gives a single point of isolation before you go for the fire blanket rather than fighting your way through a maze of grid switch labels.

A remote cooker hood switch can be handy if you have a midget and the hood & controls are mounted quite high (higher is better because the top-vents on many help to remove hot stagnant air by the ceiling). However personally I prefer a runback timer for cooker hoods - such as the Electrisave 15 (15/30/45min) or 30 (30/60/120min) which permit a defined cutoff period as well as ability to leave it running to get heat out after cooking (leave cooker/oven doors open, kitchen door shut).

[The Natural Philosopher]

The question is what constitutes 'built in'

[ARWadsworth]

When did you last have to unplug your fridge/freezer/dishwsher etc? I plugged my waching maching in 10 years ago and I unplugged it for the first time last week when I swapped it for a newer one (I am not going to say no to a free 12 month old washer).

And the fire risk. Although to be fair I now do a lot of insurance work and I have worked on more house fires caused by candles than cookers.

Cheers

Adam

[RobertL]

Do they each have to have their own individual switch or could you have one conveniently located switch that turns off the whole kitchen?

Robert

[js.b1]

Built In =3D Integrated Appliance.

[Andy Dingley]

Probably thanks even more to McD's replacing the domestic chip pan.

[Jim]

Even if it's otherwise allowable, I'd hate to try and make connections for 6x 2.5mm cables and the 2x 10mm ones for the oven in the same double back box.

[ARWadsworth]

Built In = Integrated Appliance.

I can see no reason why an integrated appliance needs an isolation switch above the worktop.

It only needs some sort of accessible switching. And that includes removing the contents of the cupboard next to the appliance to access the plug.

Cheers

Adam

[Toby]

Be careful with that - I think you will find the fan isn't to cool the oven down, but to stop the control electronics getting baked. Our Siemens (Bosh!) oven does this Does yours hoot air out the front, just under the control panel, that runs when the oven is on too? if so, that is what it's for...

Toby...

[1970alr]

Is that what it's for? Well it's a real noisy nuisance in many cookers. Whay can't they do it more quietly?

It's not as if it's something they advertise in advance: "by the way, this cooker makes so much noise that you'll feel that feeling of blessed relief when it stops half an hour into your meal".

Andrew

[js.b1]

Most are relatively quiet.

The "oven COOLING fan" is usually a very wide radial (cross-flow) blower and can be =A3120 a go, likewise the electronic control panel can be a similar amount. The "main OVEN fan" is a simple axial fan, typically =A312-19 and scream blue murder as they fail. I know I just did one and thus far all is fine.

Ah, do you find your oven cooling fan is emitting a "br-br-br" resonating like an diesel freight locomotive? If so then the rear access panel may be vibrating at a certain temperature re expansion & screw preload. You can tighten the screws slightly (they will strip if abused) or remove it, create a very slight twist and refit, anything to alter the frequency at which the panel exhibits sympathetic resonance with the oven / oven cooling fan.

Beware the amount of dust in fan ovens can be spectacular, I think I removed about 15lbs of dense heavy clouds of dust - it seems to "drip" off the "dust caked" oven cooling fan and down onto the oven cooling fan below. Dust isn't good re acting as a store for any oil or grease and ignition. Normally it is cooker hoods that cause fires, the motor stalls or overheats which lights off the grease/dust. Typical cooker hood AC motors do not cutout electronically, they have a crude bimetallic strip or thermal fuse or even nothing at all, when stalled current draw goes to maximum yet cooling is minimum so things get ugly. Cheap bathroom extractors also suffer from dust/overheating & fire/meltdown.

[John]

Strongly seconded - Really bad idea to switch it off at the mains. The fan is to stop the controls and electrics from overheating as the heat conducts out of the oven cavity. Mine will sometimes switch itself back on again for a while as more heat dissipates. It is doing what it is designed to do - and uses very little power.