Isolation Switches

[Barney12]

I was chatting to a kitchen designer yesterday who works for one of the "posh" kitchen suppliers and he was saying that they always design their kitchen electrics so that isolation switches for such things as; cookers, hobs and built in/under appliances are all in one location inside a cupboard. The idea being it reduces "wall clutter" above counter tops etc. Now to me that sounds like a fantastic idea but does it meet the regs? Would they be 'accessible' enough? He was very clear "that's how we always do it. Even on new builds. We just ensure each switch is clearly labelled".

[Ferdinand]

20 minutes ago, Barney12 said:

I was chatting to a kitchen designer yesterday who works for one of the "posh" kitchen suppliers and he was saying that they always design their kitchen electrics so that isolation switches for such things as; cookers, hobs and built in/under appliances are all in one location inside a cupboard. The idea being it reduces "wall clutter" above counter tops etc. Now to me that sounds like a fantastic idea but does it meet the regs? Would they be 'accessible' enough? He was very clear "that's how we always do it. Even on new builds. We just ensure each switch is clearly labelled".

 

That is interesting. I thought the 'high end' fashion was for grid switches in single housings above the worktop.

 

F

[Onoff]

No 'kin good whatsoever when you have to shift a stack of tins to isolate a "insert appliance here" in a hurry.....and you're in a wheelchair. These designers need a smack with a rolled up copy of the "regs" wrapped round a length of 25mm conduit! When you say regs we could be talking about BS7671 the "electrical regs" which aren't statutory but may be used as a defence in law (basically you're a ****if you don't follow them ) You've then got the statutory Building Regs, P & M for a start.

 

Back to the "bible" (afaic), 7671: On the assumption such switches may be needed for an emergency then in the back of a cupboard doesn't comply. Have a look in section 53 for a start. Says amongst other stuff that emergency switching shouldn't expose you to further danger etc. Well if your taking time to get to the tumble dryer switch etc when the things on fire and the kitchen's filling with smoke.....

 

Indeed it doesn't comply across the various statutory and non statutory guides.

 

A well designed, conveniently placed grid switch(es) with non switched plug tops to provide for mechanical maintenance is a good way to go IMHO. The grid no higher than 1200mm in a convenient wall space you're not going to keep brushing by. Need to carefully think out your cable runs, and of course it's more cabling.

 

Then if course there's the missus who just doesn't like grid switches.....which is why most of my stuff has a 20A DP switch above the worktop feeding an (accessible) unswitched plug top below

 

Edited February 10, 2017 by Nickfromwales

[Jeremy Harris]

5 hours ago, Barney12 said:

I was chatting to a kitchen designer yesterday who works for one of the "posh" kitchen suppliers and he was saying that they always design their kitchen electrics so that isolation switches for such things as; cookers, hobs and built in/under appliances are all in one location inside a cupboard. The idea being it reduces "wall clutter" above counter tops etc. Now to me that sounds like a fantastic idea but does it meet the regs? Would they be 'accessible' enough? He was very clear "that's how we always do it. Even on new builds. We just ensure each switch is clearly labelled".

 

More or less what I did.  I have one quickly accessible DP master switch on the wall, but all the individual circuits for the appliances are fed from a small bank of MCBs near the back on a side panel of a cupboard, mounted near the top to meet the accessibility requirements.

 

My preference was to be able to isolate the lot quickly with the master switch, if need be, whilst putting the individual circuit protection in an accessible area (as required by the regs) but normally out of sight.  In my case I have a 10mm² T&E feed to the isolator and then to the bank of MCBs, then appropriately rated cables to each appliance (IIRC all are on 2.5mm² T&E except the induction hob, which is on 4mm²)

Edited February 9, 2017 by JSHarris
typo - extra "i" crept in.....

[Barney12]

15 minutes ago, JSHarris said:

 

More or less what I did.  I have one quickly accessible DP master switch on the wall, but all the individual circuits for the appliances are fed from a small bank of MCBs near the back on a side panel of a cupboard, mounted near the top to meet the accessibility requirements.

 

My preference was to be able to isolate the lot quickly with the master switch, if need be, whilst putting the individual circuit protection in an accessible area (as required by the regs) but normally out of sight.  In my case I have a 10mm² T&E feed to the isolator and then to the bank of MCBs, then appropriately rated cables to each appliance (IIRC all are on 2.5mm² T&E except the induction hob, which is on 4mm²)

 

This idea of a single 'master' isolator followed by a bank of MCB's seems like an elegant solution. How does @Onoff feel about that idea?

[Jeremy Harris]

I should add that the feed to the kitchen wall isolator switch spur is from a 40A RCBO in the CU, so is adequately protected.

[Onoff]

1 hour ago, Barney12 said:

 

This idea of a single 'master' isolator followed by a bank of MCB's seems like an elegant solution. How does @Onoff feel about that idea?

 

So in effect a consumer unit with the DP isolator separated out.

 

And then what an MCB feeding its own appliance?

 

I prefer the visible grid. Each to their own.

 

 

 

 

 

[Jeremy Harris]

13 minutes ago, Onoff said:

 

So in effect a consumer unit with the DP isolator separated out.

 

And then what an MCB feeding its own appliance?

 

I prefer the visible grid. Each to their own.

 

 

 

 

 

 

 

Yes, but only because it suited our kitchen layout, plus, in part, it was a realisation late on (change of appliances, as a consequence of the ones we wanted having been superseded by new models)  that our original wiring plan wouldn't work.  It was the electrician who spotted the snag (we'd ordered two ovens that ran from a 13A outlets, but were delivered one that needed a 16A feed and one that had a 13A plug) and together we came up with the idea to fit the small bank of MCBs in the cupboard.  The original plan (in fact they are still there) was to run the ovens from 13A outlets at normal level on the wall adjacent to the tall double oven unit, as the two original ovens that I'd ordered both had 13A plugs fitted.

[Onoff]

I was looking for a photo of grid switch wiring but this was all i could find:

 

 

Much better is this sad bloke I found who takes photos of everything!

 

http://myhouseproject.me.uk/pages/electrics.htm

 

[Steptoe]

22 hours ago, JSHarris said:

 

 

Yes, but only because it suited our kitchen layout, plus, in part, it was a realisation late on (change of appliances, as a consequence of the ones we wanted having been superseded by new models)  that our original wiring plan wouldn't work.  It was the electrician who spotted the snag (we'd ordered two ovens that ran from a 13A outlets, but were delivered one that needed a 16A feed and one that had a 13A plug) and together we came up with the idea to fit the small bank of MCBs in the cupboard.  The original plan (in fact they are still there) was to run the ovens from 13A outlets at normal level on the wall adjacent to the tall double oven unit, as the two original ovens that I'd ordered both had 13A plugs fitted.

It may be of interest to some to note that, even though an oven may be fitted with a 13a plug, if it is rated at 2kw or more then it requires a dedicated circuit anyway, so if it had been wired correctly in the first place then the 13a socket could have been changed for a 20a DP switch and the breaker should have been a 16a anyway, so the problem would never have arisen if properly designed in the first place.

Edited February 10, 2017 by Nickfromwales
Autospell

[PeterW]

2 hours ago, Steptoe said:

....even though an oven may be fitted with a 13a plug, if it is rated at 2kw or more then it requires a dedicated circuit anyway, so if it had been wired correctly in the first place then the 13a socket could have been changed for a 20a DP switch and the breaker should have been a 16a anyway, so the problem would never have arise...

 

... and in doing so you will invalidate the product warranty. 

 

Appliances sold with a plug (and installed by the vendors too) can only be fitted using the plug supplied to comply with appliance  safety regulations in the U.K. This relates to the CE or safety marking as if an appliance is supplied with a moulded plug on its lead then to remove it and either replace it with a non moulded plug then invalidates the manufacturers warranty. 

 

So whilst partially correct in that as you say, a dedicated circuit is required up to the outlet, removing a manufacturers cord or plug is deemed to be a modification. The only allowance on this is if a manufacturer states in the installation documents that this is acceptable. 

 

A manufacturer would have no liability under SoGaS or Consumer law to fix or repair such an appliance as installed. There is case law on this somewhere and if I get time I will dig it out.

 

The reason I know this is because we dealt with a situation relating to this last year for a housing association and worked through it with a series of legal advisors. 

 

Suffice to say the manufacturer won ...!

 

[Onoff]

2 minutes ago, PeterW said:

 

... and in doing so you will invalidate the product warranty. 

 

Appliances sold with a plug (and installed by the vendors too) can only be fitted using the plug supplied to comply with appliance  safety regulations in the U.K. This relates to the CE or safety marking as if an appliance is supplied with a moulded plug on its lead then to remove it and either replace it with a non moulded plug then invalidates the manufacturers warranty. 

 

So whilst partially correct in that as you say, a dedicated circuit is required up to the outlet, removing a manufacturers cord or plug is deemed to be a modification. The only allowance on this is if a manufacturer states in the installation documents that this is acceptable. 

 

A manufacturer would have no liability under SoGaS or Consumer law to fix or repair such an appliance as installed. There is case law on this somewhere and if I get time I will dig it out.

 

The reason I know this is because we dealt with a situation relating to this last year for a housing association and worked through it with a series of legal advisors. 

 

Suffice to say the manufacturer won ...!

 

 

I don't think he was advocating removing the plug top per se,  just having a dedicated radial like you would for say an immersion. 

 

I'm sure he means 16A opd, 20A DP switch then unswitched socket thus keeping the plug top.

 

Don't forget he's foreign!

 

A non electrical manager asked the other day what DP stood for so we told him to Google it.....on the firms monitored intranet!

[Steptoe]

24 minutes ago, PeterW said:

 

... and in doing so you will invalidate the product warranty. 

 

Appliances sold with a plug (and installed by the vendors too) can only be fitted using the plug supplied to comply with appliance  safety regulations in the U.K. This relates to the CE or safety marking as if an appliance is supplied with a moulded plug on its lead then to remove it and either replace it with a non moulded plug then invalidates the manufacturers warranty. 

 

So whilst partially correct in that as you say, a dedicated circuit is required up to the outlet, removing a manufacturers cord or plug is deemed to be a modification. The only allowance on this is if a manufacturer states in the installation documents that this is acceptable. 

 

A manufacturer would have no liability under SoGaS or Consumer law to fix or repair such an appliance as installed. There is case law on this somewhere and if I get time I will dig it out.

 

The reason I know this is because we dealt with a situation relating to this last year for a housing association and worked through it with a series of legal advisors. 

 

Suffice to say the manufacturer won ...!

 

What I actually said,

The socket should have been wired as a radial in the first place,

then the oven could have been plugged into a correctly designed circuit.

I didn't advocate cutting the plug off anything,  as @Onoff said

Then when the 16a oven arrived the socket could simply have been changed to a 20a DP switch.

No need to cut any plugs off, and I doubt any domestic appliance is going to come with a 16a plug on it.

 

And yes, you are correct, MIs must always be followed, BS7671 actually has a statement to that effect.

 

[Barney12]

3 hours ago, Onoff said:

I was looking for a photo of grid switch wiring but this was all i could find:

 

What's the maximum load on a grid switch though. I'm guessing more powerful ovens and hobs can't be isolated via this sort of grid?

[Steptoe]

2 minutes ago, Barney12 said:

 

What's the maximum load on a grid switch though. I'm guessing more powerful ovens and hobs can't be isolated via this sort of grid?

Generally 20a

But you can get larger, but it's going to take up more ways, and not really practical,

I'd have to check if a contactor could be used for isolation, but I doubt it.

[Onoff]

You'll be able to get a dedicated cooker control switch that matches the grid finish. Put it separate to the grid imo. Anyway, don't forget anyway the switch needs to be within 2m of the cooking appliance. If you use the one switch to control two appliances neither should be more than two metres away.

 

You can feed 2 or more cooking appliances via a single circuit >15A / <50A but they need to be in the same room.

 

EDIT: I would implore anyone embarking on such work to buy a copy of the IET guide to the building regs. Full of info.

 

http://electrical.theiet.org/books/amendment-no3/egbr-4ed.cfm

Edited February 9, 2017 by Onoff

[Jeremy Harris]

1 hour ago, PeterW said:

 

... and in doing so you will invalidate the product warranty. 

 

Appliances sold with a plug (and installed by the vendors too) can only be fitted using the plug supplied to comply with appliance  safety regulations in the U.K. This relates to the CE or safety marking as if an appliance is supplied with a moulded plug on its lead then to remove it and either replace it with a non moulded plug then invalidates the manufacturers warranty. 

 

So whilst partially correct in that as you say, a dedicated circuit is required up to the outlet, removing a manufacturers cord or plug is deemed to be a modification. The only allowance on this is if a manufacturer states in the installation documents that this is acceptable. 

 

A manufacturer would have no liability under SoGaS or Consumer law to fix or repair such an appliance as installed. There is case law on this somewhere and if I get time I will dig it out.

 

The reason I know this is because we dealt with a situation relating to this last year for a housing association and worked through it with a series of legal advisors. 

 

Suffice to say the manufacturer won ...!

 

 

FWIW, as assumptions are being made here that may well be well off the mark, and not for the first time, we fitted the kitchen wiring, plastered the house out, painted the walls, fitted the floors and kitchen and THEN ordered the appliances. There was a proper and fully worked through design for the kitchen appliance wiring, signed off by our electrician post installation of the wiring points for all the appliances that we had PLANNED to install.

 

In the delay between selecting the kitchen appliances and ordering them, the manufacturer discontinued the line of ovens we (well, SWMBO), had originally selected.  The supplier tried their best to get the versions we had originally wanted, but there were none available.  We selected the recommended replacement from the manufacturer, same size, same sort of style, same functions, and the supplier agreed to sell them at the same price as the previous models, out of goodwill, BUT, the main oven spec had changed and it had been increased in power and so was now supplied without a lead and moulded 13A plug, as the rating had increased to 16A.   Worth bearing in mind, as an aside, that the maximum continuous rating of a properly manufactured BS1363 plug is not 13A, it's 10A, which is why plug in car chargers that come with electric cars are only rated to charge at 10A. 

 

The consequence for us was that the electrician was called back to advise and change the installation, and the best compromise was reached, one that didn't require the walls to be ripped apart to get at the original wiring (well, not strictly true, a section of plasterboard had to be cut out to run the new cables, but luckily just a slot that could be patched and redecorated).

 

Just one of those things that happen with a self build.  Sometimes you can't plan for a manufacturer changing the design of a product in the time between planning first fix and fitting the kitchen.  Not bad planning, not a human failing, not an error, just bad luck that had to be worked around.  Between us, the electrician and I came up with a compliant solution, using what was already available, whilst causing the least disruption to the newly fitted and decorated kitchen.

 

 

 

Edited February 9, 2017 by JSHarris
typo, "can" when I meant "came" - sorry for all the typos, I make them all the time............

[Jeremy Harris]

1 hour ago, Onoff said:

 

A non electrical manager asked the other day what DP stood for so we told him to Google it.....on the firms monitored intranet!

 

Classic!  Did anyone tip the IT people off to check the logs and see what he was looking at on the web as well?

[PeterW]

48 minutes ago, Steptoe said:

What I actually said,

The socket should have been wired as a radial in the first place,

then the oven could have been plugged into a correctly designed circuit.

I didn't advocate cutting the plug off anything,  as @Onoff said

Then when the 16a oven arrived the socket could simply have been changed to a 20a DP switch.

No need to cut any plugs off, and I doubt any domestic appliance is going to come with a 16a plug on it.

 

And yes, you are correct, MIs must always be followed, BS7671 actually has a statement to that effect.

 

 

I stand corrected ..! What I thought you had said was to cut the plug off the 13a and wire it into a 20a DP - now see what you meant. 

[Steptoe]

5 minutes ago, PeterW said:

 

I stand corrected ..! What I thought you had said was to cut the plug off the 13a and wire it into a 20a DP - now see what you meant. 

It's fine ,

@Onoff knows how I say things by now, I only learnt 'proper' English at  school when I turned 11 and sometimes find it hard to convey in writing what I'm actually thinking.

[Onoff]

11 minutes ago, Steptoe said:

It's fine ,

@Onoff knows how I say things by now, I only learnt 'proper' English at  school when I turned 11 and sometimes find it hard to convey in writing what I'm actually thinking.

 

Helps that my Mum's from Stab City! Still says "lurry" for lorry.

[ProDave]

I am still not quite understanding what last minute changes the electrician had to make due to the change of oven spec. If it had been wired from the start with a dedicated radial for each oven, and one changed from 13A to 16A then all that needed changing was to replace the unswitched 13A socket behind the oven to a CCU to hard wire the 16A one, and perhaps change a 13A switched FCU on the wall to a 20A DP switch.

 

There is more to this than I am understanding......
 

[Jeremy Harris]

34 minutes ago, ProDave said:

I am still not quite understanding what last minute changes the electrician had to make due to the change of oven spec. If it had been wired from the start with a dedicated radial for each oven, and one changed from 13A to 16A then all that needed changing was to replace the unswitched 13A socket behind the oven to a CCU to hard wire the 16A one, and perhaps change a 13A switched FCU on the wall to a 20A DP switch.

 

There is more to this than I am understanding......
 

 

Two 13A single gang sockets were fitted next to the oven unit (wired as spurs of 2.5mm T&E), on the wall, to take the 13A plugs from the two ovens.  When the 16A oven arrived, the MIs said that it should not be wired with flex, and the terminals were clearly designed not to easily take flex.  That meant we couldn't just replace one of the 13A outlets with a 20A DP switch easily (sorry, I don't have a photo, but it would have looked pretty dire).

 

Had the new oven been OK with flex, then I'd have suggested just fitting a 20A DP switched outlet, but as above, it wouldn't have looked good.

 

What we have now looks a lot neater, and will be neater still when I've put some plasterboard into the holes where the old outlets were and made good.  It also means no holes in the side of the tall oven unit to run the two cables, which was the original plan.  The original idea was to fit the side trim panel to the tall oven unit after feeding the oven plugs through holes in the inner cabinet, so there would be just two slots for the cables at the wall side.  The spur wiring to those two outlets was removed when we cut the hole in the wall to run the new cable in - luckily it was only short and we could pull them out of the clips (with a fair bit of effort because of the awkward corner I was working in).

 

All told it was a lot of faffing about, at least a day of my time trying to do the minimum amount of damage whilst pulling out old cables and putting in new, then making good the slot in the plasterboard, and half a day of electricians time in wiring it all up and testing it again.  I felt like a gynaecologist at times, trying to get cables through spaces where I couldn't see where they were going, where the only access was via a hole right at the rear top corner of a kitchen cabinet......................

Edited February 9, 2017 by JSHarris
more typos...........

[Steptoe]

10 hours ago, JSHarris said:

 

Two 13A single gang sockets were fitted next to the oven unit (wired as spurs of 2.5mm T&E), on the wall, to take the 13A plugs from the two ovens.  When the 16A oven arrived, the MIs said that it should not be wired with flex, and the terminals were clearly designed not to easily take flex.  That meant we couldn't just replace one of the 13A outlets with a 20A DP switch easily (sorry, I don't have a photo, but it would have looked pretty dire).

 

Had the new oven been OK with flex, then I'd have suggested just fitting a 20A DP switched outlet, but as above, it wouldn't have looked good.

 

What we have now looks a lot neater, and will be neater still when I've put some plasterboard into the holes where the old outlets were and made good.  It also means no holes in the side of the tall oven unit to run the two cables, which was the original plan.  The original idea was to fit the side trim panel to the tall oven unit after feeding the oven plugs through holes in the inner cabinet, so there would be just two slots for the cables at the wall side.  The spur wiring to those two outlets was removed when we cut the hole in the wall to run the new cable in - luckily it was only short and we could pull them out of the clips (with a fair bit of effort because of the awkward corner I was working in).

 

All told it was a lot of faffing about, at least a day of my time trying to do the minimum amount of damage whilst pulling out old cables and putting in new, then making good the slot in the plasterboard, and half a day of electricians time in wiring it all up and testing it again.  I felt like  gynaecologist at times, trying to get cables through spaces where I couldn't see where they were going, where the only access was via a hole right at the rear top corner of a kitchen cabinet......................

That makes it a lot clearer. 

But it seems it was never designed correctly in the first place.

And I've yet to see any form of terminal that has been designed to NOT accept flex, ferrules are made for a reason.

It would be interesting to know what sort of HR (heat resistant) cable was specified,,,,,,

 

Edited February 10, 2017 by Nickfromwales
Unnecessary text removed

[SteamyTea]

Thanks for the tip about Googling DP, I may be gone some time