Switches near hobs

[JohnW2]

Thanks. Yes, it does. I think it's 6A - it's a wylex MCB, and it says: B6 NHXB06

Fair enough - at least that's OK for a 1mm cable!

Rather amazingly, I have four circuits in my kitchen (ignoring the downstairs lighting circuit). The ratings, and the cable sizes (taken from the installation certificate) are:
- 40A cooker (6mm)
- 32A kitchen ring (2.5mm)
- 6A circuit for a single pull-cord switch in the larder (this was supposed to be the "induction hob" circuit.) (1mm)
- 6A circuit for a tiny little extractor fan (1mm)
I can understand the dedicated circuit for the larder light (I asked for this, so I could put in an induction hob). I cannot for the life of me work out why there is a dedicated circuit for the extractor fan, but never mind.

From what you now say, it sounds as if that 1mm² circuit was for a 'larder light', not for the induction hob itself. If it is intended as a lighting circuit, 1mm² is fine for that - do you still want/need this 'larder light'? As has been said, as for the extractor fan circuit, it is strictly non-compliant with the regulations to use 1mm² cable for anything other than lighting - maybe the electrician reckoned that an extractor fan counted as that, given that such fans are usually fed from lighting circuits! He was obviously confident enough to actually document it as being wired with 1mm² cable!

Kind Regards, John

 

[DavidA1982]

What plinth heater do you have model and output, is this purely electrical or if you have not yet purchased one, is it possible to have one connected to the central heating, then you will only need electrics to power the fan.

Thanks. It's purely electrical - too late now to try to get one connected to the central heating! If I can put the switch/FCU for it inside the cupboard as has been suggested above, it won't be a big issue to extend the kitchen ring to accommodate it. I'll ask the electrician what he thinks. Getting power to it is easy - finding a place to put the switch is the hard part!

 

[PrenticeBoyofDerry]

Can you not put the FCU next to the socket you take the feed from?

 

[DavidA1982]

Thanks. Yes, it does. I think it's 6A - it's a wylex MCB, and it says: B6 NHXB06

Fair enough - at least that's OK for a 1mm cable!

Rather amazingly, I have four circuits in my kitchen (ignoring the downstairs lighting circuit). The ratings, and the cable sizes (taken from the installation certificate) are:
- 40A cooker (6mm)
- 32A kitchen ring (2.5mm)
- 6A circuit for a single pull-cord switch in the larder (this was supposed to be the "induction hob" circuit.) (1mm)
- 6A circuit for a tiny little extractor fan (1mm)
I can understand the dedicated circuit for the larder light (I asked for this, so I could put in an induction hob). I cannot for the life of me work out why there is a dedicated circuit for the extractor fan, but never mind.

From what you now say, it sounds as if that 1mm² circuit was for a 'larder light', not for the induction hob itself. If it is intended as a lighting circuit, 1mm² is fine for that - do you still want/need this 'larder light'? As has been said, as for the extractor fan circuit, it is strictly non-compliant with the regulations to use 1mm² cable for anything other than lighting - maybe the electrician reckoned that an extractor fan counted as that, given that such fans are usually fed from lighting circuits! He was obviously confident enough to actually document it as being wired with 1mm² cable!

Kind Regards, John

That is exactly what has happened. The old installation had a dedicated circuit for a larder light (at the time, there was a separate, room for the larder - we knocked it through to create a bigger kitchen). When the electrician came to do my rewire, we agreed to leave the kitchen as it was (he tested it first), but I did say that I wanted him to put in a proper cooker circuit as the previous owners had simply put a plug on their cooker flex and plugged it in to a socket (!). I also said that I wanted a separate circuit for an induction hob for when the time came. He said he would replace the circuit for the larder light with something suitable - it looks like he didn't. The separate circuit for the extractor fan is a mystery! In any case that extractor fan is long-gone. The new one is fed from the kitchen ring. I do not want or need either of the 6A 1mm circuits. There is no longer a larder to be lit; and the new extractor fan is on the kitchen ring.

For what it's worth, my smoke detectors are also on a 1mm circuit.

 

[JohnW2]

Can you not put the FCU next to the socket you take the feed from?

If I understand correctly, the OP wishes to use the FCU as the function switch for the plinth heater - so it's possible that next to the socket it's fed from may not be very convenient for him.

Kind Regards, John

 

[DavidA1982]

Can you not put the FCU next to the socket you take the feed from?

There are not any sockets on that side of the kitchen. I've got a sink, a bit of space, a hob, and some tall units. Perhaps not the best design in the world, but I've got limited space and a lot of stuff to store and I don't envisage preparing any food on that side of the kitchen.... which is why I started this thread, really!

 

[DavidA1982]

Can you not put the FCU next to the socket you take the feed from?

If I understand correctly, the OP wishes to use the FCU as the function switch for the plinth heater - so it's possible that next to the socket it's fed from may not be very convenient for him.

Kind Regards, John

Correct, thanks.

 

[PrenticeBoyofDerry]

We both said that 6mm² on a 32A MCB would almost certainly be OK for the total cooking load indicated by the OP (in fact, I wrote that before you did).

Not after any brownie points, but really?
I think it was me that first questioned cable size and loading of the cooking appliances and informed the OP regarding rule of thumb 32A/15kW, then 6.00mm cable.
I maybe wrong but I do not recall this being mentioned prior to me putting my two penneths worth in!

 

[JohnW2]

Not after any brownie points, but really?

Hey, none of this is about brownie points, certainly not as far as I am concerned, but ....

I think it was me that first questioned cable size and loading of the cooking appliances and informed the OP regarding rule of thumb 32A/15kW, then 6.00mm cable.

It was, and that definitely gets you some brownie points.

I maybe wrong but I do not recall this being mentioned prior to me putting my two penneths worth in!

It hadn't been previously mentioned, but your comment/question was at a time when we didn't yet know the power requirement of the OPs oven. When he did tell us...

The oven says 4.4kw on the side - does that help?

Indeed. That plus your 6.8kW induction hob would easily be both supplied by the 6mm² 32A cooker circuit you have.

The oven says 4.4kw on the side - does that help?

That would give a maximum output of 11.2kw, a diversity calculation can be factored in, which would mean if an isolator without socket-outlet was fitted then the you are looking less than 22A current which a 6.00mm T&E cable will safely carry providing there are no de-rating factors to consider such as cable routes within containments such as trunking/conduit and the cable is not within thermal insulation along parts of it's route.

I’ll leave you to do any allocation of brownie points there In fact, we are now told that it is a 40A MCB, not a 32A one, so I was making an incorrect assumption.

I’m about to open a bottle, and would suggest you join me on this Saturday evening!

Cheers, John

 

[PrenticeBoyofDerry]

I’m about to open a bottle, and would suggest you join me on this Saturday evening!
Cheers, John

Already started, getting togs on!

Untitled

• PrenticeBoyofDerry
• 18 Apr 2015
• 1

Clink!

 

[JohnW2]

Already started, getting togs on!

Untitled

• PrenticeBoyofDerry
• 18 Apr 2015
• 1

Clink!

Clink!

Kind Regards, John

 

[RF Lighting]

Spare a thought for those of us who are just heading in to work

 

[JohnW2]

Spare a thought for those of us who are just heading in to work

Your time will come, after work

Kind Regards, John

 

[DavidA1982]

In fact, we are now told that it is a 40A MCB, not a 32A one.

.... out of interest, the electrician who put that circuit in had installed the 6mm cable in mini trunking. Is that a problem?

Also: the cables for part of the existing kitchen circuit were simply left lying on the floor under the units (behind the back legs). Part of me thought it was untidy having cables running along the floor, but on the other hand I didn't want to go putting them in trunking or clipping them to the wall as that might alter something. In the end, I simply left this as-is i.e. with the cables lying loose on the floor under the (new) kitchen units. Would it have been better to tidy them up and get them off the floor by putting them in trunking?

 

[ban-all-sheds]