SMEG and 13AMP

[salihtas]

Hi folks,

I'm about to wire in my 14.4Kw SMEG A1-5 cooker. It comes with 13AMP plug. Clearly the cooker needs more than a 13AMP circuit. So I am installing a 45AMP switch and running 10mm2 cable to/from the consumer unit with a 30AMP MCB. My question is why does the vendor supply a 13AMP plug when the power it consumes is going to above 13AMP. Also the cable to the cooker from the cooker connection unit is much smaller than the cable I'm gonna lay to/from the consumer unit.

Am I missing something or is this how cooker are?

Cheers,

Tas

 

[Big_Spark]

Well if you didn't notice the cooker is Dual Fuel.

The burners are GAS, the oven is electric, and according to SMEG this particular over has a rating of 2850W (2.8kW) which is a little under 12.5A, that is why they put a 13A plug on it.

The TOTAL rating of the cooker is 14.4kW, but the bulk of that output is via the Gas burners.

It does pay to read the instructions with appliances before you spend money on unecessary works, it also helps to understand the appliance, it will save you doing anything to it that will invalidate your warranty, like cutting off a moulded plug!!

 

[salihtas]

Now that is what I call fast. Many, many thanks for your reply. The mud has now cleared.

So I guess it's OK to simply plug it into a normal socket?

Cheers,

Tas

 

[ban-all-sheds]

Salihtas - even if you did think it was an all-electric device, how did you arrive at the combination of a 14.4kW appliance, a 45A switch, a 10mm cable and a 30A MCB?

And also, if you bought what you thought was an all-electric cooker, do you have gas?

 

[salihtas]

Well I was wondering why the electric oven was so powerful - never had an electric oven before. I think I must have speed-read the instructions cos the install guide advised me to look at a specific plate on the cooker with the KW rating, so I assumed this was for only the electric not for the electric and gas output combined.

So, I thought 14.4Kw support would need:

14400/230=62amps (max).

Suggested (from Which! electrical Guide) MCB = 10amps + 30% of max = 28amps. Hence the 30amp MCB. I went to 10mm cable cos I wanted to be sure it was up for the jump stead of 6mm cable, plus I had a run of 8m from the consumer unit to the cooker.

I wasn't too sure of the calcs because the book I was using assumed a fully electric cooker - with not all hobs/oven/grill would be on at the same time, whereas my oven is the only electrical draw so the equation didn't..equate.


You have to remember that I'm new to this so I was did some research and come up with these numbers and needed to run it past knowledgeable people.

Now I feel like a plank - but I guess you learn from your mistakes.

Cheers,

Tas

 

[Big_Spark]

Tas, no need to feel a plank fella, we all have to learn, and we have all done something similar at some time on our lives..It's called life

I didn't mean my comments about reading the instruction to sound condecending or patronising, I was in a rush at the time and didn't re-read it before I pressed submit!!!!

 

[ban-all-sheds]

Suggested (from Which! electrical Guide) MCB = 10amps + 30% of max = 28amps. Hence the 30amp MCB.

I've seen that before - and not just in DIY books, but also in the IEE's very own On Site Guide.

BUT you need to understand the context of that advice. It is to do with estimating the maximum demand for an installation, not an individual circuit. In other words that calculation is what you do when looking at the loading of a whole house, adding up the likely simultaneous total for ring mains, shower(s), lighting etc etc. Each individual circuit still needs to be properly designed, and were yours to be a restaurant sized 14.4kW electric cooker it is possible that you would turn everything on at once. The diversity guidelines assume that you wouldn't do that AND have every light on AND have a 3-bar electric fire on in every room, AND be running the washing machine, tumble drier and dishwasher...

You have to remember that I'm new to this so I was did some research and come up with these numbers and needed to run it past knowledgeable people.

Good idea

Now I feel like a plank - but I guess you learn from your mistakes.

Indeed you do, but there's no need to feel like a plank - if I had one for every time I'd felt like one, I'd have enough for this summer's decking project. And anyway - far better to feel like a plank for asking what turned out to be a daft question than feeling like a plank for doing something daft with your electrics.

 

[salihtas]

Thanks for the advice. Much appreciated.

 

[kendor]

I didn't mean my comments about reading the instruction to sound condecending or patronising, I was in a rush at the time and didn't re-read it before I pressed submit!!!!

From reading a few of the other posts in this forum it seems you've been in a bit of a rush in submitting posts before

you can be knowledgeable and helpful without treating others as plebs

some people just forget things sometimes and are only after jogging their memories not having to be lectured by others!

 

[Big_Spark]

From reading a few of the other posts in this forum it seems you've been in a bit of a rush in submitting posts before

you can be knowledgeable and helpful without treating others as plebs

some people just forget things sometimes and are only after jogging their memories not having to be lectured by others!

Kendor, if you've nothing to say but having a dig, I suggest you don't say it.

 

[Albert]

As a new one myself, I feel the same as salihtas, may be I would not use the 14.4KW value but using the 2.8KW, still for a domestic cooker or oven I would calculate the current demand the same way and take in consideration the diversity factor from the IEE on site guide. Is it wrong?
thanks, Albert

 

[Big_Spark]

As a new one myself, I feel the same as salihtas, may be I would not use the 14.4KW value but using the 2.8KW, still for a domestic cooker or oven I would calculate the current demand the same way and take in consideration the diversity factor from the IEE on site guide. Is it wrong?
thanks, Albert

Albert, you need to remember that the Guide is exactly that. You need to assess, as best your able, exactly how your going to use your cooker/hob whatever.

I personally always assume that at some point the appliance will work at full load, normally christmas time in the case of cooking appliances, so always wire accordingly. I look at it if you take the worst case scenario, your covered, HOWEVER, I install for others so do not have the luxury of knowing how the equipement will be used in practise.

To be honest it is a tough call to say it is right or wrong, my personal feeling is to say it is wrong, but that is personal, the IEE state it is OK to calculate that way, so who am I argue

 

[ban-all-sheds]

As a new one myself, I feel the same as salihtas, may be I would not use the 14.4KW value but using the 2.8KW, still for a domestic cooker or oven I would calculate the current demand the same way and take in consideration the diversity factor from the IEE on site guide. Is it wrong?

AFAIK, those diversity guidelines are for assessing the total demand of the installation. So your cooker circuit should be sized and protected such that you could safely have it running flat out, but when determining the total of the whole house you allocate 10A +30% of the remainder +5A to that circuit.

Or am I wrong?

 

[Albert]

As always thanks for the help, just to make it more complicated (and to understand the issue), imagine a unit that can demand 16KW and another one 18KW, without diversity, we will need two MCB's one of about 70A, and the other about 78A, if you would have this kind of situation at home and will not use diversity factors, considering the rest of the circuits in the CCU what size of RCD and/or main fuse will be used? again this is not a sarcastic or provocative question, it is just to understand your reply
Thanks, Albert

 

[ban-all-sheds]

non sarcastic or provocative answer - you can't get 70-80A MCBs, so you'd be outside the range of domestic circuit protection devices and wiring accessories. I don't know the answer to your question, but I suspect that at 150A for just those two items it would involve a 3-phase supply.