Cooker and hob wiring

Oh what fun, another battle of: it says this; no it says that; or it really means this. :D.

First the electrical principles - always a good place to start.

The cooker and hob came as a set but the oven has a standard plug on it. Can the oven be wired into the same junction box (old cooker connection point) as the hob? The junction box is rate at 45 amp and this is then connected to a CCU on a 32 amp mcb in the Consumer unit.

The hob is 6600W and the oven states a max of 2400W.

So I assume we have an existing 32A radial circuit. We now wish to connect cooking appliances with a total load of 6600 + 2400 = 9000 watts which at 230 volts means a maximum possible current flow of 39A.

Can a 32A circuit supply this load without damage - in a domestic environment it is unlikely that all of the load will be demanded at once, and even if it is the thermostatic controls will soon start to operate thus reducing the thermal load on the circuit. So unless there is some unknown factor, this arrangement should be adequate.

Does the circuit need overload protection - quite simply no. It cannot produce an overload so 433.3.1 (ii) applies.

Can one radial supply two appliances - yes.

So from an electrical principles point of view - do we have a problem - no.

Now the fun part :D

First we have not been given sight of the manufacturer's instruction so we don't actually know what they say. It may be something like - this appliance must be installed by an electrician.

Why have they fitted a plug - well probably to avoid some perceived risk of prosecution under 'The Plugs and Socket etc. (Safety) Regulations 1994' (you can find them on the web). Part II is applicable here - they may be concerned about Regulation 12 - basically this appear to say that any appliance rated at > 200 volts and < 13A should have a 13A plug on it.

Now I am not going to try and second guess a courts view on that lot, but many manufacturers fit plugs because it avoids any later problems with Trading Standards inspectors :D.

So do we have to comply with manufacturer's instructions - well it depends what they are. If a misguided manufacturer gave instructions that would cause danger, would you have to comply - well your honour - they told me I had to do it (I have heard that defence before somewhere :D).

What about 134.1.1 - I'll raise that - what about 120.3.

Have fun :D.
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Don't be a silly billy Bas. It isn't possible to follow certain manufacturer's instructions to the letter. Because certain manufacturer's clearly have not a clue - let alone a basic understanding of the English language.....
It's an offence to supply equipment with inadequate instructions.

It's very easy to spout Regulations, but not so easy to comprehend them.

I'm quite content to take into account the manufacturer's instructions inasmuch that it might affect any warranty. But I'll be blowed if I'll accept any Tom Dick or Harry's instructions over and above the Regulations and my own commonsense........
134.1.1 ....Electrical equipment shall be installed in accordance with the instructions provided by the manufacturer of the equipment.

Not sure why you don't find that easy to comprehend....
I have no difficulty with 134.1.1, Bas. It's quite clear in its intent. I do have a problem with your final remark, lacking as it does, the proper use of subject and personal pronoun.......

"Hello, can you fit an oven for me? I bought it from e-bay"

"Do you have the manufacturer's instructions?"

"Er, no. Is that a problem? I mean, it has a prewired cable, can't you just come along and connect it to the existing switch?"

"I'm afraid not, madam. You see, it isn't allowed to install any apparatus without the instructions. If I were to do so, I would be in trouble with the Regs and Ban-all-Sheds - so it simply isn't worth the risk".........

134.1.1 ....Electrical equipment shall be installed in accordance with the instructions provided by the manufacturer of the equipment.

what's so hard to understand about that?

if you don't have the instructions, then you can't install in accordance with them..
in that case you wire to the GENERAL regulations that govern that type of equipment..
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Well maybe we should all comply with a manufacturer's instructions, whatever they might be.

How about this one:
Installation should be carried out by competent tradesmen in accordance with the detailed fitting instructions supplied with every unit and in accordance with water regulations.

That is from a Triton shower.

So sorry all you competent DIY people - you are not tradesmen (you don't trade) so get your cheque books out :D.

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