Oven Connection and Breaker Size

[TheScullster]

Hi all

For various reasons, my kitchen project was put on hold last year, but this is now back on the agenda.

Some of you may remember the issues I had with the council inspector about diversity calculations etc. This was resolved by Adam W re-working the cooker circuit and providing Part P documentation.

Anyhow - we have been looking at oven selection, and SWMBO says that a single oven will be sufficient for her needs. So we have a single 32A supply split to feed 2 locations, one for the hob the other for the oven.

The oven being considered has a total connected load of 3500W so max current draw 15A. Is it an issue to connect this to the 32A supply given that the level of protection will not be close to the max device rating?

I do not have the option of running a dedicated cable to this point. Nor do I have a suitable place to introduce a local breaker.

TIA

Phil

[John Rumm]

Unless the over actually specifies a need for protection at a particular level (unlikely) its not a problem (in fact fairly typical)...

[ARWadsworth]

I agree.

[ARWadsworth]

You could lift all your nice carpets and chisel down your newly plastered walls to lay a new cable:-)

Have you got a link to the suggested oven?

[TheScullster]

"ARWadsworth" wrote

Hi Adam/John

I really thought that this cooker circuit malarky was done-and-dusted!

Anyhow, the oven that SWMBO is now leaning towards is here:

is hard wired according to Bosch tech support, although the response to my enquiry to them carried the name Neff! They state a required supply of 16-20 amps. I'm not sure what the impact will be of simply connecting this to a 32A supply. Now that we have earth leakage protection on the circuit, it is clearly better protected than previously. But I guess it all depends on the type of fault.

As John suggests, I'm quite sure there will be thousands of installs (like my current setup in fact) where a single 32A supply is looped between separate oven and hob irrespective of their individual power requirements.

Just noticed that the link above claims that cable will not be supplied, but the Bosch Tech Literature says it will. If there is no cable, what do you recommend for the oven and also for the hob below? Is some sort of heat resistant cable required or is it the old

6mm as existing?

input, as always, would be appreciated.

Phil

[John Rumm]

> It is hard wired according to Bosch tech support, although the response to

Yup, since its max load is over what you can draw from a plug.

The impact is that it will work nicely ;-)

(I think you are overthinking this!)

In reality earth leakage protection for ovens is of no real benefit anyway. The scenarios in which you could receive a shock from the thing are vanishingly few, and exceedingly unlikely. However the times you might have an ageing element that would work fine were you able to power it long enough, but will now need replacement sooner are significantly greater.

Indeed. As the OSG says, a total load of up to 15kW connected this way is quite normal.

There is no mention on the oven spec of needing any specific level of fused protection (which is much as you would expect). (I looked for the proper manual on the bosch site[1] - its fairly content free!). So it will be fine on the 32A circuit. The only real protective need is fault protection for the cable - and that is adequately taken care of by a B32 MCB

The ideal stuff is:

many wholesalers don't seem to stock anything over 2.5mm^2, which is probably why most real world installs you see are done in 6mm^2 T&E

[1] The one with the UM type of II:

[TheScullster]

>>> It is hard wired according to Bosch tech support, although the response >> to

Thanks again John

You're right about the over-thinking. It's probably paranoia after the council inspection episode!

Phil

[ARWadsworth]

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We do not have any. Sorry.