New oven wiring

ic

I'll soon be fitting new appliances in the kitchen. As it stands there is a cooker switch that switches an outlet below the worktop, and offers a plug, plus is spurred to supply under cabinet lighting and a cooker hood. The cooker switch itself is currently not used as I have a gas cooker. The cooker switch is wired to 6mm2 cable, running approx five meters from the fuse box, fused by a 32A mcb.

The new setup will be:

0.92kW oven
9kW hob
180W hood with lights
60W under cabinet lights
+ I normally use the socket to run a cordless phone

This makes a total of 10.16kW, which I believe would be 44A (just divide the watts by 230V). Would I be safe to simply get the MCB uprated in the fuse box to 45A, or should I be looking to get a separate supply run on the kitchen ring for the oven, as well as uprating the MCB?

As I understand it, the existing MCB is insufficient for the hob on its own (32A = 7.3kW max).

TimBuckTeeth

You should never replace a fuse or MCB with a higher rated one. The main function of the MCB is to protect the cable from excess current which would cause it to overheat.

The 6mm cable needs to be replaced with 10mm cable to carry the power needed, a 45A MCB (40A or 50A are more common values) would be safe to use with 10mm cable.

phill99

I'm not convinced you have the correct information here. You say your oven is 0.92kw. I think that must be an error. Most ovens run at 4 - 7 kw. You are saying it is less than one third of the power of a standard kettle. I think you might need to look at the specification again.

ic

The oven is this one: http://www.ikea.com/gb/en/catalog/products/20123750. Looking around on line, most A-rated ovens need around 800 watts.

Energy class: A.
Energy consumption with a standard load, top and bottom heating: 0.79 kWh.
Energy consumption with a standard load, pastry function: 0.92 kWh.

From reading around online, I thought 6mm2 cable was capable of carrying a 45A load max?

Also reading around I've found out that domestic circuits tend to be installed with "diversity" in mind (see description in fourth post here). Although the hob I'm getting is 9kW, thats assuming all four rings are running full blast along with the boosters. My beans on toast don't tend to require such volcanic temperatures, so by the sound of things I should just leave the 32A MCB in place and rely on the fact that the worse that can happen is that the MCB trips because the hob has attempted to draw too much power?

According to the example, posted in the other forums, 10A + 30% of the remainder (9A) + 5A for the socket = 24A, which is well within the capacity of the existing circuit. I'm definitely going to get the oven put on its own fused connection to the normal kitchen ring.