Domestic Kitchen Advice

rsmck · Aug 4, 2011

We are installing a new kitchen with the following cooking appliances - Combination Microwave rated at 3.2kW, Oven rated at 3.55kW and Hob rated at 7.2kW making a total of around 60A!

The plan was to supply both the oven and hob from a 45A cooker connection unit with a DP isolator protected by a 45A MCB supplied by 6mm T&E from a consumer unit located less than 1m (on the other side of a wall) however then my better half decided to add the combination microwave to the mix.

The kitchen also has a 4mm2 radial circuit supplying the rest of the worktop 13A outlets (and a single dishwasher) and a dedicated socket (on a non-RCD-protected MCB) for the Fridge/Freezer only.

Would you connect the combi oven into the same connection unit and isolator as the other oven (and hob) or just connect the combination microwave into a normal 13A plugtop and outlet ? Alternatively I suppose could run a second 6mm cable from the 45A MCB to a separate isolator for the two ovens (combi+normal oven) and leave the hob on the other isolator - but whilst I can't find anything which would prohibit this it does seem a bit, well, unusual.

Any advice would be greatly appreciated.

[E2A: I know I had a similar thread a while ago, but the kitchen requirements have changed rather a lot (as have many things!) so it seemed more appropriate to start this one]

Voltimax · Aug 6, 2011

Engineer 54: As I have pointed out part p states manufacturers instructions should be followed not me, so it's no use getting upset with me. You have to remember that anyone carrying out domestic work has to follow BS 7671 and Part P. Let's also not forget that Part P is a statutory document but BS 7671 isn't, believe it or not, it carries more weight.

I don't believe what's written in manufacturers instructions most of the time and I'm more than capable of determining whether something should get it's own circuit or not, but I run a business and I don't want or can afford comebacks, so, if the manufacturer wants a 16A circuit they can have one, so long as they're not asking me to go below the minimum standard I don't care.

Engineer54 · Aug 6, 2011

Far from getting upset with you Votimax, Just that far too often these manufacturers instructions, ...if you can actually call them that, are contradictory to to our wiring regulations. And when you calculate the full load that these cooking appliances can ''actually'' provide/draw, makes providing a separate circuit, pretty much wishful thinking!!

As i said earlier, i'd like to see companies like NEFF fight that in a court of law, i'll wager they wouldn't!! As i said before, it's fine if you want to provide a separate circuit in a kitchen refurb or new build, but what about in an existing finished kitchen, where there is no way, to supply that appliance other than say, via an existing ring circuit??

As for the Part Pee thing and the BS7671, agree it makes no sense at all, but then the IET never wanted it to be statutory document. It would mean a lot of tidying up, to make it legally tight enough to stand up in a court of law, even though it has been used as such in certain types of class actions...