i have a 6mm cable coming off a 32a breaker from my main cu. This goes to a junction box with a 6mm cable going to my electric oven and another cable supplying a second cu in my kitchen which is used for my lights and ring main of my kitchen. Is this ok or do i need to run a separate cable from my main cu to the oven?
It's not correct but likely not dangerous either. From what you say I assume should there be an overload the 32A MCB will trip. So in essence it fails safe.
The 17th Edition or BS7671:2008 does tell us that items over 2Kw should have their own dedicated supply. But this is written to cover all and a supply to just a kitchen may quite easily work with just a 32A supply.
Without looking at the layout it's impossible to say which method would best suit. My parents have a 16mm SWA cable feeding a consumer unit for just the kitchen in the kitchen which works fine. It was fitted in the main as my mother can't get under the stairs to reset any MCB or RCD which has tripped.
It's not just what regulations say but also what makes sense for your property. Where cables can be safely run with easy and what they will look like.
Because special location so Part P charges for DIY are high I would suggest you get a scheme registered electrician to look at what needs doing and give a quote. This should do two things. 1) You will know how he would do the job so could emulate it. 2) You will see if it's really worth doing it as a DIY.
One of the problems is that new stuff has to follow new regulations even though old stuff can remain as it was. So adding RCD protection could cause problems. SWA or Mineral insulated cable does not need RCD protection but installing the latter is not a DIY job and even SWA can cause problems.
If once he has visited your not happy then start a new post and ask what is bothering you. I say new post as I often look for posts with no replies so likely to get a faster reply from new post than old one.
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