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[bilby]

Hi,i am installing a new kitchen and need more sockets.There is one downstairs ring and one upstairs.Should i find the leg that feeds the kitchen and the leg that leaves the kitchen,join them up to re make downstairs ring and wire totally new ring for kitchen .thanks for any replies

[BLAKEY1963]

[quote="bilby"]Hi,i am installing a new kitchen and need more sockets.There is one downstairs ring and one upstairs.Should i find the leg that feeds the kitchen and the leg that leaves the kitchen,join them up to re make downstairs ring and wire totally new ring for kitchen .thanks for any replies[/quote]

BILBY
After notifying local authority building control , you could wire a new kitchen ring main . LABC will explain the testing requirements and test forms they would require from you .

BLAKEY1963

[ericmark]

As already said you need to work with the LABC and satisfy them. However one has to be very careful with ring mains to ensure they are a single ring not a figure of 8 and any spurs have only one socket. Unless you have detailed plans it is very easy to make mistakes when splitting and joining rings.

The test procedure is quite exhaustive and you will need a set of special meters. These will cost around £75 to hire or £750 to buy.

If you are already under the control of the building inspector it's not so bad but if only the electrics require the LABC then their minimum charge of £100+ makes it uneconomic to DIY.

With the washing machine, tumble drier, dish washer, and kettle often found in the kitchen the loading can be high and add to that the hob and oven it is not uncommon to have a sub-main to power the kitchen. However it is all down to what is already installed and there is no one size fits all. Often the reason for a sub-main is more to do with RCD protection where the original CU has no RCD fitted.

If you do want to DIY there are people on here who will help. But first do look into costs as likely due to LABC and hire charges it is better to used an electrician who is a member of a scheme and can self certify.

[bilby]

thanks both of you.would there be anything in the regs against leaving all existing wiring,putting in another ring in kitchen,thereby having one downstairs ring which included kitchen and another ring in kitchen and putting a warning notice on consumer unit saying sockets in kitchen are on 2 different circuits.

[ericmark]

The regulations will permit it. What it says is:-
514.1.1 Except where there is no possibility of confusion, a label or other suitable means of identification shall be provided to indicate the purpose of each item of switchgear and controlgear. Where the operator cannot observe the operation of switchgear and controlgear and where this might lead to danger, a suitable indicator shall be fixed in a position visible to the operator.
514.1.2 As far as is reasonably practicable, wiring shall be so arranged or marked that it can be identified for inspection testing, repair or alteration of the installation.
In practice it is common to put a small sticker on the socket with the number of the MCB supplying that socket.

[bilby]

thanks again,what about if i have an electric hob one side of kitchen and electric double oven on opposite wall,i take it a 45 amp double pole switch on own circuit for hob,and find out what oven is rated at .presume that would be on own circuit also and not on the ring.

[jimmy_one_ball]

Yes it is common to have a seperate 30A/32A ring final circuit for a kitchen due to the modern appliance loads involved. What you said in your first Q would be fine, just remember all conductor joints must be left accessible.

The oven will need to be on its own circuit, the cable calc for that is a little involved as there isn't a standard cable size or breaker rating for an oven. Give me the ovens wattage and I'll do an ad hoc calc to give you an idea of what may be needed.

As for the hob, again what is the power/wattage rating? Don't just assume 45A breaker rating as there isn't a one size fits all, circuit protection must be carefuly selected.

As the other guys said there are no laws to stop homeowners from doing DIY electric works, however the work must be verified.

[ericmark]

When wiring a kitchen one has to carefully look at the manufactures recommendations. Many cookers, hobs and ovens have the supply stipulated by the manufacturer mine for example states 32A. So if I had a 10mm sq cable with a 45A RCBO then it would need the RCBO changing to lower size because of the manufacturers recommendations. However some non British manufactures as for larger than expected supplies many ovens are 16A rather than the British 13A and much depends on the selection permitted.

Personally I prefer stand alone oven as most of the built in use a relay which shares the power between conventional top or bottom heating and fan. Where with stand alone ovens the top, bottom and fan can all work together. My Belling allows one to select how the oven is heated and is both conventional and fan but my mothers which is built in has far less control.

The hobs today can take huge amounts of power. One ring on my hob is 3.6 kW where my mothers is only 1.6 kW for largest ring. With such large variations between different makes and types a lot of care is required when planning. Most if not all Domino hobs are less than 3 kW but some of the larger induction hobs can be 10 kW so much care is required. Range hobs which one expects to take a lot of power often take less than normal stand alone because of internal switching which stops too many elements switching on together.

The same applies to other items a washer/drier needs less power then two separate units in general however there are now driers designed to take 6 hours using a lot less heat and designed to run overnight.

No two kitchens are the same and one of the problems is lack of paperwork from electricians in the past. We look at a cooker outlet which is supplied with a 32A MCB and 10 mm sq cable and we have no idea if the MCB was reduced to 32A because the cable runs through insulation or to comply with manufactures recommendations. Only when the electrician has noted on paperwork fitted with 10mm to allow upgrade to 45A if hob is changed can we change the MCB when cooker is changed to a larger one.

Some things we can measure. The main one when considering what can be supplied is the earth loop impedance. Some figures stick in the mind and without looking it up I know for a 32A supply (B32) I am looking for 1.44 ohms or less. But for other sizes I would need to look up or calculate. This is where the DIY falls down. The meters I use cost around £750 and are beyond the pocket of most DIY people. We are told we can calculate instead of measuring but in practice that means measuring exactly the length of cable used and does not test for any bad connections.

For an electrician to become a member of one of the schemes he needs to own around £1000 worth of books and meters plus have qualifications to show he can use them. In industry the electrician does not need anything. I is assumed the employer will satisfy himself the guy can do the job safely and if the electrician for example came for Poland he may have no British qualifications. But for Domestic he would have to own all the books and meters. Some schemes want more than others but C&G2382 would be minimum requirement.

Although Part P will allow DIY really this allows an industrial electrician to do the odd job on Domestic without becoming a member of a scheme and is not really to let the untrained DIY guy to do his own.

To jump through all the hoops is not easy. And unless you have some formal training I would suggest better not to DIY. Not only because of danger but also the expense. It can cost more to go through LABC than you would pay a registered electrician. So why bother to DIY?