Ring Main Question

lisal0u · 2 March 2009 at 2:46PM

Hi,

My Dad, who is a qualified electrician but not Part P, is re-wiring our house. It is a small 3 bed semi. He has wired it with just one ring rather then one for upstairs and one for downstairs. Is this going to be a problem when the council come to give us our part P certificate?

Also we are just connecting everything to the consumer unit which is a 10 way but there will be no spare capacity. There is no room where it is to have a bigger box. Will this also be a problem as it suggests that you have spare capacity in the unit?

Any advice would be appreciated. I have contacted the council on these matter but am waiting for a response.

Many thanks
Lisa

Canucklehead · 2 March 2009 at 3:07PM

Good afternoon: If I am following what you have said correctly the property has one ring main and yet your 10 way consumer unit has no spare capacity

.

Canucklehead

latecomer · 2 March 2009 at 3:42PM

Surely if your dad is qualified he will know whats acceptable? If not then he should know someone to ask? I'm pretty certain there is a maximum run length specification for a ring main but it may be a recommendation rather than a requirement.

robv_3 · 2 March 2009 at 4:27PM

latecomer wrote: »

I'm pretty certain there is a maximum run length specification for a ring main but it may be a recommendation rather than a requirement.

not directly but there is a maximum area a ring should cover which from memory is 100m2 but this was back in 15th edition days

lisal0u · 2 March 2009 at 5:03PM

Yes it is one ringmain and the 10 way consumer unit is full. It has in it:

Ring main
Upstairs Lighting
Downstairs Lighting
Oven
Undefloor heating kitchen
Underfloor heating livingroom
Underfloor heating Bathroom
Boiler
Bathroom radiator heating element
Garage

We have a copy of the 17th Edition but its very vague about the ring main. The council have got back to me about the spare capacity and say it is also a grey area! How helpful! They said they they would not fail our installition because the consumer unit was full but would like it to have spare capacity.

I then asked him about the ring main and he got a bit shirty saying that my electrician should know which is fair enough!

My Dad has said that the ring main is adequate for the load that it will have to take but we will have to check the length of it. I have read in a few places that it shouldn't be longer than 106m which I expect it is.

I think my Dad is cursing the day he said he would do my re-wire!

Thanks for your advice!
Lisa

ABN · 2 March 2009 at 6:02PM

lisal0u wrote: »

Hi,

My Dad, who is a qualified electrician but not Part P, is re-wiring our house. ..... Is this going to be a problem when the council come to give us our part P certificate?

confused here.

Thought that, for kitchens and bathrooms in particulaar, that the electrican HAD to be Part P certified as it was not possible to get someone who has not done the work to give a certificate.

Whilst the wiring may pass "external" checks there were other factors such as the depth and routing which would not be visiable but still need approving.

lisal0u · 2 March 2009 at 6:20PM

ABN wrote: »

confused here.

Thought that, for kitchens and bathrooms in particulaar, that the electrican HAD to be Part P certified as it was not possible to get someone who has not done the work to give a certificate.

Whilst the wiring may pass "external" checks there were other factors such as the depth and routing which would not be visiable but still need approving.

Hi,

I have paid the council (Building Control) £175 to do supply me with the Part P certificate. They have been several times to check the first fix and wiill be sending their electricians to do the final test when it is all finished. So an electrician that is not Part P certified can do the work if you pay the council to check it.

Lisa

Canucklehead · 2 March 2009 at 6:23PM

Hi
Is the oven a combined hob and all electric? Or gas hob electric oven?
Is the boiler gas?

Corgi Guy.

lisal0u · 2 March 2009 at 6:39PM

Canucklehead wrote: »

Hi
Is the oven a combined hob and all electric? Or gas hob electric oven?
Is the boiler gas?

Corgi Guy.

Hi,

The oven is an intergrated electric oven and we have a seperate gas hob. The boiler is gas also.

Lisa

Canucklehead · 2 March 2009 at 7:03PM

Hi

I'll assume your description of the consumer unit is correct.

Take out the boiler from the consumer unit No need as it can be run from a fused spur or unswitched socket from the downstairs ring or kitchen ring
This gives you another ring main.
Take out the oven from the consumer unit. Most ovens run on a three pin plug as they are 3kw.(check the oven first though)
This gives you a kitchen ring.

One ring main for a whole house is only going to give you grief.IMO.

Corgi Guy.

mikey72 · 2 March 2009 at 8:24PM

I don't know your installation, or where your boiler is, or what size your oven is, but I wouldn't take this advice without checking the 17th edition. Ovens over 2kw need a dedicated radial. Anything in the bathroom needs to be wired through the RCD in the consumer unit,including the lighting circuit. The ring usually supplies up to 100 sq metres if it has a 32A trip. But it is specific to your house, and whatever spilt load consumer box you have. Don't take advice without letting someone see the installation first.

Ring Main Question

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