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New and Replacement Electrical Ring and Building Control

Postby Chyaweth » Thu Jul 25, 2013 11:44 am

my first post and almost certainly not my last.
We moved into a five bedroom house last year that had obviously once been a B&B.
The wiring was a nightmare and the local electrical firm blanched when they saw it.
They've made it "safe" and also put in a new CU with RCBO's.
They advised me to totally rewire the bedroom plinth heaters that use a four wire circuit. (Fourth wire for a master controller). To that end I'm now running new four core cable in a proper ring style to all the bedrooms.

Whilst doing the above wanted to also run a new ring to supply undersink water heaters for the vanity units.

I can say, "hand-on-heart", that I shall get the electrical firm to come in and do all the necessary checks and final connections to the CU but am worried whether I should have informed Building Control.
Also, will I need to leave access for the cable runs to be checked under the floorboards?

Thanks in advance.
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Postby ericmark » Thu Jul 25, 2013 8:29 pm

You don't say where you live and informing building control varies around the UK with Scotland, Ulster, Wales and England all being different.

On another forum there was a heated talk about what a "New Circuit" is and also when a "consumer unit" is not a consumer unit but just a distribution unit. In the end it was agreed one would need to let the courts decide which in real terms is unlikely to happen. This was brought about because of the new English rules and does not affect Wales.

So what is more important is what the electrician you use will accept. There is now provision in England for scheme member electricians to test and inspect third party work but the scheme operators have not developed a system to allow this to take place.

So sorry it's up to you to decide what to notify so now onto the work you have referred to.

1) A final ring circuit is a type tested UK system which has a very strict set of rules attached to its use. One of the rules is no permanent attached appliance 2kW and over so in the main a final ring is not used to power room heaters even though during world war two when it was designed that was the aim of the design.

2) There is a 3kW limit to using FCU's so common to use a dedicated consumer unit to power off peak heaters so an array of MCB's at 16A can be used allowing heaters over 3kW to be included. It also allows a one switch kills all to switch off the heaters.

3) The more modern approach is to also include items like tumble driers and washing machines to take advantage of the off peak power so there has been a move to using control wires and using local switching rather than main relay to switch the heaters on and off but this still has the problem of using over 3kW heaters so one still uses radial rather than ring methods of wiring.

So what you need is to "design", "install" and "inspect and test" and for each of the three functions you have a space for the person doing the work to sign the installation certificate. This then causes a problem under English Part P as once one uses an installation certificate one admits it's a new circuit so you will need to inform the LABC before the work starts.

With a "Minor Works Certificate" there is only provision for one signature so you will need to do all your own inspecting and testing and fill in all the readings.

So before you start you need to consider the design. No good once started it needs you to select the method before you touch a single cable.

Working through the LABC can be expensive and also it's pot luck on what the inspector requires. My son in Liverpool found the inspector very helpful and reasonable but in Flintshire in North Wales he refused to accept my sons signatures on the installation certificate even with a C&G 2391 and at that time C&G 2381 (Now C&G 2382 has taken over). He would however accept my degree in electrical and electronic engineering which really was not as good for the work in hand as the C&G 2391.

So since you have started I would stop straight away and try and find a friendly electrician willing to allow you to do the donkey work. My son at one time did agree to some one doing that but was messed about so much with work not being done on time and so having to do more than agreed himself he vowed never again. All or nothing. About only exception is allowing them to dig garden trench. Many electricians have had the same problem so to get one who will help is like looking for that pile behind the rocking horse. However you may be lucky.

Other option is to register the work but at the moment there seems to be no new set of charges for the English counties so no idea what you will be charged it could mean £250 to register the work plus extra to get it tested.

Or of course brake the law. This could affect insurance and make selling the house harder but again no real way to know until some thing goes wrong.

So I would say you need to consider your own skills. My 17th Edition test set cost my son £750 and to hire is still going to cost around £75. For the C&G 2391 there was a 50% failure rate and this is for electricians for a DIY guy to do his own inspection and testing is really some mammoth task. The forms are free down load from IET. Google "iet forms for contractors" and have a look.

Try same question on other electrical forums you will get loads of abuse. We try to help here. However they will likely also direct you to sites where you can down load and buy books but the same thing which limits abuse also stops links. Some are permitted but I have given up trying as it messes up thread when removed.

Anyway at least say where you live in UK and also wait and see if any of the others answer you. SparkX is very good but not seen a post from him for some time.
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Postby Chyaweth » Fri Jul 26, 2013 8:56 am

Many thanks for a very comprehensive reply.
We live in North Norfolk and, when we had the building inspector around to check the first stages of our loft conversion, he appeared a very friendly amenable guy with lots of suggestions for doing things easier and cheaper.

What is obvious from your reply is that, before I go any further, I must get in touch with the electrical firm and ask them what they are willing to allow me to do with them still doing the finishing, checking and certification. Hopefully they will also advise on the, "new circuit", conundrum.

Allowing non-qualified persons to do some of the "donkey work" does have pros and cons.

I was a licensed aircraft engineer at Heathrow for many years. My qualifications allowed me to certify aircraft like the Boeing 747 as fit to fly. This I would do many times a day and wave a plane-full of passengers off to their destination. Company practise changed and they recruited semi-skilled mechanics and I was asked to certify their work before signing out the aircraft.

On the one hand I was saved all the filthy jobs like brake changes but the downside was how trustworthy these mechanics were and also the reduction in jobs for fellow licensed engineers.

I'll keep you posted on how I get on, Thanks again.
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