by ericmark »
Tue Nov 15, 2011 9:02 pm
There are a number of problems and to be fair we need to point out as many as we can so you will realise what the job entails. If you still think you can do it great but not quite as easy as you may think.
The cables will likely in the main run under the floor boards and you can't really do a room at a time as the cables run from room to room so while doing the job you will have to remove all carpets in order to get to floor boards.
The work will need inspecting so you will need to involve the county council building control (LABC) and I don't know if there is a time limit between starting and finishing. We as electricians can self certify so are not directly involved with the council.
There is also planning which will include some maths and the testing and inspecting. When we run a circuit we have to ensure if there is a fault it will auto disconnect (The MCB will trip) if there is too much cable this will not happen. The amount of cable will vary according to the MCB used. For example with a B32 MCB the limit is about 106 meters with a ring main. However I would never take to limit normal is to consider one role of cable per ring main. Once completed this will be tested. This is another problem.
The test gear costs around £750 although one can hire. But even to hire (Normally min of one week) it will cost around £75. There is also the problem in using it. Although some tests are done dead, some need the circuit to be powered and incorrect procedure can give people shocks as a result of the testing.
Another problem is to get the LABC to accept your readings. This can be a challenge working on my parents house they would not accept my son doing the tests, who holds a 2391 and 2382 city and guilds exams to show he is trained to do that work but would accept me doing the tests with a degree in electrical and electronic engineering. I did also have the 2391 and 2382 but they did not know that and the 2391 was really what they should have been looking for.
On a re-wire you will need to comply with BS7671:2008 soon amendment 1 will be active which will likely mean RCD on all circuits. Not bought amendment 1 yet so still working on BS7671:2008 also called 17th Edition. Even electricians argue as to what is and is not permitted. I do not envy you trying to conform.
Some building regulations will also raise their head. In the main Part P, but the other parts may also be referred to many items like socket heights are not a problem with re-wire they are only for new builds but a lot depends on the attitude of the local building inspector.
So way forward:-
First work out what you want and make a detailed plan.
Next visit the LABC and present them with the plan and see what they say.
If it seems your LABC guy is friendly then you may want to proceed. If he is one who sucks through his teeth you may think it better not to try and get the guy to play ball and that only option is a registered electrician. Believe me the attitude of the Local Authority Building Inspector is a huge factor to if worth attempting DIY.
It it is a go ahead next is plan of attack. To start on this first must be a test. If after testing you consider it likely that the existing wiring will trip a RCD clearly the re-wire must be first. However if the existing will likely not trip a RCD then changing the consumer unit to include RCD protection would be first move.
Cost and fault free operation of system do go hand in hand. Using just two RCD's you are likely to have them trip. Using RCBO's you are far less likely to have problems but it costs more. The larger the house the more one would recommend the RCBO route. With a caravan then a single RCD would do the job. This is again all down to planning.
Even as a qualified electrician I would think twice at DIY for a full re-wire. If you use a large firm they will use many electricians who can blitz the house and be in and out in a week. As DIY one should allow about 2 months working every night. More likely it will go on for 6 months. Especially considering waiting for LABC before proceeding to next stage.
Do remember I have not a clue how big your house is or how easy to re-wire. Many will comment on how other than kitchen, outside, and bathroom if not changing the consumer unit you can work without the LABC being involved. Doing one circuit at a time.
However there are two considerations when trying to bypass LABC. One is you can't advertise the house has been re-wired including informing mortgage lender or insurer if it can be insured while you are doing the work! And your work is not being inspected so any mistakes will go unnoticed. This would rather defeat the whole object of doing a re-wire.
No one else can sign paperwork as to inspection and testing only the person in control can do that. So even if a A1 re-wire it's got your name on the paperwork as person who has done the re-wire. For me not a problem I have all the bits of paper to say I know what I am doing. But for you it's some what different as I assume you don't have the bits of paper considered as showing you have the skill required. Having the skill is completely different to showing you have the skill.
People do take a chance. Finding a guy who is just starting on his own so will do a cheap job and allow you to do the donkey work is one method. However you must realise the chance you are taking he may be no better than yourself.
What would be nice is to get a reply from a non electrician who has done a complete re-wire. But never seen one. Yes seen where a guy who would normally work on commercial instruments has decided to do a re-wire. But never a guy (or girl) who has no formal training in electrical work. Even if only to become a radio ham all people who I know have done a full re-wire have some electrical qualification.
So please if you do decide to go for it. Tell us what your qualifications are, even if just an A level in physics, and how you get on.
On my house I do want to replace the two RCD's and consumer units supplied from them with a board with all RCBO's and since planned before 2004 in theroy I don't need to inform the LABC. As to if I will or not undecided as the completion certificates will make selling the house easier. I have may times tried to get my parents to get a full re-wire, because my mother is in a wheel chair likely no LABC charges. But my dad knows what it entails and will not let me do the work.
