So the time has come to have your home rewired. I'm writing this guide to give you an insight into what to expect.
First fix is the process of removing all of the old wiring and accessories from the property and running all of the new wiring into position. this is quite a labour intensive job which usually requires lifting of carpets and floorboards to create routes for the new cabling. to prepare for your first fix it is always best to liaise with your electrical contractor, as many different contractors like to work with different techniques. For a normal 3 bedroom house you can expect this stage to take around 3-5 days depending on the property and the contractor.
From my experience i like to work from the top of the property downwards and find it easiest if any furniture in rooms is moved to the centre of the room so it is easier to work around and also to make sure it can be adequately covered with dust sheets ETC.
When i turn up on site on day 1 i like to spend some time marking out where all of the sockets, switches and lights are going before starting any wiring as this makes it far easier to work out cable routes and allow for the least disruption. At this point the existing electrical system is decommisioned and we will set up a 'temporary supply' which in most cases is a board with a few sockets on which can be used to run extention leads to fridges/freezers and any other electrical items that can not be powered down during the works.
The next step is what we call chasing. this is where we effectively cut channels out in the walls to allow cables to be installed. If proper techniques are not used at this stage it can produce extreme amounts of dust, chasing machines with dust extraction systems can greatly reduce the dust produced at this stage so make sure your contractor is using them, as the dust that comes from cutting into brickwork contains silicates which are harmful to health if breathed in. After chasing out we like to make sure that all rubble produced is removed promptly and the property is left clean and tidy.
So now we come to running cabling. this involves folding back carpets where necessary and lifting floorboards. we then use a variety of techniques to feed the cabling through to all of the sockets lights and switches whilst making sure the cables do not get damaged in the process.
Once all of the cables have been run into place we then make sure all cables are securely fixed into place and all cables run in channels in the walls are protected by capping or conduit so that when the channels are filled or plastered the cables do not get damaged in the process. We make sure all of the back boxes are securely fixed in place and then we double check to make sure that all of the cables required are in place and in good condition before the walls are made good again.
The making good stage is the process of making sure all floorboards are securely re-fixed. Carpets laid back in place and the property is cleaned and tidied up. At this point you are ready for the channels in the walls to be filled. this will usually be done by a separate plastering contractor but some electrical contractors can provide this service. Once this stage has been completed you are ready for the second fix.
This is where the magic happens. At this stage all of your new sockets switches and light fittings are installed. again for a normal 3 bedroom house you can expect between 1-3 days for this process.
I like to start off by getting the new consumer unit (fuse board) fitted. then move on to getting all of the lights and switches installed throughout the property before dropping back and fitting all of the sockets.
Testing and commissioning
This is probably the most important part of the entire process. this is the part where years of experience come into play and we fully inspect the new installation and use specialist testing equipment to verify that the cabling has not been damaged in the process of installation and that all of the connections are sound.
We start off with dead testing. This is carried out with the electric in the property still turned off. We confirm that the continuity of all the cables are good, make sure that the insulation around the cables has not been damaged and we visually check the installation to make sure everything is safe to energise.
The Installation is energised and we commence with live testing. This process involves using our test equipment to prove that there is a good earth path to all of the accessories and that the protective devices in your consumer unit will trip within the times prescribed by BS7671 (the electrical regulations).
Our results will be recorded on an EIC (Electrical Installation certificate) which will be issued to the person ordering the work on completion of the job. and in England and Wales the job will then be notified to the local authorities building control through a part P scheme provider such as NICEIC, NAPIT, ELECSA and STROMA. Please make sure the contractor you use is registered and insured as not having the building control compliance certificate can cause problems in the future when trying to sell your home ETC