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 Do I need to re-wire the house?

·         The electrical installation an every house will degrade over time. Switches wear out through use, plastics on switch plates, sockets and light fittings become brittle or discoloured through exposure to sunlight, or heat. The rubber insulation on old black rubber sheathed cables may crumble away (just like those old rubber bands lurking in the bottom of the draw), especially where exposed bright sunlight, or just to air behind switches and sockets, in floor voids, etc. The even older lead sheathed cables with internal rubber insulated cores suffer from similar problems. This can lead to short circuits, blowing fuses, and more seriously a risk of electrocution and fire.

·         Since the 1960’s PVC insulated cables (grey or white sheaths) have generally been used. In many cases these continue to give good service, but their lifetime may be degraded by exposure to sunlight, or excessive heat from overloading or being covered by loft insulation.
      A comparatively rare problem is "Green Goo". If you encounter a sticky oily green substance dribbling out of your sockets, switches or light fitting then it may not be a bad case of poltergeists!
This is a problem for PVC cables manufactured by one of the large UK cable companies between 1965 and 1971. The story goes that they altered the formulation of the PVC insulation to improve its temperature rating. Unfortunately this new formula resulted in the PVC plasticiser (di-isoctyl phthalate) being slowly exuded from the plastic. This then reacts with the copper wire to form the green goo. The process is speeded up if the cable is exposed to higher temperatures. There is no cure and will usually require a rewire. The extrude is generally considered to be of low toxicity and low flammability, but for safety it is best to avoid skin contact or ingestion.

·         If you have a fuse box with old style rewireable fuses, especially those in ceramic carriers, then this is an indication of the advanced age of the rest of the installation. Note however that the fuse box may have been upgraded at some time in the past, so look at the wiring and other fittings as well. Round pin sockets and fittings mounted on wooden blocks are sure indicators of an old installation.

·         Many defects to fittings will be obvious to even the untrained eye. Don’t ignore them! Get them fixed before they cause a problem. It is currently recommended that typical domestic installations are professionally inspected at least once every 10 years to check for these and other hidden defects.

·         Advances in technology and home appliances mean that there are now may more items of electrical equipment in the home. A common problem is having insufficient sockets to plug all this stuff into. This leads to the excessive and potentially dangerous use of multi-plug adaptors and extension leads. See How many sockets for current recommendations. A rewire will allow a general upgrade in this area. (But note that additional sockets can usually be added to an existing circuit, or a new socket circuit can be added, subject to certain constraints).

·         Also note that the “Wiring Regulations” (British Standard BS7671) have been updated many times to keep track of advances in safety technology, and to incorporate lessons learned from past problems. While there is no obligation for a home owner to upgrade their installation to the current standard, a rewire will deliver this, leading to a safer installation.

·         It may be possible to upgrade an older installation with PVC cable by just replacing the fuse box with a modern type incorporating MCBs and RCDs. If you currently have no RCD this will give a significant safety benefit.

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Ring & Radial, 47 Park Lane, West Grinstead, Horsham, West Sussex, RH13 8LT