subject: Changing A Consumer Unit [print this page] Updating an aged consumer unit to one incorporating two residual current systems, RCDs is a activity that many people today will currently have to think about. The 17th edition of the cabling legislation requires most circuits in a home property or home to be guarded by an RCD. It is normally a better and less costly option to improve the consumer unit preferably than adjust the current set up in order to comply with the new rules.
A consumer unit using rewireable BS 3036 fuse carriers was upgraded to a Seventeenth edition split load board making use of signal breakers occasionally referred to as MCBs, miniture circuit breakers. The circuits on the new consumer units are protected by two residual current devices. Power and lighting circuits for the same floor are split between the RCDs on different sides of the board. This is so that in the event of a fault all the circuits on a particular floor are not cut-off from the supply.
Consumer unit to be improved with fuse carriers taken out
17th edition electrical wiring restrictions related to consumer units
The new wiring regulations launched in 2008 request that all circuits are safeguarded by RCDs. Often the simplest way to conform, particularly if the current fuse box is outdated, is to update.
Changing the consumer unit may also include some supplemental electrical work, to allow the unit installation to fulfill the expectations set by the new wiring rules. This might include splitting circuits or running in new cable. An older property might have all the lighting and sockets delivered by just two circuits. It would be better practice to divide these so that the lighting and sockets for each floor are on different circuits with their own circuit breaker. Additional complications that require consideration include borrowed neutrals. This is where a neutral return route was not available and a link to an additional circuit has been crafted. Correcting this error would, in many instances, will need a new cable to be laid back to the consumer unit.
Old consumer unit taken out and taking away out of date wires
Taking a look at earthing and bonding arrangements
Just before the consumer unit is changed, the electrical contractor will have checked out the distributor's equipment at the starting point of the installation and the earthing and bonding arrangements. This is to make certain that they are reliable and that they conform with the laws. A large number of older properties do not have a dual pole isolation button between the meter and the consumer unit meaning that the electrical manufacturer will have to be called in before work on the consumer unit can get started. The provider may help by setting up this main switch.
The majority of domestic premises have the following arrangement at the source: the service cable going into a sealed unit with a fused line (live) conductor with a 100amp main fuse or service cut-out, 25mm meter tails, a digital or analogue meter, 25mm tails to consumer unit. It is here that the primary switch would be located. The programmed disconnection of supply' would be provided for by 16mm earthing conductor and 10mm main bonding conductors to gas, water and other services. These arrangements vary with larger or smaller sized installs; your electrician will guide you on what is necessary.
Fitting wall support
Creating first connections to 17th edition RCD board
Installing the new consumer unit
The dynamics of this work, disconnecting the overload protection and attaching the wire to a new means of basic and fault protection means that the electrical installer will have worked on all circuits. He will for that reason have to perform an electrical test on all circuits to make sure that they are secure and will then have to issue an electrical installation certificate before the job is passed over. Any flaws identified on a circuit will have to be remedied before the circuit is energised.
Setting up circuit connections
New consumer unit in place prepared for labelling
Safety Note
Just before any work is carried out on an electrical circuit, the circuit must be separated and locked off or the fuse carrier removed. A sign must be placed at the isolation point saying that work is being carried out and that electric power must not be returned to the circuit.
If you are not 100% certain that you know exactly what you are doing call in a competent electrician. Building policies are getting stricter, necessitating that competent individuals only carry out electrical work, with most works having to be informed to the local authority. Changing the electrical installation in your house could be in opposition to the new rules and could invalidate your home insurance plan, if in question check first!
Electrician in Gloucester
Suite E 21 The Plantation, Hardwicke, Gloucester GL2 4SP 0845 094 3843 http://www.electricianingloucester.co.uk
