What is a Consumer Unit?
In simple terms a Consumer Unit is a device that provides a means of connecting the incoming Electricity Supply to the wiring in your house. Depending on the age of your Consumer Unit, it will also contain various safety/protection devices. Older equipment typically use fuse wire or cartridge fuses to protect the circuits in the event of a fault. These can be unreliable and are inconvenient to change should the need arise. Modern equipment uses electronic safety devices (MCBs) which as well as being more reliable, are far more convenient as they can simply be reset with the push of a button (once any fault has been rectified). Also worth mentioning are RCDs which are present in all modern Consumer Units. Again in simple terms, these devices monitor the electrical circuits in your house and if they detect an imbalance caused by a fault, they disconnect the supply almost instantaneously.
Do I need to replace my consumer unit?
For peace of mind it is advisable to seek out a Registered Electrician and discuss your concerns. If you own your own property and have not had an Electrical Installation Condition Report carried out in the last ten years then one should be carried out as soon as possible. Your Electrician will then be able to advise you on the condition of your entire installation and advise you of any remedial work that needs carrying out including improvements to your Consumer Unit. Should you decide you wish to replace your old Consumer Unit, your Electrician will chose which size and type of protection devices to be used based on a number of factors such as cable size, the load which is to be placed on each circuit and the type of circuit. He will make these decisions based on a visual inspection as well as tests made using specialist test equipment. Also worth mentioning, modern Consumer Units offer the ability for your Electrician to update and modify the installation in the future without having to replace it. Therefore when discussing your needs it is always a good idea to specify that you require extra space on the Consumer Unit to accommodate this facility.
Below is a picture of a modern Domestic Consumer Unit:
Below are a couple of pictures of older Consumer Units. Also in particularly old boards it is not uncommon to find they are made at least partially from wood. Of course nowadays this would be considered a fire risk and would not be acceptable in any kind of electrical installation.
How much does a new Consumer Unit cost?
Prices vary depending on many factors, the most obvious being the size of the installation. Due to the large amount of testing that needs to be done on every circuit, the size of the property (and amount of circuits) plays a large part in this. Other factors which can affect price include night storage heaters, solar panel (PV) installations and the supply of power to outbuildings. Also other upgrades may be required such as improvements to your bonding or earthing conductors.
We have found that 90% of installations can be carried out for between £400.00 and £800.00 inclusive of parts and labour. Very small installations may come in less and of course the opposite is true of larger installations. A reputable electrician should be happy to offer you a free consultation to discuss your needs.
The law and you.
It is a legal requirement under “Part P of the Building Regulations” that any electrician who installs a new Consumer Unit is registered with a Part P compliant scheme operator such as ELECSA, NAPIT or NICEIC which have strict membership requirements.
It is possible to carry out Notifiable works without the services of a registered electrician but you will need to consult Building Control throughout the process and they will charge you to have the installation tested by one of their Electricians which can cost a considerable amount. If the installation fails for any reason Building Control will insist it is brought up to standard and may charge for an additional visit to verify this has been done.
Damage caused by the incorrect selection of cables and MCBs can result in fire and an increased risk of electric shock. Therefore it is imperative that you employ the services of a highly trained and qualified Electrician to install or carry out maintenance on your Consumer Unit.
Your chosen Electrician will be obliged by law to notify building control on your behalf of the work that they have carried out. Your Electrician should NOT attempt to make any significant additional charges for doing this as it is a legal requirement of carrying out this work.
The selection of protective devices (MCBs/RCDs and RCBOs) and cables are dependent on the earthing arrangement in your property. There is no one size fits all solution when choosing a Consumer Unit which is why it is so important that you select a tradesman with the correct training and equipment to make these decisions. It cannot be stressed enough that regardless of law this is not a DIY job. The implications of making the wrong choices when installing a new Consumer Unit or circuit can be catastrophic.
This article was written by SG Electrics of Leigh On Sea, Essex in the UK and makes reference to British legislation specifically BS7671.
We are trusted Electricians who specialize in domestic installations. We are happy to give free advice and no obligation quotes anywhere in Southeast Essex. We carry out all works including new Consumer Units, rewires, fault finding, Electrical Installation Condition Reports and Landlord Services. SG Electrics are members of ELECSA (part of the ECA group) and as such are able to notify all work to building control on your behalf at no extra cost.
© Samuel Green and SG Electrics, 2015. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Samuel Green and SG Electrics with appropriate and specific direction to the original content.