follow me on twitter



Find Circitas on Elecsa website
Electrical supply head TN-S

Consumer Units or Fuse Boards

An old Bakelite Consumer Unit

If you have one of these on your wall, you will probably need an upgrade before I can do any work on your wiring. For your own personal safety you might also be interested in an upgrade!

MK Consumer Unit
Wylex Consumer Unit

Is your Consumer Unit (Fuse Board) safe?

​Your home Consumer Unit (AKA Fuse Board, Fuse Box, Distribution Board) is where the electricity supply meets your home circuits. It contains ways to make you and your house safe. It does this by helping to protect you from dangerous electric shocks, and to limit the heat which could build up in faulty wiring which can lead to damage or fires. 

UK electrical installations need to meet BS7671 "Requirements for Electrical Installations"  which is the documentary starting point for all work and reviews of existing installations. These requirements have been regularly updated since the first edition dated 1882. The Regulations are now in their 18th edition. Recent years have seen significant changes which improve the safety of the installation in your property. These broadly cover fire risk and ways to improve electrical safety for you, your home, and equipment in it. - For example, from 2018, Residual Current Device (RCD) protection will be needed prior to works on pretty much EVERY circuit on your house. (Previously we had a few let-outs which are mostly now closed off to us). 

RCD’s are fitted to all household circuits and they monitor the "leakage" current in your circuits, ready to break the supply extremely quickly to prevent a harmful electric shock if they detect a fault to earth. - A fault which, for example, might caused by certain types of damage or deterioration in your wiring, or it might be caused by you receiving an electric shock. An electric shock in the absence of RCD protection is much more likely to be damaging or fatal ! This is the case even for old existing installations which met the safety regulations that were in place before RCD's became a requirement. You can find more information about RCD's here.

Other new 2018 introductions have caused considerable discussion in the Industry. These are recent requirements for SPD (Surge Protection Devices) in nearly all domestic installations (omitted only by soundly backed up risk analysis which stacks very strongly in favour of the devices), and also for AFD (Arc Fault Detection) devices which are recommended for selected household circuits. These, compared to what would have been typically fitted the previous year, all require hardware alterations (and additional parts  which aren't cheap). Like all new changes, these alterations will also take some time to settle-in, whilst manufacturers are scrambling to manufacture and make available new devices to satisfy the market.

The Surge Protection will be mostly fitted at the supply “head” where the power comes into your property. It will probably also be needed wherever cables run OUT of your property (for example to garden, shed, garage, outbuilding).

The Arc Fault Detection will protect your installation against the threat of burning arcs which can reach 5000 degrees C and might come about in your household wiring as a result of poor connections/wiring breaks combined with heavy load. ADF will help reduce the incidence of house fires caused by wiring or faulty appliances.  Both SPD and AFD might, or might be fitted either inside or in addition to your consumer unit. - The decision depends entirely on the circumstances.  

​If you would like me to add new circuits ( for example, new wiring for lights, sockets, anything really), to your house, Regulations mean that you must have RCD protection and some other important safety measures (such as your "Bonding") in place. It may also be the case that I need to make a design decision based on the 2018 requirement for Surge Protection Devices and Arc Fault detecting devices (see above). One of the best ways to bring your system to an acceptable standard to add new work, where you now have an old Consumer Unit is to first get that upgraded. This typically takes me two days since it means I must inspect and test ALL of your household circuits, and frequently update the earthing and the "Bonding" in addition to fitting a new the Consumer Unit and other ancillary parts.

Whilst I'm doing all that work, it's very common (and from practical experience.. nearly always), that I uncover faults in your wiring which I need to fix. I'll put right the small things as I test, whilst working my way through your property.  If I find bigger problems, then sometimes we do need to take a view on it. 

- The types of faults I can typically find when I inspect and test for a new Consumer Unit in old houses are varied. For example, poor original workmanship  resulting in exposed or vulnerable joints, open circuit cables, high resistance junctions, sockets or switches,  inaccessible & faulty junction boxes, inadequate bonding, dangerous lack of earthing, incorrect cable rating, water damage to cables, rodent damage. Old DIY wiring alterations can be a particular fruitful source of imaginative bodges. 

Bakelite Consumer Unit Fuse Board
BS7671 electrical wiring standards

What is involved when I swap your consumer unit?

Prior to replacement I need to ensure that all your household circuits are adequately safe and in good enough condition for me to take "ownership" of he safety and to connect them into a new unit. This nearly always requires a considerable amount of investigation and testing throughout your property before I take any parts away from your old installation. This pre-test can often take an entire day even in a relatively compact house, so please make allowances when you are planning for this work and the potential costs. Some videos of this going on are at Consumer unit work and here  .

Your electricity Supply

Making these Consumer Unit upgrades, I will also take a hard look at your electricity supply, the Earthing and the "Bonding" and the connections to your electricity meter. It's surprising how many old properties have potentially dangerous supply problems. Despite the spiders, this one turned out to be fine. 


BG Consumer Unit

So "Why do I need a new Consumer Unit?" 

Consumer Unit
Circitas Ltd
follow me on facebook
Circitas is a Registered Competent Person Electrical