Consumer unit replacements

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. 

A modern consumer unit contains devices such as MCB (Miniature Circuit Breakers), RCCB (Residual Current Circuit breakers), RCBO (Residual Current Circuit Breaker with Overcurrent Protection), SPD (Surge Protection Devices), AFD (Arc-fault Protection Devices). It’s also often (but not always) the place where you or perhaps an emergency services crew, need good and fast to access to in order to turn off power to your property.
 

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 (and second amendment of that). 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. 

Circuit breakers are fitted to all household circuits and protect the wiring (and to a lesser extent, you), mostly from overheat and fire in the event of faults. 

RCD’s are fitted to nearly 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 be 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. 

RCD devices come in different types. Up till recently, a common (and nowadays almost obsolete) RCD type, was called type “AC”. Very widely employed and found in millions of UK properties today, these are not recommended for installations containing motor-drives (example, your fridge/washing machine) or extensive IT equipment (example, your computers/TV’s etc). These older devices are also most unsuitable for EV chargers and heat-pumps etc. 

Also, many existing and even new budget-installations tend to have featured typically just two RCD devices in one consumer unit, each supporting a bank of several circuits. This elderly style of consumer unit (still sold and fitted today) is the reason for “half the house” switching off if there is a single fault. I will generally never fit these, and instead, always offer you an “all RCBO” installation, containing “type A” RCD devices, one for each individual circuit.
You might find aforementioned budget consumer units are offered and still quoted by other installers, so it is worth enquiring WHAT they intend to fit should you be comparing quotations. You can find more information about RCD's here.

Other new 2018 introductions are requirements for SPD (Surge Protection Devices) in all domestic installations. If I fit a new consumer unit, I’d frequently include the SPD within the new unit, but it might also be better fitted at the supply “head” where the power comes into your property. It might also be needed to protect cables which run OUT of your property (for example to garden, shed, garage, and outbuilding if these are a long way off). 

Certain conditions also recommend AFD (Arc Fault Detection) devices which for selected types of household circuits. 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. AFD will help reduce the incidence of house fires caused by wiring or faulty appliances. Currently AFD is not commonly used or fitted much in domestic properties, but prices are coming down and its performance has been improving. I can offer AFD’s as an option and you might decide to take that up for certain circuits, but it will add significantly to the cost and reduce the options I have to choose better value equipment. 

Should you wish to “future proof” your installation, that is another reason for me to recommend a quality brand “all RCBO” consumer unit, as noted previously, from which the manufacturer is more likely to support retro-fit of AFD into the future. 

As our houses become more electrified, the loading on a consumer unit increases, leading to more internal heat dissipation from the cables and devices within. Where space is tight and where you need new heavy loads (induction cooking appliances, car chargers, heat pumps etc), then you might need to look further then the "one spare slot" you perhaps have already. There could be examples where I'm looking for THREE spare slots to accommodate certain heavy duty circuits safely. 

Another reason for me to recommend a quality-brand consumer unit is the likelihood of you requiring an Electric Vehicle (EV) charger now or in the future. This is a market that’s technically changing fast, and at the moment, some existing EV charger types still need specialist RCD devices which might not be available from a budget-brand consumer unit manufacturer. 

All new consumer units within properties must be fireproof and typically made of steel (not plastic).

​If you would like me to add new circuits (for example, new wiring for lights, sockets, anything really), to your house, Regulations mean that some of these requirements must be in place.  

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. 

Replacing a consumer unit typically takes me two days as a minimum, even if your property is relatively compact. Upgrade means I must inspect and test ALL of your household circuits and to end. I frequently also need update the earthing and the "Bonding" in addition to fitting the 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 some 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.