Circuit Board Installations

A consumer unit, also known as a fuse board or electrical fuse box, distributes electricity from the mains supply to individual circuits around a property. The mains power, having passed through the electrical meter, then gets distributed to the different electrical circuits in the building, and hence the electrical accessories e.g. sockets, lights etc. Getting the right consumer unit for your needs and the application is very important. We are here to help you get the right consumer unit, to understand how it works and are very happy to install it for you. 

 

Fitting a new consumer can be quite an involved job, where the power needs to be switched off for a few hours and each circuit connected to its relevant protective device. Both before and after powering up, thorough electrical testing is carried out and recorded as an Electrical Installation Certificate. This is presented to the customer on completion of the job and also submitted to building control. That is why it is imperative the installing of the consumer unit is carried out by a competent electrician.

 

When to replace a consumer unit?

 

Every house will have either an old-fashioned fuse board or a consumer unit as the place where circuits are protected (with fuses or MCBs (Miniature Circuit Breakers) and can be isolated (i.e. turned off). So, when to change a consumer unit? Why upgrade the consumer unit? If the old one has worked up until now why change it? There are a number of factors to consider:

 

• It may be that you have had an electrical installation condition report carried out and the report has recommended that the consumer unit/fuse board be replaced. If you are unsure why you can discuss this with the electrician who carried out the electrical test and inspection. 

 

• If you have a fuse board (ie. the circuits are protected with fuse wire rather than MCBs) then there are some important differences consumer unit vs fuse box that you should be aware of.

Regarding fuse boxes:

 

• The type of circuit overload protection will have longer disconnection times. What that means is, if there is too much current being drawn on a circuit (may be too many electric heaters are on one circuit) then the fuse wire will blow (or MCB trip off) in order to protect the cable from overheating and eventually melting. 

 

• There is likely to be no RCD (Residual Current Device) protection on a fuse board – more on this later. This means you and your family are more susceptible to an electric shock in the event of an electrical fault. The fuse (or MCB) will protect the cable, however, the RCD will protect you should you touch a live part of the installation. In that event, you become a part of the electrical circuit and some current flows through you to earth. This creates an imbalance in the current which has flowed out from the supply compared to what has flowed back. The RCD picks up this imbalance and trips off.
  
  Some old fuse boards may have an old-fashioned earth leakage device sited before the fuse board. However, these will not meet the higher modern standards and best replaced. They deteriorate over the years and don’t trip off in the required time. 

 

• If you have built a new garage, shed or outhouse you will need a new consumer for that building. The same will most likely be true for building an annex or extension on your house. It is always more preferable to run in one new supply cable to the new area and feed new circuits out from there, rather than extend a number of existing circuits to the new areas.

 

There are occasions where you are already have a consumer unit (i.e. MCBs) and it’s still appropriate to ask the question, why upgrade the consumer unit? Here’s some reasons:

 

• The consumer unit may not have enough ‘ways’ to accommodate some new circuits being added to the installation.

• The MCBs may be very old and deteriorating.

• There may be no RCD protection on the consumer unit.

• The consumer unit may be damaged, not be securely fixed or have an inappropriate IP rating (i.e. large holes allowing possible electric shock for prying fingers).

• You are having new circuits run in the house and want to be sure all the associated electrical installation is new and complies with the latest regulations.

• For some older consumer units if you require a new circuit breaker (MCB) or a RCBO (residual current breaker with over-current) the manufacturers sometime charge an exorbitant amount to make it more cost effective to replace the whole consumer unit. Which, to be honest, is the better option for you.