What is a consumer unit?

1) So there is a box somewhere in everybody’s home. It contains all the components that protect the wiring in your home and keeps you safe.

There are normally switches in this box just like the photograph above. If you find yourself asking What is a consumer unit? Then keep reading, I can put you to sleep in no time at all! 😊

The consumer unit carries out a few different functions depending on how modern it is, how well installed is it and how well designed the circuits are, some of these functions are listed here:

• Protects your cabling in your home from overload, fire and excessive power being used beyond what the cables can handle safely.
• Protects you and your family from electric shock to varying extent.
• Protects your wiring and home appliances from surge currents, nearby lighting strikes causing high voltages and spikes.
• Can protect against electrical fires caused by arcing or sparking.
• Can disconnect wiring in the event of a fault.

2) Does it really do all that?

Yes and no. If your consumer unit is brand new and up to date with the latest regulations then it will certainly be able to perform lots of those tasks. There are certain functions that a consumer unit wont perform if it is particularly old or if a budget consumer unit has been installed then certain features may be missing. We are able to install a consumer unit that can, to a great extent carry out most or all of the above functions. The consumer unit is the BRAINS of the electrical system and is able to protect the installation.

3) What about the old style consumer unit with wire in the fuses?

These units are obsolete now and the last type would have been installed around 40 years ago or more. These consumer units are still in lots of homes across the UK and still in operation. In fact, many of these units may carry on giving useful service for many years to come but that doesn’t mean they are the absolute safest and best available. These older style units may be missing key features such as Additional Protection against electric shock, Surge protection to protect wiring and so on. If we consider a motor vehicle from around 40 years ago and compare it to its modern day counterpart then there are key safety features in a car that we would not be without today.

Don’t run away with the idea that these consumer units are completely fine though, there may be hidden issues that these units miss. Wiring can decay in walls, circuits can have dangerous problems and these older consumer units will not pick up on these issues. We would always recommend that if you have one of these units then you strongly consider having an electrical inspection carried out on the electrical installation in your home. This article What is a consumer unit? Should give you all the answers you need, if you have more questions then feel free to use our contact form and we will do our best to help you.

4) What is an electrical inspection?

Briefly, it is a Periodic Electrical Inspection that will let you know if there are any dangerous issues with the wiring or electrical installation in your home.  A document is produced from the inspection called an “Electrical Installation Condition Report” which will list any problems that require attention or any recommendations for improvements in the wiring installation. The document is around 6 to 8 pages normally and can look very technical. A good electrician will be able to break it down and explain it for you in plain English.

There are a number of other articles / blogs on our website relating to EICR and Electrical Inspections, an example can be found here.

5) What are those switches inside my consumer unit?

There are different styles of switches in your consumer unit that carry out different functions. These are explained below.

• Main Switch: This disconnects the electrical supply to your consumer unit all in one go. This removed power to the box and all the other switches in the box.
• MCB: Circuit breakers. These will control different bits of wiring in different parts of your home. If a switch is labelled cooker then is should (not always) control the cooker circuit and the power to that circuit.
• RCD: Residual Current Device. This clever device has been around for 100 years or so. This device prevents the users of the electrical installation from having a fatal electric shock. It is still possible to get an electric shock if you have these installed so don’t try licking live wires!!! The point is that these devices will limit the severity of shock if installed correctly and of the correct type.
• RCBO: A type of RCD that not only has the electric shock protection but also protection against overloading (too much power being demanded on a circuit).

There are other types of devices that may be installed in your consumer unit but these are the most common types. They each have their own purpose and when the consumer unit has been designed and installed correctly by your electrician then everything will work to protect you and your wiring from harm.

6) My consumer unit is plastic, does it need replacing?

No, not at all. Simply because the unit is plastic does not mean that it needs replacing. Nearly all modern consumer units now are constructed of metal as this has come about due to a change in regulations. If your consumer unit has any of the following issues then we recommend that you have it checked:

• Signs of melting, browning, thermal damage.
• Holes large enough to put a finger in (please don’t try this).
• Almost any sized hole on the top surface.
• Gaps in the front where switches should be.
• No cover on the unit.
• An out of date inspection sticker or no inspection sticker at all.

If you are not sure of any of these point above or find yourself asking, What is a consumer unit, just get in touch and we will try to help. We like to offer our customers free impartial advice so that they are reassured or are able to make an informed decision.

7) My consumer unit trips sometimes is this normal?

No, it's not. If this happens more than once a month then you really should have it checked out. The best time to have this checked out is if the consumer unit is tripping more than once a week. If you can, get an electrician out immediately after this has happened. There is another article on our site under the help sheets section just here: https://www.electricalfaultsfixed.co.uk/helpsheet/help-my-house-electrics-are-tripping Which will help you try and eliminate the need for us to come out. The help sheet has been written by us to enable you to do some investigative work without our help.

8) When should I have my consumer unit replaced? Do they last forever?

There are times when a consumer unit replacement may be absolutely necessary. There is a great big book of wiring regulations that all electricians need to follow in order to abide by the law and to keep our customers safe. The big book of wiring regulations states many different things but as a summary you should consider, or may need to have your consumer unit replaced if any of the following were to happen:

• New kitchen installation, new appliances, wiring moved around.
• Extending the property including new wiring.
• Rewiring the property.
• New bathroom and circuits to bathroom.

The list above is not particularly extensive and does not cover every scenario. It may also not be necessary to replace the consumer unit if it is modern enough. The best way to know for sure is to contact a trusted local electrician and ask for some advice. We have written another help sheet on this (we know, we are too good to you) and it can be found here: https://www.electricalfaultsfixed.co.uk/helpsheet/why-does-my-fusebox-need-replacing

If you have managed to stay awake for this whole article then well done. If like us you really enjoy electrical information and would like to know more, then stick around the website and have an explore. If you have questions that you need answers to then feel free to use our contact form and one of us will get back to you.