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JD Electrics brief overview on Fuse boards / Consumer units


What is the difference between a fuse box and an electrical consumer unit?


A fuse box and a consumer unit serve the same purpose. They distribute electricity in your house through multiple circuits and instantly turn the power off whenever a power overload occurs on one of the circuits, which is commonly known as “tripping”. 

When “tripping” occurs, a consumer unit will switch the power off using the circuit breaker linked to the overloaded circuit. It will turn itself to the position OFF making the faulty circuit easily identifiable. Once the circuit is fixed, the circuit breaker can be switched back on and the power restored.

A fuse box uses fuses instead of circuit breakers. Each fuse contains a wire which will melt if there is an electrical overload and make the circuit trip and switch the power off.


It is not as easy to identify a faulty circuit when using a fuse box and the, now melted fuse, will need to be replaced before the power can be restored.
Consumer units are basically the modern and safer version of fuse boxes which in most cases are no longer compliant with current electrical regulations.
If your house is fitted with an old fuse box, it might be time to for you to replace it.

How do I know if I have an old-fashioned fuse box?


It’s very easy to tell if you have an old-style fuse box or a more modern consumer unit.

An old-style fuse box will have a series of fuses contained inside fuse carrier which you can manually remove and replace when one of them goes off following a power overload.


The two pictures below shows typical old style rewirable fuse boxes  



A consumer unit however, will be made of a horizontal row of what is known as MCB (Mini circuit breakers).

Each MCB will have a switch which can go off in case of a power surge.

The picture below shows a standard plastic dual RCD consumer unit



Main switch Consumer Unit

This type of consumer unit only has one main switch from which all circuits in the house can be switched off.
In case of a power surge the main switch will trigger itself to the position off, along with the toggle of the faulty circuit.
This is a very popular choice, especially for single storey houses and small flats. These circuit breakers are rcbo's with their own trip switch

Berkshire Consumer Unit

Dual RCD Consumer unit

A dual RCD (residual current device) consumer Unit offers the ability to split load the power over two sets of circuits, RCD1 and RCD2.
The advantage of this consumer unit is that it is possible to alternate the circuits so the power can still be available in some part of the house if one of the RCDs is no longer operational. This is ideal for multiple storey houses.

 Consumer Unit Reading


High integrity Consumer unit

High Integrity consumer unit have become a very popular choice over time as they offer the ability to separate all circuits independently. So while your freezer may stop working, everything else will continue working without interruption.

Electrician Consumer unit

How much does it cost to replace a fuse box or electrical consumer unit?

The costs of replacing a fuse box or upgrading a consumer unit to a more recent once can vary greatly as it will depend on many factors such as:

It is best to contact JD Electrics first for a free quote.

A typical replacement ten way RCD Consumer Unit (Labour and part) will cost between £550 and £650 and will include:


The quote in this example does not include the earth & bonding check which need to be carried out before the replacement takes place. The Earth and bonding inspection will establish if there are any fault in the existing installation which need to be addressed before the fuse box can be replaced


Installing Rcbo’s is an additional cost. These circuit breakers have their own rcd trip switch. They only trip one circuit. They are ideal for outside power because they do not cause nuisance trips with other circuits


Do you think it's time to replace your old fuse box?
Call JD Electrics for your FREE quote

07884 065 057 

Can I replace my fuse box myself?

Electric installation such as the replacement of a fuse box should be done by qualified individuals who are able to issue a certificate for the installation in accordance with Building regulations. In this instance a qualified electrician is your best option


Where to install consumer unit?

The location of where your consumer unit should be installed is often overlooked. Since they are not considered as a feature of a house, consumer units are frequently hidden away in some dark place in a house. Consumer units should be located so they can easily be reached whenever it is necessary so it is in compliance with Part M of the building regulations. They ideally should be mounted with the switches at a height of between 0.45m & 1.2m above floor level.



Can consumer unit be boxed in?

Consumer units boxed in wooden cupboard or mounted under wooden stairs are seen as a fire hazard as these materials are highly combustible.
According to BS7671 Wiring Regulations 2019 18th Edition your consumer unit should be enclosed in a cabinet or enclosure constructed of non-combustible material such as steel.


Can I have a consumer unit in my bathroom?

According to regulations, electrical equipment should not be present in shower rooms or bathroom. This includes simple equipment such as wall switches, plugs and especially consumer units.


Is it dangerous to install a consumer unit near gas meter?

According to regulation, gas pipes and gas meter in domestic houses, must be spaced at least 150mm from electricity meters, switchboards, electric cables, sockets, telecommunication cables, consumer units and any other conductors. Additionally, there should be a separation between a supply or distribution cable of at least 25mm for domestic pipework up to 35mm or 50mm for pipework over 35mm.

How long does replacing a fuse box take?

The time it takes to replace a fuse box may vary on the size of the property as well as the condition of the existing wiring. A typical replacement generally takes 1 or 2 days including testing / bonding.



Do you think it's time to replace your old fuse box?
Call JD Electrics for your FREE quote


07884 065 057