How Long It Takes To Replace A Fuse Box (Consumer Unit Change)

Whenever I visit a customer’s home to discuss a fuse box/consumer unit change, I notice the majority of questions they have are usually around the subject of how long a replacement fuse box will take. This is completely understandable. With so many more people working from home, and all the electronic devices we now rely on, the idea of having the electricity switched off during a fuse box change is unsettling.

In this post, I have polled electricians and collected information to give an overall picture of the timescales required to replace a fuse box. At times I’ll chip in with my own opinion but I was interested to research the topic myself and find out if I was slow or fast when it comes to changing a fuse box/consumer unit.

Switching on an MCB in a new consumer unit
Switching on an MCB in a new consumer unit

Here is a brief summary of what I discovered:

We polled other electricians to discover the average time it takes to replace a fuse box/consumer unit and these are the results:

  • The majority of electricians (61%) said they average between 6 – 8 hours to change a fuse box
  • 30% of electricians said they average 4 – 6 hours
  • 9% of electricians said they average more than 8 hours
  • 0 electricians said they could change a fuse box in less than 4 hours

A quick note: For the purposes of this article I shall refer to it as a fuse box as I think this is the most common name customers use. Its more technically correct name is consumer unit or distribution board, but I try my best to stick to jargon-free language on this site.

Below is a table of results from the poll I conducted to find out the average time electricians take to replace a fuse box in a customer’s home.

Electricians Asked the Question, How Long Does it Take to Replace a Consumer Unit (Fuse Box)?

Time Estimated
Number of Electricians
0 – 20
Over 82
Table demonstrating electricians response to the question, how long does it take to replace a fuse box (consumer unit)

We can see from the results that when we are having a fuse box replaced we can expect the electrician to be working in our home for at least 4 hours but more likely it will be at least 6 hours.

These times are a great starting point to now look at the different factors that affect timescale to discover if there’s anything we can do to speed the process along.

Is Changing A Fuse Box Hard?

Changing a fuse box/consumer unit is not usually a hard job for an electrician as it is a relatively straightforward task. The difficult part is ensuring that the new consumer unit (and all the electrical circuits) now comply with the latest edition of the BS7671 regulations.

I find it helps to explain to customers that generally it is not the change of the fuse box itself that is hard but the complying with the regulations. The consumer unit can be replaced in a matter of 2-3 hours if it is an almost like for like replacement.

Sometimes combining multiple old fuse boxes into one new consumer unit makes the task a bit harder. However, this is something an electrician can judge pretty accurately by looking at the existing fuse box and its surroundings before beginning the work.

If they do need to chase walls, or re-plastering is needed after the work, (do electricians plaster article linked here) they will be able to advise when quoting for the work.

What Can Make a Fuse Box or Consumer Unit Change Take Longer?

The reason that a fuse box change (consumer unit change) may take longer than expected is if problems are found with the electrical circuits during testing. Electricians have regulations they must adhere to, and getting old circuits in old houses to comply with the latest regulations can be tricky.

We don’t want to get too into the weeds discussing regulations in this article, but a brief look will hopefully help a customer to understand why giving an exact timescale for replacing a fuse box is difficult.

As electricians, once we make alterations to an electrical circuit, we have now taken responsibility for that circuit. In order for us to get a pass on the test certificate and to ‘sign the work off’ as complete, the circuits must now comply with the latest regulations.

There can be a surprising amount of work in old houses to bring the old electrical circuits up to the latest regs. It can be a simple case of changing a plug socket or could be the earth bonding which is one of the most common tricky to fix faults in old houses. You may have heard electricians talking of bonding so it’s worth a quick look.

Why Does My Electrician Talk about Bonding During a Fuse Box Change?

An example of bonding in a house
An example of bonding in a house

Bonding is the practice of running an earth cable from the fuse box/consumer unit to the service pipes (water pipe, gas pipe etc) as they enter the house. This entry point is often under the sink.

When an electrician needs to ‘upgrade the bonding’ they are referencing the fact that the new regulations increased the size of the earth cable required.

As we have seen, if we change a fuse box we must now bring the whole electrical installation within the home up to the latest regulation standards, this includes the bonding.

In an old house, the earth cable that is used as the bonding is usually too small and has to be replaced with a larger cable.

Any electrician that changes the fuse box, as part of the job, now needs to get a new bonding cable from the new consumer unit to the pipe (water/gas etc) entry point which is often found in the cupboard under the sink.

Getting a new cable from the consumer unit position to the water pipe entry position can be a difficult task, to say the least. Floorboards often need lifting, holes need drilling etc to find a route for the cable.

As customers can imagine this work adds a lot of time to the time it takes to complete the fuse box replacement.

What Can Make a Fuse Box / Consumer Unit Change Quicker?

The number of electrical circuits connected to a fuse box has a large impact on how quickly an electrician can change a fuse box. The smaller the number of circuits, the less time it takes to make the connections and the less time it takes to test and verify the circuits upon completion.

The age of the property and the existing electrical installation also plays a large part in the timescale to replace a fuse box.

Newer properties often have electrical installations that are closer to the latest regulations so only minor, quick upgrades are needed to ensure compliance.

Sometimes electricians will want to do a thorough test of the property before beginning work so they can estimate an accurate timescale and an accurate price for the work.

Do I Need an EICR Before a Fuse Box Change?

An option to speed up a fuse box change is to have an Electrical Inspection Condition Report (EICR) done prior to the fuse box being changed. This report is like an MOT for your home electrical systems and will highlight any circuits that do not meet current regulations.

The major advantage of an EICR being completed before a fuse box change is that it gives a very accurate picture of the condition of the electrical circuits. This allows the electrician to make a much better time estimate on how long the fuse box change, (and the required testing) is going to take.

As we saw earlier, once an electrician has changed the fuse box they are now responsible for making all the circuits comply with regulations. This can make the fuse box change take unexpectedly longer if issues are discovered during testing.

In contrast, during an EICR the electrician is not compelled by the regulations to make any improvements (except for code 1 immediate danger issues, which are rare).

After having an EICR, the homeowner can make an informed decision on whether the cost and timescale of getting the fuse box replaced is work they still want to have done BEFORE any fuse box replacement begins.

The EICR is an assessment of the electrical installation within the home. The homeowner can choose to make improvements or not based on its recommendations. In the same way, a garage can tell you your car has failed an MOT, it is the car owner’s responsibility to get it fixed if they choose to do so, not the garage’s responsibility.

Will the Electricity be Off During a Fuse Box Change?

Electricity being switched off for a fuse box replacement
Electricity being switched off for a fuse box replacement

During a fuse box/consumer unit replacement, the electricity to the home will need to be switched off for the duration of the work. Electrical items within the home will not be able to be used for the entire duration of the work, including these commonly forgotten items of equipment.

Needing to have the electricity switched off during a fuse box replacement is what makes this quite a disruptive job for customers.

From my experience some things to consider the day before a fuse box replacement are:

  • Charging all electrical appliances the night before so they have full battery life.
  • Remember the Wifi router will be switched off so the internet will be down.
  • Fridges and freezers are ok for the day as long as the doors are left closed
  • Washing machines should not be half way through a cycle when the power is turned off.

When I attend customers’ homes to replace a fuse box their main concern is usually the freezer defrosting.

Will My Fridge and Freezer Defrost During a Fuse Box Change?

Food can remain fresh in a fridge without power for up to 4 hours in a refrigerator, 24 hours in a half freezer and 48 hours in a full freezer. Source

Keeping the doors closed (especially the freezer door) is the best way to prevent early defrosting. We’ve carried out hundreds of fuse box replacements and the fridges and freezers are always ok to be switched off for the day.

Remember to check the fridge and freezer are plugged in and working as an electrician will unplug them to carry out their tests. It’s always worth double-checking that they remembered to plug them back in and switch the socket-outlet back on!

I hope this has served as a good guide to customers getting the fuse boxes replaced. We also have articles regarding timescales for socket outlet replacements as well as light fitting replacements which you may find helpful.

Having a fuse box change may also be. good opportunity to have some new interlinked hard wired smoke alarms installed.

Dave Nicholas

I have worked as a professional electrician for many years and like to use my experience to help others in any little way I can.

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