Consumer Unit Upgrade Guide for Homes in Blackpool and the Fylde

The consumer unit is the box, usually near the front door, under the stairs or in the garage, that splits the electricity coming into your home between the different circuits. Many people still call it the fuse box. If your home in Blackpool, Fleetwood, Kirkham or Preston has an older one, this guide explains why replacing it is often worthwhile, what the job involves and what you should be given when it is finished. It applies to homes in England.

What a consumer unit does

Every circuit in your house, such as the lights upstairs, the ring of sockets in the kitchen or the cooker, runs back to the consumer unit. Each circuit has a protective device that switches it off if something goes wrong. Older units use fuses, either rewirable or cartridge types. Modern units use circuit breakers and RCDs.

An RCD, or residual current device, is a safety device that monitors the current flowing through a circuit. If it detects that some of that current is leaking, for example through a person who has touched a live part, it switches the circuit off very quickly. That can be the difference between a nasty shock and a serious injury. RCDs are one of the most important protections in a modern home.

Signs that yours may need replacing

You cannot judge a consumer unit by its looks alone, but these are common reasons to have it looked at:

• It has rewirable fuses, or a mix of old fuses and breakers.
• It has no RCD protection at all. Many older homes do not.
• It has a wooden back-board or a plastic casing that has discoloured or looks scorched.
• Circuits trip or fuses blow often, or there are signs of heat, a burning smell or buzzing from the box.
• It is crowded, with no space for new circuits.
• You are adding something that needs its own circuit, such as an electric shower, an EV charger or a heat pump.
• An inspection report has recommended it. See our EICR guide for how to read the codes.

A consumer unit is not automatically unsafe because it is old, and replacing it is not a legal requirement for an owner-occupier. The decision is a matter of safety and practicality, and a registered electrician can tell you which applies to your home after looking at it.

Why modern units are safer

Modern consumer units are designed with a range of protections that older ones lack:

• RCD protection. The wiring regulations, BS 7671, call for RCD protection on most circuits in a home. Modern units are normally arranged so that a fault on one circuit does not take down every circuit in the house.
• Non-combustible enclosure. BS 7671 now calls for consumer units in homes to be housed in a non-combustible enclosure, typically made of metal. This limits the spread of fire if there is a fault inside the unit.
• Surge protection. The regulations call for surge protection to be considered in a wider range of situations, and your electrician will advise on whether it is appropriate.
• Clear labelling. Each circuit is labelled, which makes it much easier to isolate the right part of the house safely.

The regulations are updated from time to time, so the exact requirements depend on the version of BS 7671 current when the work is done. Your electrician should work to the latest edition and tell you what has been fitted.

Splitting the protection across the house

One thing that surprises many people is that a consumer unit with a single RCD covering everything can mean that one fault leaves the whole house in the dark. Most modern units are arranged with more than one RCD, or with circuit breakers that have RCD protection built in, so a fault on one circuit only takes out that circuit. This is more convenient, and it matters for safety too, for example when you do not want the freezer or the lights on the stairs to be lost because of a fault in a garden socket.

If your electrician suggests a particular arrangement, ask them why they recommend it and what will happen when a fault occurs.

What the work involves

A consumer unit replacement is normally planned for a few hours to a day, depending on how many circuits there are and what condition the wiring is in. The typical stages are:

1. Assessment. The electrician looks at the existing unit, the earthing and bonding arrangements and the type of supply to the property, and may carry out some tests before work starts. This is important because the installation needs to be safe to connect to a new unit.
2. Agreeing the scope. You should be told which circuits will be reconnected, what will be tested and whether any other work, such as correcting earth bonding or fixing damaged cables, is needed first. Get this in writing.
3. Isolation. The supply to the property is switched off at the meter or the main switch. Tell your electrician about anyone at home who depends on medical equipment, and plan around freezers, alarms and computers.
4. Replacing the unit. The old unit is removed, the new one is fitted and each circuit is reconnected and labelled.
5. Testing and certification. Every circuit is tested before the supply is restored and the results are recorded on the certificate.
6. Handover. The electrician explains how to use the unit, how to test the RCDs and which circuit is which.

The power will be off for part of the day, so ask about timing when you book.

Paperwork you should receive

In England, replacing a consumer unit is notifiable work under Part P of the Building Regulations. That means it must either be carried out by an electrician registered with a competent person scheme, who can notify the work themselves, or be notified to your local authority building control before work starts. You can read more in our guide to Part P and electrical certificates.

When the work is complete you should receive:

• an Electrical Installation Certificate, or a Minor Works certificate where appropriate, with the test results;
• confirmation that the work has been notified to building control, normally as a Building Regulations compliance certificate that follows later from the electrician's scheme or the council.

Keep these documents safe. You will want them if you sell the property, apply for insurance or have to show a landlord's duties have been met.

Do it yourself?

It is tempting to look for a cheaper way to do this, but changing a consumer unit is not a DIY job. The work involves connecting to the live supply, and mistakes can cause fire, electric shock or damage that may not show up for years. NICEIC advises that you should never attempt DIY electrics in any area of your home. A non-registered installer may also leave you without the notification and certificates you need, which can cause problems with insurance and when you sell. Our guide to choosing a registered electrician explains what to check.

Other things worth checking at the same time

A consumer unit change is a good opportunity to review the rest of the installation:

• Check the earthing and bonding of gas and water pipes, which should be confirmed during the work.
• Look for circuits that are overloaded or that have too many extension leads attached.
• Ask for smoke or heat alarms to be reviewed, see our smoke and heat alarm guide.
• If an EV charger or heat pump is planned, ask for the unit to be chosen with spare capacity and a suitable way to protect the new circuit.

If you would like us to take a look at your fuse box, see our domestic electrical service, call 01253 364101 or send an enquiry through the website.