Two phrases come up again and again when people talk to electricians: consumer unit and EICR. They sound technical, but the ideas behind them are simple. This guide explains both in plain English, so you know what you are being told and why it matters.

What is a consumer unit?

The consumer unit is the box, usually in a hall cupboard, under the stairs or near the front door, where the electricity supply to your home is split into separate circuits. Older versions are often called fuse boxes.

Inside, you will find:

A main switch that turns off power to the whole home.
Circuit breakers (MCBs) for each circuit, such as lights, sockets, cooker and shower. If a circuit is overloaded or has a fault, its breaker trips.
RCDs (residual current devices), which detect earth leakage, the kind of fault that could give someone a shock, and cut the power very quickly.
RCBOs, which combine the breaker and RCD in one device for an individual circuit.

When does a consumer unit need upgrading?

Not every old consumer unit needs replacing, but there are common reasons to upgrade:

Rewireable fuses. If your fuse box uses pieces of fuse wire, it is very old and offers less protection than modern devices.
No RCD protection. Modern wiring regulations require RCD protection for most circuits. Without it, you are missing an important safety layer.
Plastic units in some situations. Current regulations call for consumer units in homes to be housed in non-combustible enclosures, typically metal. Older plastic units are not automatically unsafe, but this is often considered when an upgrade is being done.
No spare capacity. If you are adding an EV charger, heat pump or new circuits, the existing unit may not have room or may not be suitable.
Damage, overheating or nuisance tripping.

An electrician will test the circuits before replacing a consumer unit. Sometimes the tests reveal faults in the wiring that have to be fixed first, because a new unit with modern RCD protection will trip on faults the old one ignored. That is the system working properly.

What is an EICR?

EICR stands for Electrical Installation Condition Report. It is a thorough inspection and test of the fixed electrical installation in a property: the wiring, consumer unit, sockets, switches, light fittings and so on. It is not about your kettle or TV, which are covered by portable appliance testing if needed.

The electrician checks the condition of the installation against current standards and records any issues. Each issue is given a code:

C1 means danger present, needing immediate action.
C2 means potentially dangerous, needing urgent action.
C3 means improvement recommended, but not currently unsafe.
FI means further investigation is needed.

The report will say overall whether the installation is satisfactory or unsatisfactory. A C1, C2 or FI usually makes the report unsatisfactory until the work is done.

Who needs an EICR?

Landlords in Scotland. Private landlords must ensure electrical safety under the Repairing Standard. That includes having an EICR carried out by a competent person at least every five years, along with checks on appliances they provide. If you let property in Edinburgh or the Lothians, you need a current report and should keep a copy for your tenants.

Homeowners. There is no legal requirement for owner-occupiers, but an EICR is a good idea roughly every ten years, when you buy a home, or before a major renovation. It gives you a clear picture of what you have.

Businesses. Commercial premises have their own duties under health and safety law, and regular inspection is the normal way to show the installation is maintained.

What happens on the day?

The electrician will need access to the consumer unit and to every room. Power will be off for periods while circuits are tested, so plan around fridges, freezers, computers and anything that needs to stay on. The time it takes depends on the size and condition of the property.

Afterwards you receive the report, with any observations explained. A good electrician will talk you through it and give a separate quote for any remedial work, so you can decide what to do.

The short version

The consumer unit is your home's electrical control centre and safety system. Upgrade it if it is very old, lacks RCD protection or cannot cope with new loads. An EICR is a health check of the whole installation, required regularly for Scottish landlords and sensible for homeowners.

If you need an EICR or want advice on your consumer unit, send your address and a short note through the contact form and we will come back to arrange a time.

Send a brief

Consumer Units and EICRs in Plain English: A Guide for Edinburgh Homeowners and Landlords