Guide to Consumer Units | Considerations for Electrical Safety

A consumer unit, often referred to as a fuse box or distribution board, is a critical component of your home’s electrical system. It distributes electrical power to various circuits around your house and includes protective devices that safeguard your electrical installations. These protective devices can be circuit breakers (CB), residual current devices (RCDs), or residual current circuit breakers with overcurrent protection (RCBOs), which protect against electrical faults and prevent fires or electrical shocks.

Electricity in Your Home

Electricity powers all the appliances and devices in your home. In the UK, the standard system is alternating current (AC) distributed at 230 Volts (V). Your consumer unit manages the flow of this electricity to ensure safe and efficient distribution to different circuits within your home.

Each circuit in your home will have a specific purpose, such as lighting, kitchen appliances, or electric heating. These circuits are protected by individual fuses or circuit breakers in the consumer unit, which will trip and cut off the power if they detect an electrical fault.

Consumer Unit Components

1.  Main Switch: The main switch controls the electrical supply to your entire home. It allows you to turn off the electricity supply quickly in case of an emergency.

2. Circuit Breakers (CB): Circuit breakers protect individual circuits from overloads and short circuits. They will trip and cut the power if the current exceeds safe levels, preventing potential damage or fires.

3.  Residual Current Devices (RCDs): RCDs protect against electrical shocks by detecting imbalances between line and neutral wires. If an imbalance is detected, indicating a leakage current possibly due to a person touching a live part, the RCD will trip and cut off the power. This normally happens within 0.3s- so its vital these are working correctly!

4. Residual Current Circuit Breakers with Overcurrent Protection (RCBOs): RCBOs combine the functions of RCDs and CBs. They provide protection against both electrical faults and leakage currents, ensuring comprehensive safety for individual circuits. This now the preferred installation method used in new consumer units.

5. Surge Protection Devices (SPDs): SPD's are now a requirement in all electrical installations. These devices can help save your electrical installation/appliances from overvoltage's (think lighting strikes). Most modern day electrical equipment contain electronic components - it is these devices that can benefit from SPDs.

Different Measurements and Ratings

• Ampere (A): The unit of electric current. Each circuit breaker is rated in amperes, indicating the maximum current it can handle before tripping.

• Voltage (V): The unit of electric potential. Standard household voltage in the UK is 230V.

• Kilowatt (kW): A measure of power. It represents the rate at which electrical energy is consumed or produced (for more details please read the guide to solar and battery)

How to Get the Most Out of Your Consumer Unit

1. Regular Maintenance: Ensure your consumer unit is checked regularly by a qualified electrician. Regular inspections can identify potential issues before they become serious problems.

2. Upgrade When Necessary: Older consumer units with traditional fuses may not provide the same level of protection as modern units with CBs and RCDs. Upgrading to a modern consumer unit can enhance safety and efficiency.

3. Understand Your Circuits: Know which circuit breakers control which parts of your home. Label each circuit clearly on the consumer unit for easy identification.

4. Balance Your Load: Avoid overloading any single circuit by distributing high-power appliances across multiple circuits. This can prevent circuit breakers from tripping unnecessarily.

5. Consider Smart Upgrades: Modern consumer units can be equipped with smart technology to monitor and manage your electricity usage more effectively. Smart units can provide real-time data on power consumption and alert you to potential issues.

Our Top Tips

• Label Your Circuits: Clearly label each circuit on your consumer unit to quickly identify which breaker controls which area of your home.

• Schedule Regular Checks: Have your consumer unit inspected by a qualified electrician at least every 10 years, or more frequently if advised. Remember, just because you have never had a fault occur does not mean that your electrics are safe.

• Upgrade for Safety: Consider upgrading to a modern consumer unit with RCBOs for enhanced protection against both overcurrent and electrical faults and less inconvenience if it does trip (i.e., only that circuit will trip, leaving all the rest of your house working normally).

• Monitor Load: Keep an eye on the load of each circuit to avoid overloading. Spread high-power appliances across different circuits to balance the load (where possible).

• Stay Informed: Understand the basics of how your consumer unit works and how to reset circuit breakers if they trip. 

Please note that manufacturers' products may differ, and it is always recommended to check the specifics of any system designed for you.