Changing a Consumer Unit - The Complete Guide

Feb 4, 2024


Welcome to Prometheus Electrical, your go-to resource for all your electrical needs. In this article, we will provide you with a comprehensive guide on changing a consumer unit, also known as a fuse box. Whether you are a DIY enthusiast or a professional electrician, our step-by-step instructions, safety precautions, and expert tips will help you upgrade your electrical system efficiently and safely.

Why Change a Consumer Unit?

Before we delve into the process of changing a consumer unit, let's understand why it is necessary. Consumer units play a crucial role in your electrical system, ensuring the distribution of electricity to different circuits in your home or office. Over time, consumer units can become outdated, overloaded, or pose safety hazards. Upgrading to a modern consumer unit not only enhances safety but also allows for better energy management and protection against electrical faults.

Step-by-Step Guide to Changing a Consumer Unit

Step 1: Preparation

Before you start the process, ensure that you have the necessary tools and equipment. This includes a new consumer unit, circuit breakers, cable connections, screwdrivers, pliers, wire strippers, and electrical tester. Always remember to wear appropriate protective gear such as gloves and safety goggles.

Step 2: Turn Off the Main Switch

Prioritize safety by turning off the main switch to disconnect the power supply. This minimizes the risk of electric shock while working on the consumer unit.

Step 3: Take Note of Existing Connections

Before removing the old consumer unit, take note of the existing cable connections. It is essential to ensure that you reconnect the cables correctly to the corresponding terminals in the new consumer unit.

Step 4: Remove the Old Consumer Unit

Carefully remove the cover of the old consumer unit, exposing the circuit breakers and connections. Disconnect the cables and remove the old unit from the wall. Make sure to follow the manufacturer's instructions for detachment to avoid any damage.

Step 5: Install the New Consumer Unit

Position the new consumer unit on the wall, aligning it with the existing holes or marking new ones if required. Secure the unit in place using appropriate fixing methods, as advised by the manufacturer.

Step 6: Reconnect the Cables

Referencing your notes from Step 3, reconnect the cables to their respective terminals in the new consumer unit. Double-check each connection to ensure they are secured tightly and properly insulated.

Step 7: Test the Connections

After reconnecting the cables, it is essential to test the integrity of the connections. Use an electrical tester to verify the continuity and functionality of each circuit.

Step 8: Test the RCD

If your new consumer unit includes a Residual Current Device (RCD), test its functionality by pressing the test button. The RCD should trip, indicating that it is working correctly.

Step 9: Switch on the Main Power

Once you have successfully completed the previous steps, switch on the main power to restore electricity to your home or office. Test each circuit to ensure they are working correctly and address any issues if detected.

Safety Precautions

When changing a consumer unit, it is crucial to prioritize safety to protect yourself and others. Keep the following safety precautions in mind:

  • Always switch off the main power before starting any work.
  • Wear appropriate protective gear, including gloves and safety goggles.
  • Ensure you have a clear understanding of the electrical connections involved.
  • Double-check the stability of the consumer unit after installation.
  • If unsure or uncomfortable, consult a qualified electrician.


Congratulations! By following our comprehensive guide, you have successfully learned how to change a consumer unit. Remember, electrical work can be complex and potentially dangerous, so it is always recommended to consult a professional if you are uncertain or require assistance. At Prometheus Electrical, our team of expert electricians is ready to help you ensure the safety and efficiency of your electrical system. Contact us today to schedule a consultation or learn more about our services!

Disclaimer: The information provided in this article is for educational purposes only. Prometheus Electrical will not be held liable for any damages or injuries that may occur as a result of following these instructions. If in doubt, always consult a qualified electrician.