The consumer unit distributes and protects the electrical circuits in a property. An upgrade should be based on the existing installation, the reason for the change and the results of the relevant checks—not selected from a generic online price alone.
When to enquire
Define the scope
What a board replacement covers
A modern board brings RCD protection, correctly rated protective devices, a non-combustible enclosure and usually surge protection. What it does not do is repair the circuits behind it. That distinction is the single most important thing to understand before agreeing the work.
Circuits that were quietly leaking to earth for years — an ageing shower, damp reaching outdoor lighting, a failing appliance — will now trip an RCD that was previously not there. This is why circuits are tested before and after the change, and why any pre-existing fault should be identified and priced as separate remedial work rather than discovered on the day.
On a dual-RCD board a fault on any circuit in a group takes the whole group off, including your lights and your freezer. With RCBOs each circuit has its own device, so a fault only disconnects the affected circuit and fault finding is far simpler.
Since the current regulations and their amendments, surge protective devices are expected in most new installations unless a documented risk assessment decides otherwise. They mount in the board, so a replacement is the natural moment.
Main protective bonding to incoming gas and water services is checked as part of the work. Missing or undersized bonding is one of the most common findings and often has to be corrected before the change is complete.
Replacing a consumer unit is notifiable under Part P. You should receive an Electrical Installation Certificate and a Building Regulations compliance certificate.
Include the postcode, preferred timing and any useful existing information.