Do You Actually Need a New Consumer Unit?
Often the honest answer is no, which is not what you will hear from someone who sells them.
A consumer unit replacement is one of the most commonly oversold jobs in domestic electrics. Sometimes it is genuinely necessary. Often it is a C3 being presented as an emergency.
When It Genuinely Is Needed
A rewirable fuse board with no RCD protection at all, damage or overheating on the unit itself, or a board so full that there is nowhere to add a required circuit. Also when the earthing arrangement is inadequate, though that is a separate fix that often gets bundled in.
When It Is Being Oversold
“It is plastic and plastic is banned” — not true for existing installations, only for new ones in certain locations. “It has no RCD so it is illegal” — an existing installation is not illegal for being built to an older standard. Both are C3 territory: worth improving, not urgent.
What a Replacement Involves
A full day, power off for most of it, and every circuit tested and certified afterwards. If somebody quotes two hours, they are not testing properly, and the certificate that follows is not worth much.
The Question to Ask
“Which code would this attract on an EICR, and why?” A contractor who can answer C1, C2 or C3 and explain the reasoning is giving you a technical opinion. One who cannot is giving you a sales pitch.
