Why your new fuse box needs verification
Posted on 18th October 2023
Replacing an electrical home consumer unit (once known as your old-fashioned fuse box) is an alteration to your electrical installation.
Alterations and additions qualify as ‘new work’ so the Wiring Regulations apply to their design and installation.
Once the installation is complete verification confirms it meets the requirements of the Regulations. You should receive an electrical installation certificate as confirmation.
What work will you need?
New consumer units and devices
New consumer units and their enclosures should be made from non-combustible material. They should be designed to include:
miniature circuit breakers (MCBs)
residual current operated circuit breakers (RCBOs)
arc fault detection devices (AFDDs)
surge protective devices (SPDs).
These requirements are included in the Regulations to provide better protection and electrical safety than old fashioned fuses.
Existing circuits and the Wiring Regulations
It’s possible to connect your existing wiring to your new consumer unit. However, the Regulations include specific requirements to protect each circuit.
For example, using a residual current device (RCD) for buried or concealed cables without earthed metallic coverings. If you have existing circuits like this in your walls and petitions this will provide extra protection. Circuits passing through or for equipment in bathrooms or showers and for electrical sockets up to 32A also need RCDs.
AFDDs provide protection for single-phase AC circuits supplying socket-outlets up to 32A in certain buildings, possibly also with an RCBO.
Unless you’re happy to confirm that overvoltage protection isn’t needed you’ll also need SPDs.
Other things to think about
We take it for granted that we can plug-in all sorts of appliances and portable devices. Protection for standing earth leakage can help avoid unwanted RCD tripping. This sometimes isn’t possible when just one RCD device protects several circuits. It’s also important to make sure that inspection, testing and maintenance can take place safely.
Please get in touch if you’re planning to change your consumer unit or add new electrical circuits in your home.
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