01/11/2020
Lately I have been doing a lot of fuse board upgrades. They are often complicated and require a lot of problem solving so here is some information about what is involved.
I usually split a fuse board upgrade into 3 stages:
Inspection and testing:
This stage is similar to an Electrical Installation Condition Report (EICR): https://electrician-sheffield.co.uk/condition-reports/
The first day, or sometimes longer, is spent going round the house testing and checking behind accessories (sockets, light switches, etc) to ensure there are no faults. It is important that this is done before the board is changed. Modern fuse boards/consumer units contain devices called RCDs, which are a lot more sensitive than fuses or circuit breakers, and will trip in the event of an earth fault. This type of fault would go unnoticed by most older boards, as fuses and circuit breakers are only designed to trip in the event of an overload or short circuit fault.
If the board was changed first without testing, and there was an earth fault on the wiring, the RCD just wouldn't switch on and the property will potentially be left without any power and/or lights until the faults are identified and cleared.
Remedial work:
Any faults and/or non-compliant work is corrected at this stage.
It is rare to have a fuse board change where there little or no remedial work is required. Especially in older properties or where there have been multiple modifications done to the wiring by different people.
Board change:
Once the above stages have been carried out, the board change is often the most straightforward part of the job; as I can be sure there will be no nuisance tripping when the power back is switched back on. This stage, however, can be time consuming if the position of the board needs to change, as shown in the examples below.
