This well-cremated consumer unit (home distribution board) was sent by Nick Bundy for our entertainment. You can see the video where he replaces it with a new one here:-
• Fuseboard Fire, House ...
From 2016 all new consumer units in the UK tend to be metal cased ones to reduce the risk of incidents like this. This may have been influenced by a number of recalls related to Wylex circuit breakers with contact burning issues.
Under fault conditions a circuit breaker in the UK can potentially have to break a fault current of several thousand amps, so I've never really been comfortable with the value engineering that has been applied to them. £3 or less seems just too low for something so important to electrical safety.
It's possible that the root of this fault was either a faulty isolator or poor termination. There's a lot more to terminating a cable than just stuffing it into a hole and clamping it with a screw. With rigid cables like the tails shown, it's especially important that the rigidity of the cable doesn't result in a twisting force on the terminal, as it can potentially affect contact positioning.
It's also important to recheck that terminals haven't loosened when cables are moved.
It's interesting to note that both RCDs were in their tripped state, but while they isolated all wiring leading from the fire they couldn't isolate the cause itself.
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