my old fusebox...
What I didn't realise about my old fusebox was just how dangerous it was. I live in a two storey house in Hove and I should have devices called RCDs (Residual Current Devices) fitted to my fuseboard.
The RCD is a clever device because it works differently to a normal fuse or circuit breaker. My old fuses were rated from 5Amps to 30Amps, which means the current during a fault (short circuit) would have to exceed that amount before the fusewire melts. That's a lot of current flowing around especially when it is accepted that a fatal heart attack will occur in an average, healthy human at only 0.05 Amps (50 milliApms)! There's an interesting although somewhat macabre guide to the Physiological Effect of Electric Shock at http://pchem.scs.uiuc.edu/pchemlab/electric.htm
The clever thing about an RCD is that it measures all the current going into a circuit (via the 'live' wire) and compares it with all the current coming out (via the 'neutral' wire). If there is a difference of only 30 milliAmps (0.03 Amps) then the RCD will recognise somebody somewhere is getting a shock and break the circuit instantaneously. Now, although you'd probably still feel a shock of 30milliAmps, it won't kill you.
So basically, once you have RCDs fitted then you can never receive a fatal shock from those protected circuit.
As old fuseboxes with rewireable fuses do not have RCD capability, other methods of shock protection must be considered. One option is to replace all sockets with special RCD sockets, however, these devices are expensive and not particularly attractive as each outlet has a distinctive green test button. So practically it's just as easy to install a new split-load consumer unit.
Another problem I discovered was with the upgrading of my local sub-station. Previously, the old sub-station could deliver a hefty wack to my fusebox if I had a short circuit but my fusebox should in theory be able to take it. Now the new sub-station can deliver much more energy to my fusebox during a short circuit. More energy in fact than my fusbox is rated at.
So, basically, thanks to (name removed by fuseboxheroes) replacing the local sub-station I ran the risk of my old rewirable fuseholder spitting out molten fusewire about the dusty old hallway cupboard. Not a comforting thought.
In any event, it was my responsibility to look after the electrics on my side of the meter so I had to bite bullet and call in the electrician.
Ivan MacTaggart - Hove